Native support for PnP

src/compiler/moduleNameResolver.ts

@@ -110,6 +110,10 @@ import {
  versionMajorMinor,
  VersionRange,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+ getPnpTypeRoots,
+} from "./pnp";
 
 /** @internal */
 export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void {
@@ -471,7 +475,7 @@ export function getEffectiveTypeRoots(options: CompilerOptions, host: GetEffecti
  * Returns the path to every node_modules/@types directory from some ancestor directory.
  * Returns undefined if there are none.
  */
-function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+function getNodeModulesTypeRoots(currentDirectory: string) {
  let typeRoots: string[] | undefined;
  forEachAncestorDirectory(normalizePath(currentDirectory), directory => {
  const atTypes = combinePaths(directory, nodeModulesAtTypes);
@@ -486,6 +490,18 @@ function arePathsEqual(path1: string, path2: string, host: ModuleResolutionHost)
  return comparePaths(path1, path2, !useCaseSensitiveFileNames) === Comparison.EqualTo;
 }
 
+function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+ const nmTypes = getNodeModulesTypeRoots(currentDirectory);
+ const pnpTypes = getPnpTypeRoots(currentDirectory);
+
+ if (nmTypes?.length) {
+ return [...nmTypes, ...pnpTypes];
+ }
+ else if (pnpTypes.length) {
+ return pnpTypes;
+ }
+}
+
 function getOriginalAndResolvedFileName(fileName: string, host: ModuleResolutionHost, traceEnabled: boolean) {
  const resolvedFileName = realPath(fileName, host, traceEnabled);
  const pathsAreEqual = arePathsEqual(fileName, resolvedFileName, host);
@@ -770,6 +786,18 @@ export function resolvePackageNameToPackageJson(
 ): PackageJsonInfo | undefined {
  const moduleResolutionState = getTemporaryModuleResolutionState(cache?.getPackageJsonInfoCache(), host, options);
 
+ const pnpapi = getPnpApi(containingDirectory);
+ if (pnpapi) {
+ try {
+ const resolution = pnpapi.resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ const candidate = normalizeSlashes(resolution).replace(/\/$/, "");
+ return getPackageJsonInfo(candidate, /*onlyRecordFailures*/ false, moduleResolutionState);
+ }
+ catch {
+ return;
+ }
+ }
+
  return forEachAncestorDirectory(containingDirectory, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const nodeModulesFolder = combinePaths(ancestorDirectory, "node_modules");
@@ -2938,7 +2966,16 @@ function loadModuleFromNearestNodeModulesDirectoryWorker(extensions: Extensions,
  }
 
  function lookup(extensions: Extensions) {
- return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
+ const issuer = normalizeSlashes(directory);
+ if (getPnpApi(issuer)) {
+ const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, issuer, redirectedReference, state);
+ if (resolutionFromCache) {
+ return resolutionFromCache;
+ }
+ return toSearchResult(loadModuleFromImmediateNodeModulesDirectoryPnP(extensions, moduleName, issuer, state, typesScopeOnly, cache, redirectedReference));
+ }
+
+ return forEachAncestorDirectory(issuer, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, ancestorDirectory, redirectedReference, state);
  if (resolutionFromCache) {
@@ -2977,11 +3014,34 @@ function loadModuleFromImmediateNodeModulesDirectory(extensions: Extensions, mod
  }
 }
 
+function loadModuleFromImmediateNodeModulesDirectoryPnP(extensions: Extensions, moduleName: string, directory: string, state: ModuleResolutionState, typesScopeOnly: boolean, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const issuer = normalizeSlashes(directory);
+
+ if (!typesScopeOnly) {
+ const packageResult = tryLoadModuleUsingPnpResolution(extensions, moduleName, issuer, state, cache, redirectedReference);
+ if (packageResult) {
+ return packageResult;
+ }
+ }
+
+ if (extensions & Extensions.Declaration) {
+ return tryLoadModuleUsingPnpResolution(Extensions.Declaration, `@types/${mangleScopedPackageNameWithTrace(moduleName, state)}`, issuer, state, cache, redirectedReference);
+ }
+}
+
 function loadModuleFromSpecificNodeModulesDirectory(extensions: Extensions, moduleName: string, nodeModulesDirectory: string, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
  const candidate = normalizePath(combinePaths(nodeModulesDirectory, moduleName));
  const { packageName, rest } = parsePackageName(moduleName);
  const packageDirectory = combinePaths(nodeModulesDirectory, packageName);
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, nodeModulesDirectoryExists, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
 
+function loadModuleFromPnpResolution(extensions: Extensions, packageDirectory: string, rest: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const candidate = normalizePath(combinePaths(packageDirectory, rest));
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, /*nodeModulesDirectoryExists*/ true, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
+
+function loadModuleFromSpecificNodeModulesDirectoryImpl(extensions: Extensions, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined, candidate: string, rest: string, packageDirectory: string): Resolved | undefined {
  let rootPackageInfo: PackageJsonInfo | undefined;
  // First look for a nested package.json, as in `node_modules/foo/bar/package.json`.
  let packageInfo = getPackageJsonInfo(candidate, !nodeModulesDirectoryExists, state);
@@ -3306,3 +3366,22 @@ function useCaseSensitiveFileNames(state: ModuleResolutionState) {
  typeof state.host.useCaseSensitiveFileNames === "boolean" ? state.host.useCaseSensitiveFileNames :
  state.host.useCaseSensitiveFileNames();
 }
+
+function loadPnpPackageResolution(packageName: string, containingDirectory: string) {
+ try {
+ const resolution = getPnpApi(containingDirectory).resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ return normalizeSlashes(resolution).replace(/\/$/, "");
+ }
+ catch {
+ // Nothing to do
+ }
+}
+
+function tryLoadModuleUsingPnpResolution(extensions: Extensions, moduleName: string, containingDirectory: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined) {
+ const { packageName, rest } = parsePackageName(moduleName);
+
+ const packageResolution = loadPnpPackageResolution(packageName, containingDirectory);
+ return packageResolution
+ ? loadModuleFromPnpResolution(extensions, packageResolution, rest, state, cache, redirectedReference)
+ : undefined;
+}

src/compiler/moduleSpecifiers.ts

@@ -84,6 +84,7 @@ import {
  NodeFlags,
  NodeModulePathParts,
  normalizePath,
+ PackagePathParts,
  Path,
  pathContainsNodeModules,
  pathIsBareSpecifier,
@@ -110,6 +111,9 @@ import {
  TypeChecker,
  UserPreferences,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+} from "./pnp";
 
 // Used by importFixes, getEditsForFileRename, and declaration emit to synthesize import module specifiers.
 
@@ -641,7 +645,17 @@ function getAllModulePathsWorker(importingFileName: Path, importedFileName: stri
  host,
  /*preferSymlinks*/ true,
  (path, isRedirect) => {
- const isInNodeModules = pathContainsNodeModules(path);
+ let isInNodeModules = pathContainsNodeModules(path);
+
+ const pnpapi = getPnpApi(path);
+ if (!isInNodeModules && pnpapi) {
+ const fromLocator = pnpapi.findPackageLocator(importingFileName);
+ const toLocator = pnpapi.findPackageLocator(path);
+ if (fromLocator && toLocator && fromLocator !== toLocator) {
+ isInNodeModules = true;
+ }
+ }
+
  allFileNames.set(path, { path: getCanonicalFileName(path), isRedirect, isInNodeModules });
  importedFileFromNodeModules = importedFileFromNodeModules || isInNodeModules;
  // don't return value, so we collect everything
@@ -907,7 +921,51 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  if (!host.fileExists || !host.readFile) {
  return undefined;
  }
- const parts: NodeModulePathParts = getNodeModulePathParts(path)!;
+ let parts: NodeModulePathParts | PackagePathParts | undefined = getNodeModulePathParts(path);
+
+ let pnpPackageName: string | undefined;
+
+ const pnpApi = getPnpApi(path);
+ if (pnpApi) {
+ const fromLocator = pnpApi.findPackageLocator(importingSourceFile.fileName);
+ const toLocator = pnpApi.findPackageLocator(path);
+
+ // Don't use the package name when the imported file is inside
+ // the source directory (prefer a relative path instead)
+ if (fromLocator === toLocator) {
+ return undefined;
+ }
+
+ if (fromLocator && toLocator) {
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ if (toLocator.reference === fromInfo.packageDependencies.get(toLocator.name)) {
+ pnpPackageName = toLocator.name;
+ }
+ else {
+ // Aliased dependencies
+ for (const [name, reference] of fromInfo.packageDependencies) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ pnpPackageName = name;
+ break;
+ }
+ }
+ }
+ }
+
+ if (!parts) {
+ const toInfo = pnpApi.getPackageInformation(toLocator);
+ parts = {
+ topLevelNodeModulesIndex: undefined,
+ topLevelPackageNameIndex: undefined,
+ // The last character from packageLocation is the trailing "/", we want to point to it
+ packageRootIndex: toInfo.packageLocation.length - 1,
+ fileNameIndex: path.lastIndexOf(`/`),
+ };
+ }
+ }
+ }
+
  if (!parts) {
  return undefined;
  }
@@ -952,19 +1010,26 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  return undefined;
  }
 
- const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
- // Get a path that's relative to node_modules or the importing file's path
- // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
- const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
- if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
- return undefined;
+ // If PnP is enabled the node_modules entries we'll get will always be relevant even if they
+ // are located in a weird path apparently outside of the source directory
+ if (typeof process.versions.pnp === "undefined") {
+ const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
+ // Get a path that's relative to node_modules or the importing file's path
+ // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
+ const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
+ if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
+ return undefined;
+ }
  }
 
  // If the module was found in @types, get the actual Node package name
- const nodeModulesDirectoryName = moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = typeof pnpPackageName !== "undefined"
+ ? pnpPackageName + moduleSpecifier.substring(parts.packageRootIndex)
+ : moduleSpecifier.substring(parts.topLevelPackageNameIndex! + 1);
+
+ const packageNameFromPath = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
  // For classic resolution, only allow importing from node_modules/@types, not other node_modules
- return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageName === nodeModulesDirectoryName ? undefined : packageName;
+ return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageNameFromPath === nodeModulesDirectoryName ? undefined : packageNameFromPath;
 
  function tryDirectoryWithPackageJson(packageRootIndex: number): { moduleFileToTry: string; packageRootPath?: string; blockedByExports?: true; verbatimFromExports?: true; } {
  const packageRootPath = path.substring(0, packageRootIndex);
@@ -979,8 +1044,8 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  // The package name that we found in node_modules could be different from the package
  // name in the package.json content via url/filepath dependency specifiers. We need to
  // use the actual directory name, so don't look at `packageJsonContent.name` here.
- const nodeModulesDirectoryName = packageRootPath.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = packageRootPath.substring(parts!.topLevelPackageNameIndex! + 1);
+ const packageName = getPackageNameFromTypesPackageName(pnpPackageName ? pnpPackageName : nodeModulesDirectoryName);
  const conditions = getConditions(options, importMode === ModuleKind.ESNext);
  const fromExports = packageJsonContent.exports
  ? tryGetModuleNameFromExports(options, path, packageRootPath, packageName, packageJsonContent.exports, conditions)
@@ -1046,7 +1111,7 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  }
  else {
  // No package.json exists; an index.js will still resolve as the package name
- const fileName = getCanonicalFileName(moduleFileToTry.substring(parts.packageRootIndex + 1));
+ const fileName = getCanonicalFileName(moduleFileToTry.substring(parts!.packageRootIndex + 1));
  if (fileName === "index.d.ts" || fileName === "index.js" || fileName === "index.ts" || fileName === "index.tsx") {
  return { moduleFileToTry, packageRootPath };
  }

src/compiler/pnp.ts

@@ -0,0 +1,80 @@
+import {
+ getDirectoryPath,
+ resolvePath,
+} from "./path";
+
+export function getPnpApi(path: string) {
+ if (typeof process.versions.pnp === "undefined") {
+ return;
+ }
+
+ const { findPnpApi } = require("module");
+ if (findPnpApi) {
+ return findPnpApi(`${path}/`);
+ }
+}
+
+export function getPnpApiPath(path: string): string | undefined {
+ // eslint-disable-next-line no-null/no-null
+ return getPnpApi(path)?.resolveRequest("pnpapi", /*issuer*/ null);
+}
+
+export function getPnpTypeRoots(currentDirectory: string) {
+ const pnpApi = getPnpApi(currentDirectory);
+ if (!pnpApi) {
+ return [];
+ }
+
+ // Some TS consumers pass relative paths that aren't normalized
+ currentDirectory = resolvePath(currentDirectory);
+
+ const currentPackage = pnpApi.findPackageLocator(`${currentDirectory}/`);
+ if (!currentPackage) {
+ return [];
+ }
+
+ const { packageDependencies } = pnpApi.getPackageInformation(currentPackage);
+
+ const typeRoots: string[] = [];
+ for (const [name, referencish] of Array.from<any>(packageDependencies.entries())) {
+ // eslint-disable-next-line no-null/no-null
+ if (name.startsWith(`@types/`) && referencish !== null) {
+ const dependencyLocator = pnpApi.getLocator(name, referencish);
+ const { packageLocation } = pnpApi.getPackageInformation(dependencyLocator);
+
+ typeRoots.push(getDirectoryPath(packageLocation));
+ }
+ }
+
+ return typeRoots;
+}
+
+export function isImportablePathPnp(fromPath: string, toPath: string): boolean {
+ const pnpApi = getPnpApi(fromPath);
+
+ const fromLocator = pnpApi.findPackageLocator(fromPath);
+ const toLocator = pnpApi.findPackageLocator(toPath);
+
+ // eslint-disable-next-line no-null/no-null
+ if (toLocator === null) {
+ return false;
+ }
+
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ const toReference = fromInfo.packageDependencies.get(toLocator.name);
+
+ if (toReference) {
+ return toReference === toLocator.reference;
+ }
+
+ // Aliased dependencies
+ for (const reference of fromInfo.packageDependencies.values()) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+}

src/compiler/sys.ts

@@ -1728,6 +1728,10 @@ export let sys: System = (() => {
  }
 
  function isFileSystemCaseSensitive(): boolean {
+ // The PnP runtime is always case-sensitive
+ if (typeof process.versions.pnp !== `undefined`) {
+ return true;
+ }
  // win32\win64 are case insensitive platforms
  if (platform === "win32" || platform === "win64") {
  return false;

src/compiler/utilities.ts

@@ -10230,6 +10230,15 @@ export interface NodeModulePathParts {
  readonly packageRootIndex: number;
  readonly fileNameIndex: number;
 }
+
+/** @internal */
+export interface PackagePathParts {
+ readonly topLevelNodeModulesIndex: undefined;
+ readonly topLevelPackageNameIndex: undefined;
+ readonly packageRootIndex: number;
+ readonly fileNameIndex: number;
+}
+
 /** @internal */
 export function getNodeModulePathParts(fullPath: string): NodeModulePathParts | undefined {
  // If fullPath can't be valid module file within node_modules, returns undefined.

src/compiler/moduleNameResolver.ts

@@ -110,6 +110,10 @@ import {
  versionMajorMinor,
  VersionRange,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+ getPnpTypeRoots,
+} from "./pnp";
 
 /** @internal */
 export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void {
@@ -471,7 +475,7 @@ export function getEffectiveTypeRoots(options: CompilerOptions, host: GetEffecti
  * Returns the path to every node_modules/@types directory from some ancestor directory.
  * Returns undefined if there are none.
  */
-function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+function getNodeModulesTypeRoots(currentDirectory: string) {
  let typeRoots: string[] | undefined;
  forEachAncestorDirectory(normalizePath(currentDirectory), directory => {
  const atTypes = combinePaths(directory, nodeModulesAtTypes);
@@ -486,6 +490,18 @@ function arePathsEqual(path1: string, path2: string, host: ModuleResolutionHost)
  return comparePaths(path1, path2, !useCaseSensitiveFileNames) === Comparison.EqualTo;
 }
 
+function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+ const nmTypes = getNodeModulesTypeRoots(currentDirectory);
+ const pnpTypes = getPnpTypeRoots(currentDirectory);
+
+ if (nmTypes?.length) {
+ return [...nmTypes, ...pnpTypes];
+ }
+ else if (pnpTypes.length) {
+ return pnpTypes;
+ }
+}
+
 function getOriginalAndResolvedFileName(fileName: string, host: ModuleResolutionHost, traceEnabled: boolean) {
  const resolvedFileName = realPath(fileName, host, traceEnabled);
  const pathsAreEqual = arePathsEqual(fileName, resolvedFileName, host);
@@ -770,6 +786,18 @@ export function resolvePackageNameToPackageJson(
 ): PackageJsonInfo | undefined {
  const moduleResolutionState = getTemporaryModuleResolutionState(cache?.getPackageJsonInfoCache(), host, options);
 
+ const pnpapi = getPnpApi(containingDirectory);
+ if (pnpapi) {
+ try {
+ const resolution = pnpapi.resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ const candidate = normalizeSlashes(resolution).replace(/\/$/, "");
+ return getPackageJsonInfo(candidate, /*onlyRecordFailures*/ false, moduleResolutionState);
+ }
+ catch {
+ return;
+ }
+ }
+
  return forEachAncestorDirectory(containingDirectory, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const nodeModulesFolder = combinePaths(ancestorDirectory, "node_modules");
@@ -2938,7 +2966,16 @@ function loadModuleFromNearestNodeModulesDirectoryWorker(extensions: Extensions,
  }
 
  function lookup(extensions: Extensions) {
- return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
+ const issuer = normalizeSlashes(directory);
+ if (getPnpApi(issuer)) {
+ const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, issuer, redirectedReference, state);
+ if (resolutionFromCache) {
+ return resolutionFromCache;
+ }
+ return toSearchResult(loadModuleFromImmediateNodeModulesDirectoryPnP(extensions, moduleName, issuer, state, typesScopeOnly, cache, redirectedReference));
+ }
+
+ return forEachAncestorDirectory(issuer, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, ancestorDirectory, redirectedReference, state);
  if (resolutionFromCache) {
@@ -2977,11 +3014,34 @@ function loadModuleFromImmediateNodeModulesDirectory(extensions: Extensions, mod
  }
 }
 
+function loadModuleFromImmediateNodeModulesDirectoryPnP(extensions: Extensions, moduleName: string, directory: string, state: ModuleResolutionState, typesScopeOnly: boolean, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const issuer = normalizeSlashes(directory);
+
+ if (!typesScopeOnly) {
+ const packageResult = tryLoadModuleUsingPnpResolution(extensions, moduleName, issuer, state, cache, redirectedReference);
+ if (packageResult) {
+ return packageResult;
+ }
+ }
+
+ if (extensions & Extensions.Declaration) {
+ return tryLoadModuleUsingPnpResolution(Extensions.Declaration, `@types/${mangleScopedPackageNameWithTrace(moduleName, state)}`, issuer, state, cache, redirectedReference);
+ }
+}
+
 function loadModuleFromSpecificNodeModulesDirectory(extensions: Extensions, moduleName: string, nodeModulesDirectory: string, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
  const candidate = normalizePath(combinePaths(nodeModulesDirectory, moduleName));
  const { packageName, rest } = parsePackageName(moduleName);
  const packageDirectory = combinePaths(nodeModulesDirectory, packageName);
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, nodeModulesDirectoryExists, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
 
+function loadModuleFromPnpResolution(extensions: Extensions, packageDirectory: string, rest: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const candidate = normalizePath(combinePaths(packageDirectory, rest));
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, /*nodeModulesDirectoryExists*/ true, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
+
+function loadModuleFromSpecificNodeModulesDirectoryImpl(extensions: Extensions, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined, candidate: string, rest: string, packageDirectory: string): Resolved | undefined {
  let rootPackageInfo: PackageJsonInfo | undefined;
  // First look for a nested package.json, as in `node_modules/foo/bar/package.json`.
  let packageInfo = getPackageJsonInfo(candidate, !nodeModulesDirectoryExists, state);
@@ -3306,3 +3366,22 @@ function useCaseSensitiveFileNames(state: ModuleResolutionState) {
  typeof state.host.useCaseSensitiveFileNames === "boolean" ? state.host.useCaseSensitiveFileNames :
  state.host.useCaseSensitiveFileNames();
 }
+
+function loadPnpPackageResolution(packageName: string, containingDirectory: string) {
+ try {
+ const resolution = getPnpApi(containingDirectory).resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ return normalizeSlashes(resolution).replace(/\/$/, "");
+ }
+ catch {
+ // Nothing to do
+ }
+}
+
+function tryLoadModuleUsingPnpResolution(extensions: Extensions, moduleName: string, containingDirectory: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined) {
+ const { packageName, rest } = parsePackageName(moduleName);
+
+ const packageResolution = loadPnpPackageResolution(packageName, containingDirectory);
+ return packageResolution
+ ? loadModuleFromPnpResolution(extensions, packageResolution, rest, state, cache, redirectedReference)
+ : undefined;
+}

src/compiler/moduleSpecifiers.ts

@@ -84,6 +84,7 @@ import {
  NodeFlags,
  NodeModulePathParts,
  normalizePath,
+ PackagePathParts,
  Path,
  pathContainsNodeModules,
  pathIsBareSpecifier,
@@ -110,6 +111,9 @@ import {
  TypeChecker,
  UserPreferences,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+} from "./pnp";
 
 // Used by importFixes, getEditsForFileRename, and declaration emit to synthesize import module specifiers.
 
@@ -641,7 +645,17 @@ function getAllModulePathsWorker(importingFileName: Path, importedFileName: stri
  host,
  /*preferSymlinks*/ true,
  (path, isRedirect) => {
- const isInNodeModules = pathContainsNodeModules(path);
+ let isInNodeModules = pathContainsNodeModules(path);
+
+ const pnpapi = getPnpApi(path);
+ if (!isInNodeModules && pnpapi) {
+ const fromLocator = pnpapi.findPackageLocator(importingFileName);
+ const toLocator = pnpapi.findPackageLocator(path);
+ if (fromLocator && toLocator && fromLocator !== toLocator) {
+ isInNodeModules = true;
+ }
+ }
+
  allFileNames.set(path, { path: getCanonicalFileName(path), isRedirect, isInNodeModules });
  importedFileFromNodeModules = importedFileFromNodeModules || isInNodeModules;
  // don't return value, so we collect everything
@@ -907,7 +921,51 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  if (!host.fileExists || !host.readFile) {
  return undefined;
  }
- const parts: NodeModulePathParts = getNodeModulePathParts(path)!;
+ let parts: NodeModulePathParts | PackagePathParts | undefined = getNodeModulePathParts(path);
+
+ let pnpPackageName: string | undefined;
+
+ const pnpApi = getPnpApi(path);
+ if (pnpApi) {
+ const fromLocator = pnpApi.findPackageLocator(importingSourceFile.fileName);
+ const toLocator = pnpApi.findPackageLocator(path);
+
+ // Don't use the package name when the imported file is inside
+ // the source directory (prefer a relative path instead)
+ if (fromLocator === toLocator) {
+ return undefined;
+ }
+
+ if (fromLocator && toLocator) {
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ if (toLocator.reference === fromInfo.packageDependencies.get(toLocator.name)) {
+ pnpPackageName = toLocator.name;
+ }
+ else {
+ // Aliased dependencies
+ for (const [name, reference] of fromInfo.packageDependencies) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ pnpPackageName = name;
+ break;
+ }
+ }
+ }
+ }
+
+ if (!parts) {
+ const toInfo = pnpApi.getPackageInformation(toLocator);
+ parts = {
+ topLevelNodeModulesIndex: undefined,
+ topLevelPackageNameIndex: undefined,
+ // The last character from packageLocation is the trailing "/", we want to point to it
+ packageRootIndex: toInfo.packageLocation.length - 1,
+ fileNameIndex: path.lastIndexOf(`/`),
+ };
+ }
+ }
+ }
+
  if (!parts) {
  return undefined;
  }
@@ -952,19 +1010,26 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  return undefined;
  }
 
- const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
- // Get a path that's relative to node_modules or the importing file's path
- // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
- const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
- if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
- return undefined;
+ // If PnP is enabled the node_modules entries we'll get will always be relevant even if they
+ // are located in a weird path apparently outside of the source directory
+ if (typeof process.versions.pnp === "undefined") {
+ const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
+ // Get a path that's relative to node_modules or the importing file's path
+ // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
+ const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
+ if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
+ return undefined;
+ }
  }
 
  // If the module was found in @types, get the actual Node package name
- const nodeModulesDirectoryName = moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = typeof pnpPackageName !== "undefined"
+ ? pnpPackageName + moduleSpecifier.substring(parts.packageRootIndex)
+ : moduleSpecifier.substring(parts.topLevelPackageNameIndex! + 1);
+
+ const packageNameFromPath = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
  // For classic resolution, only allow importing from node_modules/@types, not other node_modules
- return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageName === nodeModulesDirectoryName ? undefined : packageName;
+ return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageNameFromPath === nodeModulesDirectoryName ? undefined : packageNameFromPath;
 
  function tryDirectoryWithPackageJson(packageRootIndex: number): { moduleFileToTry: string; packageRootPath?: string; blockedByExports?: true; verbatimFromExports?: true; } {
  const packageRootPath = path.substring(0, packageRootIndex);
@@ -979,8 +1044,8 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  // The package name that we found in node_modules could be different from the package
  // name in the package.json content via url/filepath dependency specifiers. We need to
  // use the actual directory name, so don't look at `packageJsonContent.name` here.
- const nodeModulesDirectoryName = packageRootPath.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = packageRootPath.substring(parts!.topLevelPackageNameIndex! + 1);
+ const packageName = getPackageNameFromTypesPackageName(pnpPackageName ? pnpPackageName : nodeModulesDirectoryName);
  const conditions = getConditions(options, importMode === ModuleKind.ESNext);
  const fromExports = packageJsonContent.exports
  ? tryGetModuleNameFromExports(options, path, packageRootPath, packageName, packageJsonContent.exports, conditions)
@@ -1046,7 +1111,7 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  }
  else {
  // No package.json exists; an index.js will still resolve as the package name
- const fileName = getCanonicalFileName(moduleFileToTry.substring(parts.packageRootIndex + 1));
+ const fileName = getCanonicalFileName(moduleFileToTry.substring(parts!.packageRootIndex + 1));
  if (fileName === "index.d.ts" || fileName === "index.js" || fileName === "index.ts" || fileName === "index.tsx") {
  return { moduleFileToTry, packageRootPath };
  }

src/compiler/pnp.ts

@@ -0,0 +1,80 @@
+import {
+ getDirectoryPath,
+ resolvePath,
+} from "./path";
+
+export function getPnpApi(path: string) {
+ if (typeof process.versions.pnp === "undefined") {
+ return;
+ }
+
+ const { findPnpApi } = require("module");
+ if (findPnpApi) {
+ return findPnpApi(`${path}/`);
+ }
+}
+
+export function getPnpApiPath(path: string): string | undefined {
+ // eslint-disable-next-line no-null/no-null
+ return getPnpApi(path)?.resolveRequest("pnpapi", /*issuer*/ null);
+}
+
+export function getPnpTypeRoots(currentDirectory: string) {
+ const pnpApi = getPnpApi(currentDirectory);
+ if (!pnpApi) {
+ return [];
+ }
+
+ // Some TS consumers pass relative paths that aren't normalized
+ currentDirectory = resolvePath(currentDirectory);
+
+ const currentPackage = pnpApi.findPackageLocator(`${currentDirectory}/`);
+ if (!currentPackage) {
+ return [];
+ }
+
+ const { packageDependencies } = pnpApi.getPackageInformation(currentPackage);
+
+ const typeRoots: string[] = [];
+ for (const [name, referencish] of Array.from<any>(packageDependencies.entries())) {
+ // eslint-disable-next-line no-null/no-null
+ if (name.startsWith(`@types/`) && referencish !== null) {
+ const dependencyLocator = pnpApi.getLocator(name, referencish);
+ const { packageLocation } = pnpApi.getPackageInformation(dependencyLocator);
+
+ typeRoots.push(getDirectoryPath(packageLocation));
+ }
+ }
+
+ return typeRoots;
+}
+
+export function isImportablePathPnp(fromPath: string, toPath: string): boolean {
+ const pnpApi = getPnpApi(fromPath);
+
+ const fromLocator = pnpApi.findPackageLocator(fromPath);
+ const toLocator = pnpApi.findPackageLocator(toPath);
+
+ // eslint-disable-next-line no-null/no-null
+ if (toLocator === null) {
+ return false;
+ }
+
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ const toReference = fromInfo.packageDependencies.get(toLocator.name);
+
+ if (toReference) {
+ return toReference === toLocator.reference;
+ }
+
+ // Aliased dependencies
+ for (const reference of fromInfo.packageDependencies.values()) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+}

src/compiler/sys.ts

@@ -1728,6 +1728,10 @@ export let sys: System = (() => {
  }
 
  function isFileSystemCaseSensitive(): boolean {
+ // The PnP runtime is always case-sensitive
+ if (typeof process.versions.pnp !== `undefined`) {
+ return true;
+ }
  // win32\win64 are case insensitive platforms
  if (platform === "win32" || platform === "win64") {
  return false;

src/compiler/utilities.ts

@@ -10230,6 +10230,15 @@ export interface NodeModulePathParts {
  readonly packageRootIndex: number;
  readonly fileNameIndex: number;
 }
+
+/** @internal */
+export interface PackagePathParts {
+ readonly topLevelNodeModulesIndex: undefined;
+ readonly topLevelPackageNameIndex: undefined;
+ readonly packageRootIndex: number;
+ readonly fileNameIndex: number;
+}
+
 /** @internal */
 export function getNodeModulePathParts(fullPath: string): NodeModulePathParts | undefined {
  // If fullPath can't be valid module file within node_modules, returns undefined.

src/compiler/moduleNameResolver.ts

@@ -110,6 +110,10 @@ import {
  versionMajorMinor,
  VersionRange,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+ getPnpTypeRoots,
+} from "./pnp";
 
 /** @internal */
 export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void {
@@ -471,7 +475,7 @@ export function getEffectiveTypeRoots(options: CompilerOptions, host: GetEffecti
  * Returns the path to every node_modules/@types directory from some ancestor directory.
  * Returns undefined if there are none.
  */
-function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+function getNodeModulesTypeRoots(currentDirectory: string) {
  let typeRoots: string[] | undefined;
  forEachAncestorDirectory(normalizePath(currentDirectory), directory => {
  const atTypes = combinePaths(directory, nodeModulesAtTypes);
@@ -486,6 +490,18 @@ function arePathsEqual(path1: string, path2: string, host: ModuleResolutionHost)
  return comparePaths(path1, path2, !useCaseSensitiveFileNames) === Comparison.EqualTo;
 }
 
+function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+ const nmTypes = getNodeModulesTypeRoots(currentDirectory);
+ const pnpTypes = getPnpTypeRoots(currentDirectory);
+
+ if (nmTypes?.length) {
+ return [...nmTypes, ...pnpTypes];
+ }
+ else if (pnpTypes.length) {
+ return pnpTypes;
+ }
+}
+
 function getOriginalAndResolvedFileName(fileName: string, host: ModuleResolutionHost, traceEnabled: boolean) {
  const resolvedFileName = realPath(fileName, host, traceEnabled);
  const pathsAreEqual = arePathsEqual(fileName, resolvedFileName, host);
@@ -770,6 +786,18 @@ export function resolvePackageNameToPackageJson(
 ): PackageJsonInfo | undefined {
  const moduleResolutionState = getTemporaryModuleResolutionState(cache?.getPackageJsonInfoCache(), host, options);
 
+ const pnpapi = getPnpApi(containingDirectory);
+ if (pnpapi) {
+ try {
+ const resolution = pnpapi.resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ const candidate = normalizeSlashes(resolution).replace(/\/$/, "");
+ return getPackageJsonInfo(candidate, /*onlyRecordFailures*/ false, moduleResolutionState);
+ }
+ catch {
+ return;
+ }
+ }
+
  return forEachAncestorDirectory(containingDirectory, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const nodeModulesFolder = combinePaths(ancestorDirectory, "node_modules");
@@ -2938,7 +2966,16 @@ function loadModuleFromNearestNodeModulesDirectoryWorker(extensions: Extensions,
  }
 
  function lookup(extensions: Extensions) {
- return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
+ const issuer = normalizeSlashes(directory);
+ if (getPnpApi(issuer)) {
+ const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, issuer, redirectedReference, state);
+ if (resolutionFromCache) {
+ return resolutionFromCache;
+ }
+ return toSearchResult(loadModuleFromImmediateNodeModulesDirectoryPnP(extensions, moduleName, issuer, state, typesScopeOnly, cache, redirectedReference));
+ }
+
+ return forEachAncestorDirectory(issuer, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, ancestorDirectory, redirectedReference, state);
  if (resolutionFromCache) {
@@ -2977,11 +3014,34 @@ function loadModuleFromImmediateNodeModulesDirectory(extensions: Extensions, mod
  }
 }
 
+function loadModuleFromImmediateNodeModulesDirectoryPnP(extensions: Extensions, moduleName: string, directory: string, state: ModuleResolutionState, typesScopeOnly: boolean, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const issuer = normalizeSlashes(directory);
+
+ if (!typesScopeOnly) {
+ const packageResult = tryLoadModuleUsingPnpResolution(extensions, moduleName, issuer, state, cache, redirectedReference);
+ if (packageResult) {
+ return packageResult;
+ }
+ }
+
+ if (extensions & Extensions.Declaration) {
+ return tryLoadModuleUsingPnpResolution(Extensions.Declaration, `@types/${mangleScopedPackageNameWithTrace(moduleName, state)}`, issuer, state, cache, redirectedReference);
+ }
+}
+
 function loadModuleFromSpecificNodeModulesDirectory(extensions: Extensions, moduleName: string, nodeModulesDirectory: string, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
  const candidate = normalizePath(combinePaths(nodeModulesDirectory, moduleName));
  const { packageName, rest } = parsePackageName(moduleName);
  const packageDirectory = combinePaths(nodeModulesDirectory, packageName);
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, nodeModulesDirectoryExists, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
 
+function loadModuleFromPnpResolution(extensions: Extensions, packageDirectory: string, rest: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const candidate = normalizePath(combinePaths(packageDirectory, rest));
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, /*nodeModulesDirectoryExists*/ true, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
+
+function loadModuleFromSpecificNodeModulesDirectoryImpl(extensions: Extensions, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined, candidate: string, rest: string, packageDirectory: string): Resolved | undefined {
  let rootPackageInfo: PackageJsonInfo | undefined;
  // First look for a nested package.json, as in `node_modules/foo/bar/package.json`.
  let packageInfo = getPackageJsonInfo(candidate, !nodeModulesDirectoryExists, state);
@@ -3306,3 +3366,22 @@ function useCaseSensitiveFileNames(state: ModuleResolutionState) {
  typeof state.host.useCaseSensitiveFileNames === "boolean" ? state.host.useCaseSensitiveFileNames :
  state.host.useCaseSensitiveFileNames();
 }
+
+function loadPnpPackageResolution(packageName: string, containingDirectory: string) {
+ try {
+ const resolution = getPnpApi(containingDirectory).resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ return normalizeSlashes(resolution).replace(/\/$/, "");
+ }
+ catch {
+ // Nothing to do
+ }
+}
+
+function tryLoadModuleUsingPnpResolution(extensions: Extensions, moduleName: string, containingDirectory: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined) {
+ const { packageName, rest } = parsePackageName(moduleName);
+
+ const packageResolution = loadPnpPackageResolution(packageName, containingDirectory);
+ return packageResolution
+ ? loadModuleFromPnpResolution(extensions, packageResolution, rest, state, cache, redirectedReference)
+ : undefined;
+}

src/compiler/moduleSpecifiers.ts

@@ -84,6 +84,7 @@ import {
  NodeFlags,
  NodeModulePathParts,
  normalizePath,
+ PackagePathParts,
  Path,
  pathContainsNodeModules,
  pathIsBareSpecifier,
@@ -110,6 +111,9 @@ import {
  TypeChecker,
  UserPreferences,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+} from "./pnp";
 
 // Used by importFixes, getEditsForFileRename, and declaration emit to synthesize import module specifiers.
 
@@ -641,7 +645,17 @@ function getAllModulePathsWorker(importingFileName: Path, importedFileName: stri
  host,
  /*preferSymlinks*/ true,
  (path, isRedirect) => {
- const isInNodeModules = pathContainsNodeModules(path);
+ let isInNodeModules = pathContainsNodeModules(path);
+
+ const pnpapi = getPnpApi(path);
+ if (!isInNodeModules && pnpapi) {
+ const fromLocator = pnpapi.findPackageLocator(importingFileName);
+ const toLocator = pnpapi.findPackageLocator(path);
+ if (fromLocator && toLocator && fromLocator !== toLocator) {
+ isInNodeModules = true;
+ }
+ }
+
  allFileNames.set(path, { path: getCanonicalFileName(path), isRedirect, isInNodeModules });
  importedFileFromNodeModules = importedFileFromNodeModules || isInNodeModules;
  // don't return value, so we collect everything
@@ -907,7 +921,51 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  if (!host.fileExists || !host.readFile) {
  return undefined;
  }
- const parts: NodeModulePathParts = getNodeModulePathParts(path)!;
+ let parts: NodeModulePathParts | PackagePathParts | undefined = getNodeModulePathParts(path);
+
+ let pnpPackageName: string | undefined;
+
+ const pnpApi = getPnpApi(path);
+ if (pnpApi) {
+ const fromLocator = pnpApi.findPackageLocator(importingSourceFile.fileName);
+ const toLocator = pnpApi.findPackageLocator(path);
+
+ // Don't use the package name when the imported file is inside
+ // the source directory (prefer a relative path instead)
+ if (fromLocator === toLocator) {
+ return undefined;
+ }
+
+ if (fromLocator && toLocator) {
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ if (toLocator.reference === fromInfo.packageDependencies.get(toLocator.name)) {
+ pnpPackageName = toLocator.name;
+ }
+ else {
+ // Aliased dependencies
+ for (const [name, reference] of fromInfo.packageDependencies) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ pnpPackageName = name;
+ break;
+ }
+ }
+ }
+ }
+
+ if (!parts) {
+ const toInfo = pnpApi.getPackageInformation(toLocator);
+ parts = {
+ topLevelNodeModulesIndex: undefined,
+ topLevelPackageNameIndex: undefined,
+ // The last character from packageLocation is the trailing "/", we want to point to it
+ packageRootIndex: toInfo.packageLocation.length - 1,
+ fileNameIndex: path.lastIndexOf(`/`),
+ };
+ }
+ }
+ }
+
  if (!parts) {
  return undefined;
  }
@@ -952,19 +1010,26 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  return undefined;
  }
 
- const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
- // Get a path that's relative to node_modules or the importing file's path
- // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
- const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
- if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
- return undefined;
+ // If PnP is enabled the node_modules entries we'll get will always be relevant even if they
+ // are located in a weird path apparently outside of the source directory
+ if (typeof process.versions.pnp === "undefined") {
+ const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
+ // Get a path that's relative to node_modules or the importing file's path
+ // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
+ const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
+ if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
+ return undefined;
+ }
  }
 
  // If the module was found in @types, get the actual Node package name
- const nodeModulesDirectoryName = moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = typeof pnpPackageName !== "undefined"
+ ? pnpPackageName + moduleSpecifier.substring(parts.packageRootIndex)
+ : moduleSpecifier.substring(parts.topLevelPackageNameIndex! + 1);
+
+ const packageNameFromPath = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
  // For classic resolution, only allow importing from node_modules/@types, not other node_modules
- return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageName === nodeModulesDirectoryName ? undefined : packageName;
+ return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageNameFromPath === nodeModulesDirectoryName ? undefined : packageNameFromPath;
 
  function tryDirectoryWithPackageJson(packageRootIndex: number): { moduleFileToTry: string; packageRootPath?: string; blockedByExports?: true; verbatimFromExports?: true; } {
  const packageRootPath = path.substring(0, packageRootIndex);
@@ -979,8 +1044,8 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  // The package name that we found in node_modules could be different from the package
  // name in the package.json content via url/filepath dependency specifiers. We need to
  // use the actual directory name, so don't look at `packageJsonContent.name` here.
- const nodeModulesDirectoryName = packageRootPath.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = packageRootPath.substring(parts!.topLevelPackageNameIndex! + 1);
+ const packageName = getPackageNameFromTypesPackageName(pnpPackageName ? pnpPackageName : nodeModulesDirectoryName);
  const conditions = getConditions(options, importMode === ModuleKind.ESNext);
  const fromExports = packageJsonContent.exports
  ? tryGetModuleNameFromExports(options, path, packageRootPath, packageName, packageJsonContent.exports, conditions)
@@ -1046,7 +1111,7 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  }
  else {
  // No package.json exists; an index.js will still resolve as the package name
- const fileName = getCanonicalFileName(moduleFileToTry.substring(parts.packageRootIndex + 1));
+ const fileName = getCanonicalFileName(moduleFileToTry.substring(parts!.packageRootIndex + 1));
  if (fileName === "index.d.ts" || fileName === "index.js" || fileName === "index.ts" || fileName === "index.tsx") {
  return { moduleFileToTry, packageRootPath };
  }

src/compiler/pnp.ts

@@ -0,0 +1,80 @@
+import {
+ getDirectoryPath,
+ resolvePath,
+} from "./path";
+
+export function getPnpApi(path: string) {
+ if (typeof process.versions.pnp === "undefined") {
+ return;
+ }
+
+ const { findPnpApi } = require("module");
+ if (findPnpApi) {
+ return findPnpApi(`${path}/`);
+ }
+}
+
+export function getPnpApiPath(path: string): string | undefined {
+ // eslint-disable-next-line no-null/no-null
+ return getPnpApi(path)?.resolveRequest("pnpapi", /*issuer*/ null);
+}
+
+export function getPnpTypeRoots(currentDirectory: string) {
+ const pnpApi = getPnpApi(currentDirectory);
+ if (!pnpApi) {
+ return [];
+ }
+
+ // Some TS consumers pass relative paths that aren't normalized
+ currentDirectory = resolvePath(currentDirectory);
+
+ const currentPackage = pnpApi.findPackageLocator(`${currentDirectory}/`);
+ if (!currentPackage) {
+ return [];
+ }
+
+ const { packageDependencies } = pnpApi.getPackageInformation(currentPackage);
+
+ const typeRoots: string[] = [];
+ for (const [name, referencish] of Array.from<any>(packageDependencies.entries())) {
+ // eslint-disable-next-line no-null/no-null
+ if (name.startsWith(`@types/`) && referencish !== null) {
+ const dependencyLocator = pnpApi.getLocator(name, referencish);
+ const { packageLocation } = pnpApi.getPackageInformation(dependencyLocator);
+
+ typeRoots.push(getDirectoryPath(packageLocation));
+ }
+ }
+
+ return typeRoots;
+}
+
+export function isImportablePathPnp(fromPath: string, toPath: string): boolean {
+ const pnpApi = getPnpApi(fromPath);
+
+ const fromLocator = pnpApi.findPackageLocator(fromPath);
+ const toLocator = pnpApi.findPackageLocator(toPath);
+
+ // eslint-disable-next-line no-null/no-null
+ if (toLocator === null) {
+ return false;
+ }
+
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ const toReference = fromInfo.packageDependencies.get(toLocator.name);
+
+ if (toReference) {
+ return toReference === toLocator.reference;
+ }
+
+ // Aliased dependencies
+ for (const reference of fromInfo.packageDependencies.values()) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+}

src/compiler/sys.ts

@@ -1728,6 +1728,10 @@ export let sys: System = (() => {
  }
 
  function isFileSystemCaseSensitive(): boolean {
+ // The PnP runtime is always case-sensitive
+ if (typeof process.versions.pnp !== `undefined`) {
+ return true;
+ }
  // win32\win64 are case insensitive platforms
  if (platform === "win32" || platform === "win64") {
  return false;

src/compiler/utilities.ts

@@ -10230,6 +10230,15 @@ export interface NodeModulePathParts {
  readonly packageRootIndex: number;
  readonly fileNameIndex: number;
 }
+
+/** @internal */
+export interface PackagePathParts {
+ readonly topLevelNodeModulesIndex: undefined;
+ readonly topLevelPackageNameIndex: undefined;
+ readonly packageRootIndex: number;
+ readonly fileNameIndex: number;
+}
+
 /** @internal */
 export function getNodeModulePathParts(fullPath: string): NodeModulePathParts | undefined {
  // If fullPath can't be valid module file within node_modules, returns undefined.

src/compiler/moduleNameResolver.ts

@@ -110,6 +110,10 @@ import {
  versionMajorMinor,
  VersionRange,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+ getPnpTypeRoots,
+} from "./pnp";
 
 /** @internal */
 export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void {
@@ -471,7 +475,7 @@ export function getEffectiveTypeRoots(options: CompilerOptions, host: GetEffecti
  * Returns the path to every node_modules/@types directory from some ancestor directory.
  * Returns undefined if there are none.
  */
-function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+function getNodeModulesTypeRoots(currentDirectory: string) {
  let typeRoots: string[] | undefined;
  forEachAncestorDirectory(normalizePath(currentDirectory), directory => {
  const atTypes = combinePaths(directory, nodeModulesAtTypes);
@@ -486,6 +490,18 @@ function arePathsEqual(path1: string, path2: string, host: ModuleResolutionHost)
  return comparePaths(path1, path2, !useCaseSensitiveFileNames) === Comparison.EqualTo;
 }
 
+function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+ const nmTypes = getNodeModulesTypeRoots(currentDirectory);
+ const pnpTypes = getPnpTypeRoots(currentDirectory);
+
+ if (nmTypes?.length) {
+ return [...nmTypes, ...pnpTypes];
+ }
+ else if (pnpTypes.length) {
+ return pnpTypes;
+ }
+}
+
 function getOriginalAndResolvedFileName(fileName: string, host: ModuleResolutionHost, traceEnabled: boolean) {
  const resolvedFileName = realPath(fileName, host, traceEnabled);
  const pathsAreEqual = arePathsEqual(fileName, resolvedFileName, host);
@@ -770,6 +786,18 @@ export function resolvePackageNameToPackageJson(
 ): PackageJsonInfo | undefined {
  const moduleResolutionState = getTemporaryModuleResolutionState(cache?.getPackageJsonInfoCache(), host, options);
 
+ const pnpapi = getPnpApi(containingDirectory);
+ if (pnpapi) {
+ try {
+ const resolution = pnpapi.resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ const candidate = normalizeSlashes(resolution).replace(/\/$/, "");
+ return getPackageJsonInfo(candidate, /*onlyRecordFailures*/ false, moduleResolutionState);
+ }
+ catch {
+ return;
+ }
+ }
+
  return forEachAncestorDirectory(containingDirectory, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const nodeModulesFolder = combinePaths(ancestorDirectory, "node_modules");
@@ -2938,7 +2966,16 @@ function loadModuleFromNearestNodeModulesDirectoryWorker(extensions: Extensions,
  }
 
  function lookup(extensions: Extensions) {
- return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
+ const issuer = normalizeSlashes(directory);
+ if (getPnpApi(issuer)) {
+ const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, issuer, redirectedReference, state);
+ if (resolutionFromCache) {
+ return resolutionFromCache;
+ }
+ return toSearchResult(loadModuleFromImmediateNodeModulesDirectoryPnP(extensions, moduleName, issuer, state, typesScopeOnly, cache, redirectedReference));
+ }
+
+ return forEachAncestorDirectory(issuer, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, ancestorDirectory, redirectedReference, state);
  if (resolutionFromCache) {
@@ -2977,11 +3014,34 @@ function loadModuleFromImmediateNodeModulesDirectory(extensions: Extensions, mod
  }
 }
 
+function loadModuleFromImmediateNodeModulesDirectoryPnP(extensions: Extensions, moduleName: string, directory: string, state: ModuleResolutionState, typesScopeOnly: boolean, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const issuer = normalizeSlashes(directory);
+
+ if (!typesScopeOnly) {
+ const packageResult = tryLoadModuleUsingPnpResolution(extensions, moduleName, issuer, state, cache, redirectedReference);
+ if (packageResult) {
+ return packageResult;
+ }
+ }
+
+ if (extensions & Extensions.Declaration) {
+ return tryLoadModuleUsingPnpResolution(Extensions.Declaration, `@types/${mangleScopedPackageNameWithTrace(moduleName, state)}`, issuer, state, cache, redirectedReference);
+ }
+}
+
 function loadModuleFromSpecificNodeModulesDirectory(extensions: Extensions, moduleName: string, nodeModulesDirectory: string, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
  const candidate = normalizePath(combinePaths(nodeModulesDirectory, moduleName));
  const { packageName, rest } = parsePackageName(moduleName);
  const packageDirectory = combinePaths(nodeModulesDirectory, packageName);
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, nodeModulesDirectoryExists, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
 
+function loadModuleFromPnpResolution(extensions: Extensions, packageDirectory: string, rest: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const candidate = normalizePath(combinePaths(packageDirectory, rest));
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, /*nodeModulesDirectoryExists*/ true, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
+
+function loadModuleFromSpecificNodeModulesDirectoryImpl(extensions: Extensions, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined, candidate: string, rest: string, packageDirectory: string): Resolved | undefined {
  let rootPackageInfo: PackageJsonInfo | undefined;
  // First look for a nested package.json, as in `node_modules/foo/bar/package.json`.
  let packageInfo = getPackageJsonInfo(candidate, !nodeModulesDirectoryExists, state);
@@ -3306,3 +3366,22 @@ function useCaseSensitiveFileNames(state: ModuleResolutionState) {
  typeof state.host.useCaseSensitiveFileNames === "boolean" ? state.host.useCaseSensitiveFileNames :
  state.host.useCaseSensitiveFileNames();
 }
+
+function loadPnpPackageResolution(packageName: string, containingDirectory: string) {
+ try {
+ const resolution = getPnpApi(containingDirectory).resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ return normalizeSlashes(resolution).replace(/\/$/, "");
+ }
+ catch {
+ // Nothing to do
+ }
+}
+
+function tryLoadModuleUsingPnpResolution(extensions: Extensions, moduleName: string, containingDirectory: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined) {
+ const { packageName, rest } = parsePackageName(moduleName);
+
+ const packageResolution = loadPnpPackageResolution(packageName, containingDirectory);
+ return packageResolution
+ ? loadModuleFromPnpResolution(extensions, packageResolution, rest, state, cache, redirectedReference)
+ : undefined;
+}

src/compiler/moduleSpecifiers.ts

@@ -84,6 +84,7 @@ import {
  NodeFlags,
  NodeModulePathParts,
  normalizePath,
+ PackagePathParts,
  Path,
  pathContainsNodeModules,
  pathIsBareSpecifier,
@@ -110,6 +111,9 @@ import {
  TypeChecker,
  UserPreferences,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+} from "./pnp";
 
 // Used by importFixes, getEditsForFileRename, and declaration emit to synthesize import module specifiers.
 
@@ -641,7 +645,17 @@ function getAllModulePathsWorker(importingFileName: Path, importedFileName: stri
  host,
  /*preferSymlinks*/ true,
  (path, isRedirect) => {
- const isInNodeModules = pathContainsNodeModules(path);
+ let isInNodeModules = pathContainsNodeModules(path);
+
+ const pnpapi = getPnpApi(path);
+ if (!isInNodeModules && pnpapi) {
+ const fromLocator = pnpapi.findPackageLocator(importingFileName);
+ const toLocator = pnpapi.findPackageLocator(path);
+ if (fromLocator && toLocator && fromLocator !== toLocator) {
+ isInNodeModules = true;
+ }
+ }
+
  allFileNames.set(path, { path: getCanonicalFileName(path), isRedirect, isInNodeModules });
  importedFileFromNodeModules = importedFileFromNodeModules || isInNodeModules;
  // don't return value, so we collect everything
@@ -907,7 +921,51 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  if (!host.fileExists || !host.readFile) {
  return undefined;
  }
- const parts: NodeModulePathParts = getNodeModulePathParts(path)!;
+ let parts: NodeModulePathParts | PackagePathParts | undefined = getNodeModulePathParts(path);
+
+ let pnpPackageName: string | undefined;
+
+ const pnpApi = getPnpApi(path);
+ if (pnpApi) {
+ const fromLocator = pnpApi.findPackageLocator(importingSourceFile.fileName);
+ const toLocator = pnpApi.findPackageLocator(path);
+
+ // Don't use the package name when the imported file is inside
+ // the source directory (prefer a relative path instead)
+ if (fromLocator === toLocator) {
+ return undefined;
+ }
+
+ if (fromLocator && toLocator) {
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ if (toLocator.reference === fromInfo.packageDependencies.get(toLocator.name)) {
+ pnpPackageName = toLocator.name;
+ }
+ else {
+ // Aliased dependencies
+ for (const [name, reference] of fromInfo.packageDependencies) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ pnpPackageName = name;
+ break;
+ }
+ }
+ }
+ }
+
+ if (!parts) {
+ const toInfo = pnpApi.getPackageInformation(toLocator);
+ parts = {
+ topLevelNodeModulesIndex: undefined,
+ topLevelPackageNameIndex: undefined,
+ // The last character from packageLocation is the trailing "/", we want to point to it
+ packageRootIndex: toInfo.packageLocation.length - 1,
+ fileNameIndex: path.lastIndexOf(`/`),
+ };
+ }
+ }
+ }
+
  if (!parts) {
  return undefined;
  }
@@ -952,19 +1010,26 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  return undefined;
  }
 
- const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
- // Get a path that's relative to node_modules or the importing file's path
- // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
- const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
- if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
- return undefined;
+ // If PnP is enabled the node_modules entries we'll get will always be relevant even if they
+ // are located in a weird path apparently outside of the source directory
+ if (typeof process.versions.pnp === "undefined") {
+ const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
+ // Get a path that's relative to node_modules or the importing file's path
+ // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
+ const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
+ if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
+ return undefined;
+ }
  }
 
  // If the module was found in @types, get the actual Node package name
- const nodeModulesDirectoryName = moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = typeof pnpPackageName !== "undefined"
+ ? pnpPackageName + moduleSpecifier.substring(parts.packageRootIndex)
+ : moduleSpecifier.substring(parts.topLevelPackageNameIndex! + 1);
+
+ const packageNameFromPath = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
  // For classic resolution, only allow importing from node_modules/@types, not other node_modules
- return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageName === nodeModulesDirectoryName ? undefined : packageName;
+ return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageNameFromPath === nodeModulesDirectoryName ? undefined : packageNameFromPath;
 
  function tryDirectoryWithPackageJson(packageRootIndex: number): { moduleFileToTry: string; packageRootPath?: string; blockedByExports?: true; verbatimFromExports?: true; } {
  const packageRootPath = path.substring(0, packageRootIndex);
@@ -979,8 +1044,8 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  // The package name that we found in node_modules could be different from the package
  // name in the package.json content via url/filepath dependency specifiers. We need to
  // use the actual directory name, so don't look at `packageJsonContent.name` here.
- const nodeModulesDirectoryName = packageRootPath.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = packageRootPath.substring(parts!.topLevelPackageNameIndex! + 1);
+ const packageName = getPackageNameFromTypesPackageName(pnpPackageName ? pnpPackageName : nodeModulesDirectoryName);
  const conditions = getConditions(options, importMode === ModuleKind.ESNext);
  const fromExports = packageJsonContent.exports
  ? tryGetModuleNameFromExports(options, path, packageRootPath, packageName, packageJsonContent.exports, conditions)
@@ -1046,7 +1111,7 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  }
  else {
  // No package.json exists; an index.js will still resolve as the package name
- const fileName = getCanonicalFileName(moduleFileToTry.substring(parts.packageRootIndex + 1));
+ const fileName = getCanonicalFileName(moduleFileToTry.substring(parts!.packageRootIndex + 1));
  if (fileName === "index.d.ts" || fileName === "index.js" || fileName === "index.ts" || fileName === "index.tsx") {
  return { moduleFileToTry, packageRootPath };
  }

src/compiler/pnp.ts

@@ -0,0 +1,80 @@
+import {
+ getDirectoryPath,
+ resolvePath,
+} from "./path";
+
+export function getPnpApi(path: string) {
+ if (typeof process.versions.pnp === "undefined") {
+ return;
+ }
+
+ const { findPnpApi } = require("module");
+ if (findPnpApi) {
+ return findPnpApi(`${path}/`);
+ }
+}
+
+export function getPnpApiPath(path: string): string | undefined {
+ // eslint-disable-next-line no-null/no-null
+ return getPnpApi(path)?.resolveRequest("pnpapi", /*issuer*/ null);
+}
+
+export function getPnpTypeRoots(currentDirectory: string) {
+ const pnpApi = getPnpApi(currentDirectory);
+ if (!pnpApi) {
+ return [];
+ }
+
+ // Some TS consumers pass relative paths that aren't normalized
+ currentDirectory = resolvePath(currentDirectory);
+
+ const currentPackage = pnpApi.findPackageLocator(`${currentDirectory}/`);
+ if (!currentPackage) {
+ return [];
+ }
+
+ const { packageDependencies } = pnpApi.getPackageInformation(currentPackage);
+
+ const typeRoots: string[] = [];
+ for (const [name, referencish] of Array.from<any>(packageDependencies.entries())) {
+ // eslint-disable-next-line no-null/no-null
+ if (name.startsWith(`@types/`) && referencish !== null) {
+ const dependencyLocator = pnpApi.getLocator(name, referencish);
+ const { packageLocation } = pnpApi.getPackageInformation(dependencyLocator);
+
+ typeRoots.push(getDirectoryPath(packageLocation));
+ }
+ }
+
+ return typeRoots;
+}
+
+export function isImportablePathPnp(fromPath: string, toPath: string): boolean {
+ const pnpApi = getPnpApi(fromPath);
+
+ const fromLocator = pnpApi.findPackageLocator(fromPath);
+ const toLocator = pnpApi.findPackageLocator(toPath);
+
+ // eslint-disable-next-line no-null/no-null
+ if (toLocator === null) {
+ return false;
+ }
+
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ const toReference = fromInfo.packageDependencies.get(toLocator.name);
+
+ if (toReference) {
+ return toReference === toLocator.reference;
+ }
+
+ // Aliased dependencies
+ for (const reference of fromInfo.packageDependencies.values()) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+}

src/compiler/sys.ts

@@ -1728,6 +1728,10 @@ export let sys: System = (() => {
  }
 
  function isFileSystemCaseSensitive(): boolean {
+ // The PnP runtime is always case-sensitive
+ if (typeof process.versions.pnp !== `undefined`) {
+ return true;
+ }
  // win32\win64 are case insensitive platforms
  if (platform === "win32" || platform === "win64") {
  return false;

src/compiler/utilities.ts

@@ -10230,6 +10230,15 @@ export interface NodeModulePathParts {
  readonly packageRootIndex: number;
  readonly fileNameIndex: number;
 }
+
+/** @internal */
+export interface PackagePathParts {
+ readonly topLevelNodeModulesIndex: undefined;
+ readonly topLevelPackageNameIndex: undefined;
+ readonly packageRootIndex: number;
+ readonly fileNameIndex: number;
+}
+
 /** @internal */
 export function getNodeModulePathParts(fullPath: string): NodeModulePathParts | undefined {
  // If fullPath can't be valid module file within node_modules, returns undefined.

src/compiler/moduleNameResolver.ts

@@ -110,6 +110,10 @@ import {
  versionMajorMinor,
  VersionRange,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+ getPnpTypeRoots,
+} from "./pnp";
 
 /** @internal */
 export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void {
@@ -471,7 +475,7 @@ export function getEffectiveTypeRoots(options: CompilerOptions, host: GetEffecti
  * Returns the path to every node_modules/@types directory from some ancestor directory.
  * Returns undefined if there are none.
  */
-function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+function getNodeModulesTypeRoots(currentDirectory: string) {
  let typeRoots: string[] | undefined;
  forEachAncestorDirectory(normalizePath(currentDirectory), directory => {
  const atTypes = combinePaths(directory, nodeModulesAtTypes);
@@ -486,6 +490,18 @@ function arePathsEqual(path1: string, path2: string, host: ModuleResolutionHost)
  return comparePaths(path1, path2, !useCaseSensitiveFileNames) === Comparison.EqualTo;
 }
 
+function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+ const nmTypes = getNodeModulesTypeRoots(currentDirectory);
+ const pnpTypes = getPnpTypeRoots(currentDirectory);
+
+ if (nmTypes?.length) {
+ return [...nmTypes, ...pnpTypes];
+ }
+ else if (pnpTypes.length) {
+ return pnpTypes;
+ }
+}
+
 function getOriginalAndResolvedFileName(fileName: string, host: ModuleResolutionHost, traceEnabled: boolean) {
  const resolvedFileName = realPath(fileName, host, traceEnabled);
  const pathsAreEqual = arePathsEqual(fileName, resolvedFileName, host);
@@ -770,6 +786,18 @@ export function resolvePackageNameToPackageJson(
 ): PackageJsonInfo | undefined {
  const moduleResolutionState = getTemporaryModuleResolutionState(cache?.getPackageJsonInfoCache(), host, options);
 
+ const pnpapi = getPnpApi(containingDirectory);
+ if (pnpapi) {
+ try {
+ const resolution = pnpapi.resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ const candidate = normalizeSlashes(resolution).replace(/\/$/, "");
+ return getPackageJsonInfo(candidate, /*onlyRecordFailures*/ false, moduleResolutionState);
+ }
+ catch {
+ return;
+ }
+ }
+
  return forEachAncestorDirectory(containingDirectory, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const nodeModulesFolder = combinePaths(ancestorDirectory, "node_modules");
@@ -2938,7 +2966,16 @@ function loadModuleFromNearestNodeModulesDirectoryWorker(extensions: Extensions,
  }
 
  function lookup(extensions: Extensions) {
- return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
+ const issuer = normalizeSlashes(directory);
+ if (getPnpApi(issuer)) {
+ const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, issuer, redirectedReference, state);
+ if (resolutionFromCache) {
+ return resolutionFromCache;
+ }
+ return toSearchResult(loadModuleFromImmediateNodeModulesDirectoryPnP(extensions, moduleName, issuer, state, typesScopeOnly, cache, redirectedReference));
+ }
+
+ return forEachAncestorDirectory(issuer, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, ancestorDirectory, redirectedReference, state);
  if (resolutionFromCache) {
@@ -2977,11 +3014,34 @@ function loadModuleFromImmediateNodeModulesDirectory(extensions: Extensions, mod
  }
 }
 
+function loadModuleFromImmediateNodeModulesDirectoryPnP(extensions: Extensions, moduleName: string, directory: string, state: ModuleResolutionState, typesScopeOnly: boolean, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const issuer = normalizeSlashes(directory);
+
+ if (!typesScopeOnly) {
+ const packageResult = tryLoadModuleUsingPnpResolution(extensions, moduleName, issuer, state, cache, redirectedReference);
+ if (packageResult) {
+ return packageResult;
+ }
+ }
+
+ if (extensions & Extensions.Declaration) {
+ return tryLoadModuleUsingPnpResolution(Extensions.Declaration, `@types/${mangleScopedPackageNameWithTrace(moduleName, state)}`, issuer, state, cache, redirectedReference);
+ }
+}
+
 function loadModuleFromSpecificNodeModulesDirectory(extensions: Extensions, moduleName: string, nodeModulesDirectory: string, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
  const candidate = normalizePath(combinePaths(nodeModulesDirectory, moduleName));
  const { packageName, rest } = parsePackageName(moduleName);
  const packageDirectory = combinePaths(nodeModulesDirectory, packageName);
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, nodeModulesDirectoryExists, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
 
+function loadModuleFromPnpResolution(extensions: Extensions, packageDirectory: string, rest: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const candidate = normalizePath(combinePaths(packageDirectory, rest));
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, /*nodeModulesDirectoryExists*/ true, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
+
+function loadModuleFromSpecificNodeModulesDirectoryImpl(extensions: Extensions, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined, candidate: string, rest: string, packageDirectory: string): Resolved | undefined {
  let rootPackageInfo: PackageJsonInfo | undefined;
  // First look for a nested package.json, as in `node_modules/foo/bar/package.json`.
  let packageInfo = getPackageJsonInfo(candidate, !nodeModulesDirectoryExists, state);
@@ -3306,3 +3366,22 @@ function useCaseSensitiveFileNames(state: ModuleResolutionState) {
  typeof state.host.useCaseSensitiveFileNames === "boolean" ? state.host.useCaseSensitiveFileNames :
  state.host.useCaseSensitiveFileNames();
 }
+
+function loadPnpPackageResolution(packageName: string, containingDirectory: string) {
+ try {
+ const resolution = getPnpApi(containingDirectory).resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ return normalizeSlashes(resolution).replace(/\/$/, "");
+ }
+ catch {
+ // Nothing to do
+ }
+}
+
+function tryLoadModuleUsingPnpResolution(extensions: Extensions, moduleName: string, containingDirectory: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined) {
+ const { packageName, rest } = parsePackageName(moduleName);
+
+ const packageResolution = loadPnpPackageResolution(packageName, containingDirectory);
+ return packageResolution
+ ? loadModuleFromPnpResolution(extensions, packageResolution, rest, state, cache, redirectedReference)
+ : undefined;
+}

src/compiler/moduleSpecifiers.ts

@@ -84,6 +84,7 @@ import {
  NodeFlags,
  NodeModulePathParts,
  normalizePath,
+ PackagePathParts,
  Path,
  pathContainsNodeModules,
  pathIsBareSpecifier,
@@ -110,6 +111,9 @@ import {
  TypeChecker,
  UserPreferences,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+} from "./pnp";
 
 // Used by importFixes, getEditsForFileRename, and declaration emit to synthesize import module specifiers.
 
@@ -641,7 +645,17 @@ function getAllModulePathsWorker(importingFileName: Path, importedFileName: stri
  host,
  /*preferSymlinks*/ true,
  (path, isRedirect) => {
- const isInNodeModules = pathContainsNodeModules(path);
+ let isInNodeModules = pathContainsNodeModules(path);
+
+ const pnpapi = getPnpApi(path);
+ if (!isInNodeModules && pnpapi) {
+ const fromLocator = pnpapi.findPackageLocator(importingFileName);
+ const toLocator = pnpapi.findPackageLocator(path);
+ if (fromLocator && toLocator && fromLocator !== toLocator) {
+ isInNodeModules = true;
+ }
+ }
+
  allFileNames.set(path, { path: getCanonicalFileName(path), isRedirect, isInNodeModules });
  importedFileFromNodeModules = importedFileFromNodeModules || isInNodeModules;
  // don't return value, so we collect everything
@@ -907,7 +921,51 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  if (!host.fileExists || !host.readFile) {
  return undefined;
  }
- const parts: NodeModulePathParts = getNodeModulePathParts(path)!;
+ let parts: NodeModulePathParts | PackagePathParts | undefined = getNodeModulePathParts(path);
+
+ let pnpPackageName: string | undefined;
+
+ const pnpApi = getPnpApi(path);
+ if (pnpApi) {
+ const fromLocator = pnpApi.findPackageLocator(importingSourceFile.fileName);
+ const toLocator = pnpApi.findPackageLocator(path);
+
+ // Don't use the package name when the imported file is inside
+ // the source directory (prefer a relative path instead)
+ if (fromLocator === toLocator) {
+ return undefined;
+ }
+
+ if (fromLocator && toLocator) {
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ if (toLocator.reference === fromInfo.packageDependencies.get(toLocator.name)) {
+ pnpPackageName = toLocator.name;
+ }
+ else {
+ // Aliased dependencies
+ for (const [name, reference] of fromInfo.packageDependencies) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ pnpPackageName = name;
+ break;
+ }
+ }
+ }
+ }
+
+ if (!parts) {
+ const toInfo = pnpApi.getPackageInformation(toLocator);
+ parts = {
+ topLevelNodeModulesIndex: undefined,
+ topLevelPackageNameIndex: undefined,
+ // The last character from packageLocation is the trailing "/", we want to point to it
+ packageRootIndex: toInfo.packageLocation.length - 1,
+ fileNameIndex: path.lastIndexOf(`/`),
+ };
+ }
+ }
+ }
+
  if (!parts) {
  return undefined;
  }
@@ -952,19 +1010,26 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  return undefined;
  }
 
- const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
- // Get a path that's relative to node_modules or the importing file's path
- // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
- const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
- if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
- return undefined;
+ // If PnP is enabled the node_modules entries we'll get will always be relevant even if they
+ // are located in a weird path apparently outside of the source directory
+ if (typeof process.versions.pnp === "undefined") {
+ const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
+ // Get a path that's relative to node_modules or the importing file's path
+ // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
+ const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
+ if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
+ return undefined;
+ }
  }
 
  // If the module was found in @types, get the actual Node package name
- const nodeModulesDirectoryName = moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = typeof pnpPackageName !== "undefined"
+ ? pnpPackageName + moduleSpecifier.substring(parts.packageRootIndex)
+ : moduleSpecifier.substring(parts.topLevelPackageNameIndex! + 1);
+
+ const packageNameFromPath = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
  // For classic resolution, only allow importing from node_modules/@types, not other node_modules
- return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageName === nodeModulesDirectoryName ? undefined : packageName;
+ return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageNameFromPath === nodeModulesDirectoryName ? undefined : packageNameFromPath;
 
  function tryDirectoryWithPackageJson(packageRootIndex: number): { moduleFileToTry: string; packageRootPath?: string; blockedByExports?: true; verbatimFromExports?: true; } {
  const packageRootPath = path.substring(0, packageRootIndex);
@@ -979,8 +1044,8 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  // The package name that we found in node_modules could be different from the package
  // name in the package.json content via url/filepath dependency specifiers. We need to
  // use the actual directory name, so don't look at `packageJsonContent.name` here.
- const nodeModulesDirectoryName = packageRootPath.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = packageRootPath.substring(parts!.topLevelPackageNameIndex! + 1);
+ const packageName = getPackageNameFromTypesPackageName(pnpPackageName ? pnpPackageName : nodeModulesDirectoryName);
  const conditions = getConditions(options, importMode === ModuleKind.ESNext);
  const fromExports = packageJsonContent.exports
  ? tryGetModuleNameFromExports(options, path, packageRootPath, packageName, packageJsonContent.exports, conditions)
@@ -1046,7 +1111,7 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  }
  else {
  // No package.json exists; an index.js will still resolve as the package name
- const fileName = getCanonicalFileName(moduleFileToTry.substring(parts.packageRootIndex + 1));
+ const fileName = getCanonicalFileName(moduleFileToTry.substring(parts!.packageRootIndex + 1));
  if (fileName === "index.d.ts" || fileName === "index.js" || fileName === "index.ts" || fileName === "index.tsx") {
  return { moduleFileToTry, packageRootPath };
  }

src/compiler/pnp.ts

@@ -0,0 +1,80 @@
+import {
+ getDirectoryPath,
+ resolvePath,
+} from "./path";
+
+export function getPnpApi(path: string) {
+ if (typeof process.versions.pnp === "undefined") {
+ return;
+ }
+
+ const { findPnpApi } = require("module");
+ if (findPnpApi) {
+ return findPnpApi(`${path}/`);
+ }
+}
+
+export function getPnpApiPath(path: string): string | undefined {
+ // eslint-disable-next-line no-null/no-null
+ return getPnpApi(path)?.resolveRequest("pnpapi", /*issuer*/ null);
+}
+
+export function getPnpTypeRoots(currentDirectory: string) {
+ const pnpApi = getPnpApi(currentDirectory);
+ if (!pnpApi) {
+ return [];
+ }
+
+ // Some TS consumers pass relative paths that aren't normalized
+ currentDirectory = resolvePath(currentDirectory);
+
+ const currentPackage = pnpApi.findPackageLocator(`${currentDirectory}/`);
+ if (!currentPackage) {
+ return [];
+ }
+
+ const { packageDependencies } = pnpApi.getPackageInformation(currentPackage);
+
+ const typeRoots: string[] = [];
+ for (const [name, referencish] of Array.from<any>(packageDependencies.entries())) {
+ // eslint-disable-next-line no-null/no-null
+ if (name.startsWith(`@types/`) && referencish !== null) {
+ const dependencyLocator = pnpApi.getLocator(name, referencish);
+ const { packageLocation } = pnpApi.getPackageInformation(dependencyLocator);
+
+ typeRoots.push(getDirectoryPath(packageLocation));
+ }
+ }
+
+ return typeRoots;
+}
+
+export function isImportablePathPnp(fromPath: string, toPath: string): boolean {
+ const pnpApi = getPnpApi(fromPath);
+
+ const fromLocator = pnpApi.findPackageLocator(fromPath);
+ const toLocator = pnpApi.findPackageLocator(toPath);
+
+ // eslint-disable-next-line no-null/no-null
+ if (toLocator === null) {
+ return false;
+ }
+
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ const toReference = fromInfo.packageDependencies.get(toLocator.name);
+
+ if (toReference) {
+ return toReference === toLocator.reference;
+ }
+
+ // Aliased dependencies
+ for (const reference of fromInfo.packageDependencies.values()) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+}

src/compiler/sys.ts

@@ -1728,6 +1728,10 @@ export let sys: System = (() => {
  }
 
  function isFileSystemCaseSensitive(): boolean {
+ // The PnP runtime is always case-sensitive
+ if (typeof process.versions.pnp !== `undefined`) {
+ return true;
+ }
  // win32\win64 are case insensitive platforms
  if (platform === "win32" || platform === "win64") {
  return false;

src/compiler/utilities.ts

@@ -10230,6 +10230,15 @@ export interface NodeModulePathParts {
  readonly packageRootIndex: number;
  readonly fileNameIndex: number;
 }
+
+/** @internal */
+export interface PackagePathParts {
+ readonly topLevelNodeModulesIndex: undefined;
+ readonly topLevelPackageNameIndex: undefined;
+ readonly packageRootIndex: number;
+ readonly fileNameIndex: number;
+}
+
 /** @internal */
 export function getNodeModulePathParts(fullPath: string): NodeModulePathParts | undefined {
  // If fullPath can't be valid module file within node_modules, returns undefined.

src/compiler/moduleNameResolver.ts

@@ -110,6 +110,10 @@ import {
  versionMajorMinor,
  VersionRange,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+ getPnpTypeRoots,
+} from "./pnp";
 
 /** @internal */
 export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void {
@@ -471,7 +475,7 @@ export function getEffectiveTypeRoots(options: CompilerOptions, host: GetEffecti
  * Returns the path to every node_modules/@types directory from some ancestor directory.
  * Returns undefined if there are none.
  */
-function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+function getNodeModulesTypeRoots(currentDirectory: string) {
  let typeRoots: string[] | undefined;
  forEachAncestorDirectory(normalizePath(currentDirectory), directory => {
  const atTypes = combinePaths(directory, nodeModulesAtTypes);
@@ -486,6 +490,18 @@ function arePathsEqual(path1: string, path2: string, host: ModuleResolutionHost)
  return comparePaths(path1, path2, !useCaseSensitiveFileNames) === Comparison.EqualTo;
 }
 
+function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+ const nmTypes = getNodeModulesTypeRoots(currentDirectory);
+ const pnpTypes = getPnpTypeRoots(currentDirectory);
+
+ if (nmTypes?.length) {
+ return [...nmTypes, ...pnpTypes];
+ }
+ else if (pnpTypes.length) {
+ return pnpTypes;
+ }
+}
+
 function getOriginalAndResolvedFileName(fileName: string, host: ModuleResolutionHost, traceEnabled: boolean) {
  const resolvedFileName = realPath(fileName, host, traceEnabled);
  const pathsAreEqual = arePathsEqual(fileName, resolvedFileName, host);
@@ -770,6 +786,18 @@ export function resolvePackageNameToPackageJson(
 ): PackageJsonInfo | undefined {
  const moduleResolutionState = getTemporaryModuleResolutionState(cache?.getPackageJsonInfoCache(), host, options);
 
+ const pnpapi = getPnpApi(containingDirectory);
+ if (pnpapi) {
+ try {
+ const resolution = pnpapi.resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ const candidate = normalizeSlashes(resolution).replace(/\/$/, "");
+ return getPackageJsonInfo(candidate, /*onlyRecordFailures*/ false, moduleResolutionState);
+ }
+ catch {
+ return;
+ }
+ }
+
  return forEachAncestorDirectory(containingDirectory, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const nodeModulesFolder = combinePaths(ancestorDirectory, "node_modules");
@@ -2938,7 +2966,16 @@ function loadModuleFromNearestNodeModulesDirectoryWorker(extensions: Extensions,
  }
 
  function lookup(extensions: Extensions) {
- return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
+ const issuer = normalizeSlashes(directory);
+ if (getPnpApi(issuer)) {
+ const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, issuer, redirectedReference, state);
+ if (resolutionFromCache) {
+ return resolutionFromCache;
+ }
+ return toSearchResult(loadModuleFromImmediateNodeModulesDirectoryPnP(extensions, moduleName, issuer, state, typesScopeOnly, cache, redirectedReference));
+ }
+
+ return forEachAncestorDirectory(issuer, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, ancestorDirectory, redirectedReference, state);
  if (resolutionFromCache) {
@@ -2977,11 +3014,34 @@ function loadModuleFromImmediateNodeModulesDirectory(extensions: Extensions, mod
  }
 }
 
+function loadModuleFromImmediateNodeModulesDirectoryPnP(extensions: Extensions, moduleName: string, directory: string, state: ModuleResolutionState, typesScopeOnly: boolean, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const issuer = normalizeSlashes(directory);
+
+ if (!typesScopeOnly) {
+ const packageResult = tryLoadModuleUsingPnpResolution(extensions, moduleName, issuer, state, cache, redirectedReference);
+ if (packageResult) {
+ return packageResult;
+ }
+ }
+
+ if (extensions & Extensions.Declaration) {
+ return tryLoadModuleUsingPnpResolution(Extensions.Declaration, `@types/${mangleScopedPackageNameWithTrace(moduleName, state)}`, issuer, state, cache, redirectedReference);
+ }
+}
+
 function loadModuleFromSpecificNodeModulesDirectory(extensions: Extensions, moduleName: string, nodeModulesDirectory: string, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
  const candidate = normalizePath(combinePaths(nodeModulesDirectory, moduleName));
  const { packageName, rest } = parsePackageName(moduleName);
  const packageDirectory = combinePaths(nodeModulesDirectory, packageName);
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, nodeModulesDirectoryExists, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
 
+function loadModuleFromPnpResolution(extensions: Extensions, packageDirectory: string, rest: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const candidate = normalizePath(combinePaths(packageDirectory, rest));
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, /*nodeModulesDirectoryExists*/ true, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
+
+function loadModuleFromSpecificNodeModulesDirectoryImpl(extensions: Extensions, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined, candidate: string, rest: string, packageDirectory: string): Resolved | undefined {
  let rootPackageInfo: PackageJsonInfo | undefined;
  // First look for a nested package.json, as in `node_modules/foo/bar/package.json`.
  let packageInfo = getPackageJsonInfo(candidate, !nodeModulesDirectoryExists, state);
@@ -3306,3 +3366,22 @@ function useCaseSensitiveFileNames(state: ModuleResolutionState) {
  typeof state.host.useCaseSensitiveFileNames === "boolean" ? state.host.useCaseSensitiveFileNames :
  state.host.useCaseSensitiveFileNames();
 }
+
+function loadPnpPackageResolution(packageName: string, containingDirectory: string) {
+ try {
+ const resolution = getPnpApi(containingDirectory).resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ return normalizeSlashes(resolution).replace(/\/$/, "");
+ }
+ catch {
+ // Nothing to do
+ }
+}
+
+function tryLoadModuleUsingPnpResolution(extensions: Extensions, moduleName: string, containingDirectory: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined) {
+ const { packageName, rest } = parsePackageName(moduleName);
+
+ const packageResolution = loadPnpPackageResolution(packageName, containingDirectory);
+ return packageResolution
+ ? loadModuleFromPnpResolution(extensions, packageResolution, rest, state, cache, redirectedReference)
+ : undefined;
+}

src/compiler/moduleSpecifiers.ts

@@ -84,6 +84,7 @@ import {
  NodeFlags,
  NodeModulePathParts,
  normalizePath,
+ PackagePathParts,
  Path,
  pathContainsNodeModules,
  pathIsBareSpecifier,
@@ -110,6 +111,9 @@ import {
  TypeChecker,
  UserPreferences,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+} from "./pnp";
 
 // Used by importFixes, getEditsForFileRename, and declaration emit to synthesize import module specifiers.
 
@@ -641,7 +645,17 @@ function getAllModulePathsWorker(importingFileName: Path, importedFileName: stri
  host,
  /*preferSymlinks*/ true,
  (path, isRedirect) => {
- const isInNodeModules = pathContainsNodeModules(path);
+ let isInNodeModules = pathContainsNodeModules(path);
+
+ const pnpapi = getPnpApi(path);
+ if (!isInNodeModules && pnpapi) {
+ const fromLocator = pnpapi.findPackageLocator(importingFileName);
+ const toLocator = pnpapi.findPackageLocator(path);
+ if (fromLocator && toLocator && fromLocator !== toLocator) {
+ isInNodeModules = true;
+ }
+ }
+
  allFileNames.set(path, { path: getCanonicalFileName(path), isRedirect, isInNodeModules });
  importedFileFromNodeModules = importedFileFromNodeModules || isInNodeModules;
  // don't return value, so we collect everything
@@ -907,7 +921,51 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  if (!host.fileExists || !host.readFile) {
  return undefined;
  }
- const parts: NodeModulePathParts = getNodeModulePathParts(path)!;
+ let parts: NodeModulePathParts | PackagePathParts | undefined = getNodeModulePathParts(path);
+
+ let pnpPackageName: string | undefined;
+
+ const pnpApi = getPnpApi(path);
+ if (pnpApi) {
+ const fromLocator = pnpApi.findPackageLocator(importingSourceFile.fileName);
+ const toLocator = pnpApi.findPackageLocator(path);
+
+ // Don't use the package name when the imported file is inside
+ // the source directory (prefer a relative path instead)
+ if (fromLocator === toLocator) {
+ return undefined;
+ }
+
+ if (fromLocator && toLocator) {
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ if (toLocator.reference === fromInfo.packageDependencies.get(toLocator.name)) {
+ pnpPackageName = toLocator.name;
+ }
+ else {
+ // Aliased dependencies
+ for (const [name, reference] of fromInfo.packageDependencies) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ pnpPackageName = name;
+ break;
+ }
+ }
+ }
+ }
+
+ if (!parts) {
+ const toInfo = pnpApi.getPackageInformation(toLocator);
+ parts = {
+ topLevelNodeModulesIndex: undefined,
+ topLevelPackageNameIndex: undefined,
+ // The last character from packageLocation is the trailing "/", we want to point to it
+ packageRootIndex: toInfo.packageLocation.length - 1,
+ fileNameIndex: path.lastIndexOf(`/`),
+ };
+ }
+ }
+ }
+
  if (!parts) {
  return undefined;
  }
@@ -952,19 +1010,26 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  return undefined;
  }
 
- const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
- // Get a path that's relative to node_modules or the importing file's path
- // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
- const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
- if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
- return undefined;
+ // If PnP is enabled the node_modules entries we'll get will always be relevant even if they
+ // are located in a weird path apparently outside of the source directory
+ if (typeof process.versions.pnp === "undefined") {
+ const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
+ // Get a path that's relative to node_modules or the importing file's path
+ // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
+ const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
+ if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
+ return undefined;
+ }
  }
 
  // If the module was found in @types, get the actual Node package name
- const nodeModulesDirectoryName = moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = typeof pnpPackageName !== "undefined"
+ ? pnpPackageName + moduleSpecifier.substring(parts.packageRootIndex)
+ : moduleSpecifier.substring(parts.topLevelPackageNameIndex! + 1);
+
+ const packageNameFromPath = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
  // For classic resolution, only allow importing from node_modules/@types, not other node_modules
- return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageName === nodeModulesDirectoryName ? undefined : packageName;
+ return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageNameFromPath === nodeModulesDirectoryName ? undefined : packageNameFromPath;
 
  function tryDirectoryWithPackageJson(packageRootIndex: number): { moduleFileToTry: string; packageRootPath?: string; blockedByExports?: true; verbatimFromExports?: true; } {
  const packageRootPath = path.substring(0, packageRootIndex);
@@ -979,8 +1044,8 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  // The package name that we found in node_modules could be different from the package
  // name in the package.json content via url/filepath dependency specifiers. We need to
  // use the actual directory name, so don't look at `packageJsonContent.name` here.
- const nodeModulesDirectoryName = packageRootPath.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = packageRootPath.substring(parts!.topLevelPackageNameIndex! + 1);
+ const packageName = getPackageNameFromTypesPackageName(pnpPackageName ? pnpPackageName : nodeModulesDirectoryName);
  const conditions = getConditions(options, importMode === ModuleKind.ESNext);
  const fromExports = packageJsonContent.exports
  ? tryGetModuleNameFromExports(options, path, packageRootPath, packageName, packageJsonContent.exports, conditions)
@@ -1046,7 +1111,7 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  }
  else {
  // No package.json exists; an index.js will still resolve as the package name
- const fileName = getCanonicalFileName(moduleFileToTry.substring(parts.packageRootIndex + 1));
+ const fileName = getCanonicalFileName(moduleFileToTry.substring(parts!.packageRootIndex + 1));
  if (fileName === "index.d.ts" || fileName === "index.js" || fileName === "index.ts" || fileName === "index.tsx") {
  return { moduleFileToTry, packageRootPath };
  }

src/compiler/pnp.ts

@@ -0,0 +1,80 @@
+import {
+ getDirectoryPath,
+ resolvePath,
+} from "./path";
+
+export function getPnpApi(path: string) {
+ if (typeof process.versions.pnp === "undefined") {
+ return;
+ }
+
+ const { findPnpApi } = require("module");
+ if (findPnpApi) {
+ return findPnpApi(`${path}/`);
+ }
+}
+
+export function getPnpApiPath(path: string): string | undefined {
+ // eslint-disable-next-line no-null/no-null
+ return getPnpApi(path)?.resolveRequest("pnpapi", /*issuer*/ null);
+}
+
+export function getPnpTypeRoots(currentDirectory: string) {
+ const pnpApi = getPnpApi(currentDirectory);
+ if (!pnpApi) {
+ return [];
+ }
+
+ // Some TS consumers pass relative paths that aren't normalized
+ currentDirectory = resolvePath(currentDirectory);
+
+ const currentPackage = pnpApi.findPackageLocator(`${currentDirectory}/`);
+ if (!currentPackage) {
+ return [];
+ }
+
+ const { packageDependencies } = pnpApi.getPackageInformation(currentPackage);
+
+ const typeRoots: string[] = [];
+ for (const [name, referencish] of Array.from<any>(packageDependencies.entries())) {
+ // eslint-disable-next-line no-null/no-null
+ if (name.startsWith(`@types/`) && referencish !== null) {
+ const dependencyLocator = pnpApi.getLocator(name, referencish);
+ const { packageLocation } = pnpApi.getPackageInformation(dependencyLocator);
+
+ typeRoots.push(getDirectoryPath(packageLocation));
+ }
+ }
+
+ return typeRoots;
+}
+
+export function isImportablePathPnp(fromPath: string, toPath: string): boolean {
+ const pnpApi = getPnpApi(fromPath);
+
+ const fromLocator = pnpApi.findPackageLocator(fromPath);
+ const toLocator = pnpApi.findPackageLocator(toPath);
+
+ // eslint-disable-next-line no-null/no-null
+ if (toLocator === null) {
+ return false;
+ }
+
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ const toReference = fromInfo.packageDependencies.get(toLocator.name);
+
+ if (toReference) {
+ return toReference === toLocator.reference;
+ }
+
+ // Aliased dependencies
+ for (const reference of fromInfo.packageDependencies.values()) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+}

src/compiler/sys.ts

@@ -1728,6 +1728,10 @@ export let sys: System = (() => {
  }
 
  function isFileSystemCaseSensitive(): boolean {
+ // The PnP runtime is always case-sensitive
+ if (typeof process.versions.pnp !== `undefined`) {
+ return true;
+ }
  // win32\win64 are case insensitive platforms
  if (platform === "win32" || platform === "win64") {
  return false;

src/compiler/utilities.ts

@@ -10230,6 +10230,15 @@ export interface NodeModulePathParts {
  readonly packageRootIndex: number;
  readonly fileNameIndex: number;
 }
+
+/** @internal */
+export interface PackagePathParts {
+ readonly topLevelNodeModulesIndex: undefined;
+ readonly topLevelPackageNameIndex: undefined;
+ readonly packageRootIndex: number;
+ readonly fileNameIndex: number;
+}
+
 /** @internal */
 export function getNodeModulePathParts(fullPath: string): NodeModulePathParts | undefined {
  // If fullPath can't be valid module file within node_modules, returns undefined.

src/compiler/moduleNameResolver.ts

@@ -110,6 +110,10 @@ import {
  versionMajorMinor,
  VersionRange,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+ getPnpTypeRoots,
+} from "./pnp";
 
 /** @internal */
 export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void {
@@ -471,7 +475,7 @@ export function getEffectiveTypeRoots(options: CompilerOptions, host: GetEffecti
  * Returns the path to every node_modules/@types directory from some ancestor directory.
  * Returns undefined if there are none.
  */
-function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+function getNodeModulesTypeRoots(currentDirectory: string) {
  let typeRoots: string[] | undefined;
  forEachAncestorDirectory(normalizePath(currentDirectory), directory => {
  const atTypes = combinePaths(directory, nodeModulesAtTypes);
@@ -486,6 +490,18 @@ function arePathsEqual(path1: string, path2: string, host: ModuleResolutionHost)
  return comparePaths(path1, path2, !useCaseSensitiveFileNames) === Comparison.EqualTo;
 }
 
+function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+ const nmTypes = getNodeModulesTypeRoots(currentDirectory);
+ const pnpTypes = getPnpTypeRoots(currentDirectory);
+
+ if (nmTypes?.length) {
+ return [...nmTypes, ...pnpTypes];
+ }
+ else if (pnpTypes.length) {
+ return pnpTypes;
+ }
+}
+
 function getOriginalAndResolvedFileName(fileName: string, host: ModuleResolutionHost, traceEnabled: boolean) {
  const resolvedFileName = realPath(fileName, host, traceEnabled);
  const pathsAreEqual = arePathsEqual(fileName, resolvedFileName, host);
@@ -770,6 +786,18 @@ export function resolvePackageNameToPackageJson(
 ): PackageJsonInfo | undefined {
  const moduleResolutionState = getTemporaryModuleResolutionState(cache?.getPackageJsonInfoCache(), host, options);
 
+ const pnpapi = getPnpApi(containingDirectory);
+ if (pnpapi) {
+ try {
+ const resolution = pnpapi.resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ const candidate = normalizeSlashes(resolution).replace(/\/$/, "");
+ return getPackageJsonInfo(candidate, /*onlyRecordFailures*/ false, moduleResolutionState);
+ }
+ catch {
+ return;
+ }
+ }
+
  return forEachAncestorDirectory(containingDirectory, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const nodeModulesFolder = combinePaths(ancestorDirectory, "node_modules");
@@ -2938,7 +2966,16 @@ function loadModuleFromNearestNodeModulesDirectoryWorker(extensions: Extensions,
  }
 
  function lookup(extensions: Extensions) {
- return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
+ const issuer = normalizeSlashes(directory);
+ if (getPnpApi(issuer)) {
+ const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, issuer, redirectedReference, state);
+ if (resolutionFromCache) {
+ return resolutionFromCache;
+ }
+ return toSearchResult(loadModuleFromImmediateNodeModulesDirectoryPnP(extensions, moduleName, issuer, state, typesScopeOnly, cache, redirectedReference));
+ }
+
+ return forEachAncestorDirectory(issuer, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, ancestorDirectory, redirectedReference, state);
  if (resolutionFromCache) {
@@ -2977,11 +3014,34 @@ function loadModuleFromImmediateNodeModulesDirectory(extensions: Extensions, mod
  }
 }
 
+function loadModuleFromImmediateNodeModulesDirectoryPnP(extensions: Extensions, moduleName: string, directory: string, state: ModuleResolutionState, typesScopeOnly: boolean, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const issuer = normalizeSlashes(directory);
+
+ if (!typesScopeOnly) {
+ const packageResult = tryLoadModuleUsingPnpResolution(extensions, moduleName, issuer, state, cache, redirectedReference);
+ if (packageResult) {
+ return packageResult;
+ }
+ }
+
+ if (extensions & Extensions.Declaration) {
+ return tryLoadModuleUsingPnpResolution(Extensions.Declaration, `@types/${mangleScopedPackageNameWithTrace(moduleName, state)}`, issuer, state, cache, redirectedReference);
+ }
+}
+
 function loadModuleFromSpecificNodeModulesDirectory(extensions: Extensions, moduleName: string, nodeModulesDirectory: string, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
  const candidate = normalizePath(combinePaths(nodeModulesDirectory, moduleName));
  const { packageName, rest } = parsePackageName(moduleName);
  const packageDirectory = combinePaths(nodeModulesDirectory, packageName);
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, nodeModulesDirectoryExists, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
 
+function loadModuleFromPnpResolution(extensions: Extensions, packageDirectory: string, rest: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const candidate = normalizePath(combinePaths(packageDirectory, rest));
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, /*nodeModulesDirectoryExists*/ true, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
+
+function loadModuleFromSpecificNodeModulesDirectoryImpl(extensions: Extensions, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined, candidate: string, rest: string, packageDirectory: string): Resolved | undefined {
  let rootPackageInfo: PackageJsonInfo | undefined;
  // First look for a nested package.json, as in `node_modules/foo/bar/package.json`.
  let packageInfo = getPackageJsonInfo(candidate, !nodeModulesDirectoryExists, state);
@@ -3306,3 +3366,22 @@ function useCaseSensitiveFileNames(state: ModuleResolutionState) {
  typeof state.host.useCaseSensitiveFileNames === "boolean" ? state.host.useCaseSensitiveFileNames :
  state.host.useCaseSensitiveFileNames();
 }
+
+function loadPnpPackageResolution(packageName: string, containingDirectory: string) {
+ try {
+ const resolution = getPnpApi(containingDirectory).resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ return normalizeSlashes(resolution).replace(/\/$/, "");
+ }
+ catch {
+ // Nothing to do
+ }
+}
+
+function tryLoadModuleUsingPnpResolution(extensions: Extensions, moduleName: string, containingDirectory: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined) {
+ const { packageName, rest } = parsePackageName(moduleName);
+
+ const packageResolution = loadPnpPackageResolution(packageName, containingDirectory);
+ return packageResolution
+ ? loadModuleFromPnpResolution(extensions, packageResolution, rest, state, cache, redirectedReference)
+ : undefined;
+}

src/compiler/moduleSpecifiers.ts

@@ -84,6 +84,7 @@ import {
  NodeFlags,
  NodeModulePathParts,
  normalizePath,
+ PackagePathParts,
  Path,
  pathContainsNodeModules,
  pathIsBareSpecifier,
@@ -110,6 +111,9 @@ import {
  TypeChecker,
  UserPreferences,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+} from "./pnp";
 
 // Used by importFixes, getEditsForFileRename, and declaration emit to synthesize import module specifiers.
 
@@ -641,7 +645,17 @@ function getAllModulePathsWorker(importingFileName: Path, importedFileName: stri
  host,
  /*preferSymlinks*/ true,
  (path, isRedirect) => {
- const isInNodeModules = pathContainsNodeModules(path);
+ let isInNodeModules = pathContainsNodeModules(path);
+
+ const pnpapi = getPnpApi(path);
+ if (!isInNodeModules && pnpapi) {
+ const fromLocator = pnpapi.findPackageLocator(importingFileName);
+ const toLocator = pnpapi.findPackageLocator(path);
+ if (fromLocator && toLocator && fromLocator !== toLocator) {
+ isInNodeModules = true;
+ }
+ }
+
  allFileNames.set(path, { path: getCanonicalFileName(path), isRedirect, isInNodeModules });
  importedFileFromNodeModules = importedFileFromNodeModules || isInNodeModules;
  // don't return value, so we collect everything
@@ -907,7 +921,51 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  if (!host.fileExists || !host.readFile) {
  return undefined;
  }
- const parts: NodeModulePathParts = getNodeModulePathParts(path)!;
+ let parts: NodeModulePathParts | PackagePathParts | undefined = getNodeModulePathParts(path);
+
+ let pnpPackageName: string | undefined;
+
+ const pnpApi = getPnpApi(path);
+ if (pnpApi) {
+ const fromLocator = pnpApi.findPackageLocator(importingSourceFile.fileName);
+ const toLocator = pnpApi.findPackageLocator(path);
+
+ // Don't use the package name when the imported file is inside
+ // the source directory (prefer a relative path instead)
+ if (fromLocator === toLocator) {
+ return undefined;
+ }
+
+ if (fromLocator && toLocator) {
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ if (toLocator.reference === fromInfo.packageDependencies.get(toLocator.name)) {
+ pnpPackageName = toLocator.name;
+ }
+ else {
+ // Aliased dependencies
+ for (const [name, reference] of fromInfo.packageDependencies) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ pnpPackageName = name;
+ break;
+ }
+ }
+ }
+ }
+
+ if (!parts) {
+ const toInfo = pnpApi.getPackageInformation(toLocator);
+ parts = {
+ topLevelNodeModulesIndex: undefined,
+ topLevelPackageNameIndex: undefined,
+ // The last character from packageLocation is the trailing "/", we want to point to it
+ packageRootIndex: toInfo.packageLocation.length - 1,
+ fileNameIndex: path.lastIndexOf(`/`),
+ };
+ }
+ }
+ }
+
  if (!parts) {
  return undefined;
  }
@@ -952,19 +1010,26 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  return undefined;
  }
 
- const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
- // Get a path that's relative to node_modules or the importing file's path
- // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
- const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
- if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
- return undefined;
+ // If PnP is enabled the node_modules entries we'll get will always be relevant even if they
+ // are located in a weird path apparently outside of the source directory
+ if (typeof process.versions.pnp === "undefined") {
+ const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
+ // Get a path that's relative to node_modules or the importing file's path
+ // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
+ const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
+ if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
+ return undefined;
+ }
  }
 
  // If the module was found in @types, get the actual Node package name
- const nodeModulesDirectoryName = moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = typeof pnpPackageName !== "undefined"
+ ? pnpPackageName + moduleSpecifier.substring(parts.packageRootIndex)
+ : moduleSpecifier.substring(parts.topLevelPackageNameIndex! + 1);
+
+ const packageNameFromPath = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
  // For classic resolution, only allow importing from node_modules/@types, not other node_modules
- return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageName === nodeModulesDirectoryName ? undefined : packageName;
+ return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageNameFromPath === nodeModulesDirectoryName ? undefined : packageNameFromPath;
 
  function tryDirectoryWithPackageJson(packageRootIndex: number): { moduleFileToTry: string; packageRootPath?: string; blockedByExports?: true; verbatimFromExports?: true; } {
  const packageRootPath = path.substring(0, packageRootIndex);
@@ -979,8 +1044,8 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  // The package name that we found in node_modules could be different from the package
  // name in the package.json content via url/filepath dependency specifiers. We need to
  // use the actual directory name, so don't look at `packageJsonContent.name` here.
- const nodeModulesDirectoryName = packageRootPath.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = packageRootPath.substring(parts!.topLevelPackageNameIndex! + 1);
+ const packageName = getPackageNameFromTypesPackageName(pnpPackageName ? pnpPackageName : nodeModulesDirectoryName);
  const conditions = getConditions(options, importMode === ModuleKind.ESNext);
  const fromExports = packageJsonContent.exports
  ? tryGetModuleNameFromExports(options, path, packageRootPath, packageName, packageJsonContent.exports, conditions)
@@ -1046,7 +1111,7 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  }
  else {
  // No package.json exists; an index.js will still resolve as the package name
- const fileName = getCanonicalFileName(moduleFileToTry.substring(parts.packageRootIndex + 1));
+ const fileName = getCanonicalFileName(moduleFileToTry.substring(parts!.packageRootIndex + 1));
  if (fileName === "index.d.ts" || fileName === "index.js" || fileName === "index.ts" || fileName === "index.tsx") {
  return { moduleFileToTry, packageRootPath };
  }

src/compiler/pnp.ts

@@ -0,0 +1,80 @@
+import {
+ getDirectoryPath,
+ resolvePath,
+} from "./path";
+
+export function getPnpApi(path: string) {
+ if (typeof process.versions.pnp === "undefined") {
+ return;
+ }
+
+ const { findPnpApi } = require("module");
+ if (findPnpApi) {
+ return findPnpApi(`${path}/`);
+ }
+}
+
+export function getPnpApiPath(path: string): string | undefined {
+ // eslint-disable-next-line no-null/no-null
+ return getPnpApi(path)?.resolveRequest("pnpapi", /*issuer*/ null);
+}
+
+export function getPnpTypeRoots(currentDirectory: string) {
+ const pnpApi = getPnpApi(currentDirectory);
+ if (!pnpApi) {
+ return [];
+ }
+
+ // Some TS consumers pass relative paths that aren't normalized
+ currentDirectory = resolvePath(currentDirectory);
+
+ const currentPackage = pnpApi.findPackageLocator(`${currentDirectory}/`);
+ if (!currentPackage) {
+ return [];
+ }
+
+ const { packageDependencies } = pnpApi.getPackageInformation(currentPackage);
+
+ const typeRoots: string[] = [];
+ for (const [name, referencish] of Array.from<any>(packageDependencies.entries())) {
+ // eslint-disable-next-line no-null/no-null
+ if (name.startsWith(`@types/`) && referencish !== null) {
+ const dependencyLocator = pnpApi.getLocator(name, referencish);
+ const { packageLocation } = pnpApi.getPackageInformation(dependencyLocator);
+
+ typeRoots.push(getDirectoryPath(packageLocation));
+ }
+ }
+
+ return typeRoots;
+}
+
+export function isImportablePathPnp(fromPath: string, toPath: string): boolean {
+ const pnpApi = getPnpApi(fromPath);
+
+ const fromLocator = pnpApi.findPackageLocator(fromPath);
+ const toLocator = pnpApi.findPackageLocator(toPath);
+
+ // eslint-disable-next-line no-null/no-null
+ if (toLocator === null) {
+ return false;
+ }
+
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ const toReference = fromInfo.packageDependencies.get(toLocator.name);
+
+ if (toReference) {
+ return toReference === toLocator.reference;
+ }
+
+ // Aliased dependencies
+ for (const reference of fromInfo.packageDependencies.values()) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+}

src/compiler/sys.ts

@@ -1728,6 +1728,10 @@ export let sys: System = (() => {
  }
 
  function isFileSystemCaseSensitive(): boolean {
+ // The PnP runtime is always case-sensitive
+ if (typeof process.versions.pnp !== `undefined`) {
+ return true;
+ }
  // win32\win64 are case insensitive platforms
  if (platform === "win32" || platform === "win64") {
  return false;

src/compiler/utilities.ts

@@ -10230,6 +10230,15 @@ export interface NodeModulePathParts {
  readonly packageRootIndex: number;
  readonly fileNameIndex: number;
 }
+
+/** @internal */
+export interface PackagePathParts {
+ readonly topLevelNodeModulesIndex: undefined;
+ readonly topLevelPackageNameIndex: undefined;
+ readonly packageRootIndex: number;
+ readonly fileNameIndex: number;
+}
+
 /** @internal */
 export function getNodeModulePathParts(fullPath: string): NodeModulePathParts | undefined {
  // If fullPath can't be valid module file within node_modules, returns undefined.

src/compiler/moduleNameResolver.ts

@@ -110,6 +110,10 @@ import {
  versionMajorMinor,
  VersionRange,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+ getPnpTypeRoots,
+} from "./pnp";
 
 /** @internal */
 export function trace(host: ModuleResolutionHost, message: DiagnosticMessage, ...args: any[]): void {
@@ -471,7 +475,7 @@ export function getEffectiveTypeRoots(options: CompilerOptions, host: GetEffecti
  * Returns the path to every node_modules/@types directory from some ancestor directory.
  * Returns undefined if there are none.
  */
-function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+function getNodeModulesTypeRoots(currentDirectory: string) {
  let typeRoots: string[] | undefined;
  forEachAncestorDirectory(normalizePath(currentDirectory), directory => {
  const atTypes = combinePaths(directory, nodeModulesAtTypes);
@@ -486,6 +490,18 @@ function arePathsEqual(path1: string, path2: string, host: ModuleResolutionHost)
  return comparePaths(path1, path2, !useCaseSensitiveFileNames) === Comparison.EqualTo;
 }
 
+function getDefaultTypeRoots(currentDirectory: string): string[] | undefined {
+ const nmTypes = getNodeModulesTypeRoots(currentDirectory);
+ const pnpTypes = getPnpTypeRoots(currentDirectory);
+
+ if (nmTypes?.length) {
+ return [...nmTypes, ...pnpTypes];
+ }
+ else if (pnpTypes.length) {
+ return pnpTypes;
+ }
+}
+
 function getOriginalAndResolvedFileName(fileName: string, host: ModuleResolutionHost, traceEnabled: boolean) {
  const resolvedFileName = realPath(fileName, host, traceEnabled);
  const pathsAreEqual = arePathsEqual(fileName, resolvedFileName, host);
@@ -770,6 +786,18 @@ export function resolvePackageNameToPackageJson(
 ): PackageJsonInfo | undefined {
  const moduleResolutionState = getTemporaryModuleResolutionState(cache?.getPackageJsonInfoCache(), host, options);
 
+ const pnpapi = getPnpApi(containingDirectory);
+ if (pnpapi) {
+ try {
+ const resolution = pnpapi.resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ const candidate = normalizeSlashes(resolution).replace(/\/$/, "");
+ return getPackageJsonInfo(candidate, /*onlyRecordFailures*/ false, moduleResolutionState);
+ }
+ catch {
+ return;
+ }
+ }
+
  return forEachAncestorDirectory(containingDirectory, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const nodeModulesFolder = combinePaths(ancestorDirectory, "node_modules");
@@ -2938,7 +2966,16 @@ function loadModuleFromNearestNodeModulesDirectoryWorker(extensions: Extensions,
  }
 
  function lookup(extensions: Extensions) {
- return forEachAncestorDirectory(normalizeSlashes(directory), ancestorDirectory => {
+ const issuer = normalizeSlashes(directory);
+ if (getPnpApi(issuer)) {
+ const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, issuer, redirectedReference, state);
+ if (resolutionFromCache) {
+ return resolutionFromCache;
+ }
+ return toSearchResult(loadModuleFromImmediateNodeModulesDirectoryPnP(extensions, moduleName, issuer, state, typesScopeOnly, cache, redirectedReference));
+ }
+
+ return forEachAncestorDirectory(issuer, ancestorDirectory => {
  if (getBaseFileName(ancestorDirectory) !== "node_modules") {
  const resolutionFromCache = tryFindNonRelativeModuleNameInCache(cache, moduleName, mode, ancestorDirectory, redirectedReference, state);
  if (resolutionFromCache) {
@@ -2977,11 +3014,34 @@ function loadModuleFromImmediateNodeModulesDirectory(extensions: Extensions, mod
  }
 }
 
+function loadModuleFromImmediateNodeModulesDirectoryPnP(extensions: Extensions, moduleName: string, directory: string, state: ModuleResolutionState, typesScopeOnly: boolean, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const issuer = normalizeSlashes(directory);
+
+ if (!typesScopeOnly) {
+ const packageResult = tryLoadModuleUsingPnpResolution(extensions, moduleName, issuer, state, cache, redirectedReference);
+ if (packageResult) {
+ return packageResult;
+ }
+ }
+
+ if (extensions & Extensions.Declaration) {
+ return tryLoadModuleUsingPnpResolution(Extensions.Declaration, `@types/${mangleScopedPackageNameWithTrace(moduleName, state)}`, issuer, state, cache, redirectedReference);
+ }
+}
+
 function loadModuleFromSpecificNodeModulesDirectory(extensions: Extensions, moduleName: string, nodeModulesDirectory: string, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
  const candidate = normalizePath(combinePaths(nodeModulesDirectory, moduleName));
  const { packageName, rest } = parsePackageName(moduleName);
  const packageDirectory = combinePaths(nodeModulesDirectory, packageName);
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, nodeModulesDirectoryExists, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
 
+function loadModuleFromPnpResolution(extensions: Extensions, packageDirectory: string, rest: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined): Resolved | undefined {
+ const candidate = normalizePath(combinePaths(packageDirectory, rest));
+ return loadModuleFromSpecificNodeModulesDirectoryImpl(extensions, /*nodeModulesDirectoryExists*/ true, state, cache, redirectedReference, candidate, rest, packageDirectory);
+}
+
+function loadModuleFromSpecificNodeModulesDirectoryImpl(extensions: Extensions, nodeModulesDirectoryExists: boolean, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined, candidate: string, rest: string, packageDirectory: string): Resolved | undefined {
  let rootPackageInfo: PackageJsonInfo | undefined;
  // First look for a nested package.json, as in `node_modules/foo/bar/package.json`.
  let packageInfo = getPackageJsonInfo(candidate, !nodeModulesDirectoryExists, state);
@@ -3306,3 +3366,22 @@ function useCaseSensitiveFileNames(state: ModuleResolutionState) {
  typeof state.host.useCaseSensitiveFileNames === "boolean" ? state.host.useCaseSensitiveFileNames :
  state.host.useCaseSensitiveFileNames();
 }
+
+function loadPnpPackageResolution(packageName: string, containingDirectory: string) {
+ try {
+ const resolution = getPnpApi(containingDirectory).resolveToUnqualified(packageName, `${containingDirectory}/`, { considerBuiltins: false });
+ return normalizeSlashes(resolution).replace(/\/$/, "");
+ }
+ catch {
+ // Nothing to do
+ }
+}
+
+function tryLoadModuleUsingPnpResolution(extensions: Extensions, moduleName: string, containingDirectory: string, state: ModuleResolutionState, cache: ModuleResolutionCache | undefined, redirectedReference: ResolvedProjectReference | undefined) {
+ const { packageName, rest } = parsePackageName(moduleName);
+
+ const packageResolution = loadPnpPackageResolution(packageName, containingDirectory);
+ return packageResolution
+ ? loadModuleFromPnpResolution(extensions, packageResolution, rest, state, cache, redirectedReference)
+ : undefined;
+}

src/compiler/moduleSpecifiers.ts

@@ -84,6 +84,7 @@ import {
  NodeFlags,
  NodeModulePathParts,
  normalizePath,
+ PackagePathParts,
  Path,
  pathContainsNodeModules,
  pathIsBareSpecifier,
@@ -110,6 +111,9 @@ import {
  TypeChecker,
  UserPreferences,
 } from "./_namespaces/ts";
+import {
+ getPnpApi,
+} from "./pnp";
 
 // Used by importFixes, getEditsForFileRename, and declaration emit to synthesize import module specifiers.
 
@@ -641,7 +645,17 @@ function getAllModulePathsWorker(importingFileName: Path, importedFileName: stri
  host,
  /*preferSymlinks*/ true,
  (path, isRedirect) => {
- const isInNodeModules = pathContainsNodeModules(path);
+ let isInNodeModules = pathContainsNodeModules(path);
+
+ const pnpapi = getPnpApi(path);
+ if (!isInNodeModules && pnpapi) {
+ const fromLocator = pnpapi.findPackageLocator(importingFileName);
+ const toLocator = pnpapi.findPackageLocator(path);
+ if (fromLocator && toLocator && fromLocator !== toLocator) {
+ isInNodeModules = true;
+ }
+ }
+
  allFileNames.set(path, { path: getCanonicalFileName(path), isRedirect, isInNodeModules });
  importedFileFromNodeModules = importedFileFromNodeModules || isInNodeModules;
  // don't return value, so we collect everything
@@ -907,7 +921,51 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  if (!host.fileExists || !host.readFile) {
  return undefined;
  }
- const parts: NodeModulePathParts = getNodeModulePathParts(path)!;
+ let parts: NodeModulePathParts | PackagePathParts | undefined = getNodeModulePathParts(path);
+
+ let pnpPackageName: string | undefined;
+
+ const pnpApi = getPnpApi(path);
+ if (pnpApi) {
+ const fromLocator = pnpApi.findPackageLocator(importingSourceFile.fileName);
+ const toLocator = pnpApi.findPackageLocator(path);
+
+ // Don't use the package name when the imported file is inside
+ // the source directory (prefer a relative path instead)
+ if (fromLocator === toLocator) {
+ return undefined;
+ }
+
+ if (fromLocator && toLocator) {
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ if (toLocator.reference === fromInfo.packageDependencies.get(toLocator.name)) {
+ pnpPackageName = toLocator.name;
+ }
+ else {
+ // Aliased dependencies
+ for (const [name, reference] of fromInfo.packageDependencies) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ pnpPackageName = name;
+ break;
+ }
+ }
+ }
+ }
+
+ if (!parts) {
+ const toInfo = pnpApi.getPackageInformation(toLocator);
+ parts = {
+ topLevelNodeModulesIndex: undefined,
+ topLevelPackageNameIndex: undefined,
+ // The last character from packageLocation is the trailing "/", we want to point to it
+ packageRootIndex: toInfo.packageLocation.length - 1,
+ fileNameIndex: path.lastIndexOf(`/`),
+ };
+ }
+ }
+ }
+
  if (!parts) {
  return undefined;
  }
@@ -952,19 +1010,26 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  return undefined;
  }
 
- const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
- // Get a path that's relative to node_modules or the importing file's path
- // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
- const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
- if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
- return undefined;
+ // If PnP is enabled the node_modules entries we'll get will always be relevant even if they
+ // are located in a weird path apparently outside of the source directory
+ if (typeof process.versions.pnp === "undefined") {
+ const globalTypingsCacheLocation = host.getGlobalTypingsCacheLocation && host.getGlobalTypingsCacheLocation();
+ // Get a path that's relative to node_modules or the importing file's path
+ // if node_modules folder is in this folder or any of its parent folders, no need to keep it.
+ const pathToTopLevelNodeModules = getCanonicalFileName(moduleSpecifier.substring(0, parts.topLevelNodeModulesIndex));
+ if (!(startsWith(sourceDirectory, pathToTopLevelNodeModules) || globalTypingsCacheLocation && startsWith(getCanonicalFileName(globalTypingsCacheLocation), pathToTopLevelNodeModules))) {
+ return undefined;
+ }
  }
 
  // If the module was found in @types, get the actual Node package name
- const nodeModulesDirectoryName = moduleSpecifier.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = typeof pnpPackageName !== "undefined"
+ ? pnpPackageName + moduleSpecifier.substring(parts.packageRootIndex)
+ : moduleSpecifier.substring(parts.topLevelPackageNameIndex! + 1);
+
+ const packageNameFromPath = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
  // For classic resolution, only allow importing from node_modules/@types, not other node_modules
- return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageName === nodeModulesDirectoryName ? undefined : packageName;
+ return getEmitModuleResolutionKind(options) === ModuleResolutionKind.Classic && packageNameFromPath === nodeModulesDirectoryName ? undefined : packageNameFromPath;
 
  function tryDirectoryWithPackageJson(packageRootIndex: number): { moduleFileToTry: string; packageRootPath?: string; blockedByExports?: true; verbatimFromExports?: true; } {
  const packageRootPath = path.substring(0, packageRootIndex);
@@ -979,8 +1044,8 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  // The package name that we found in node_modules could be different from the package
  // name in the package.json content via url/filepath dependency specifiers. We need to
  // use the actual directory name, so don't look at `packageJsonContent.name` here.
- const nodeModulesDirectoryName = packageRootPath.substring(parts.topLevelPackageNameIndex + 1);
- const packageName = getPackageNameFromTypesPackageName(nodeModulesDirectoryName);
+ const nodeModulesDirectoryName = packageRootPath.substring(parts!.topLevelPackageNameIndex! + 1);
+ const packageName = getPackageNameFromTypesPackageName(pnpPackageName ? pnpPackageName : nodeModulesDirectoryName);
  const conditions = getConditions(options, importMode === ModuleKind.ESNext);
  const fromExports = packageJsonContent.exports
  ? tryGetModuleNameFromExports(options, path, packageRootPath, packageName, packageJsonContent.exports, conditions)
@@ -1046,7 +1111,7 @@ function tryGetModuleNameAsNodeModule({ path, isRedirect }: ModulePath, { getCan
  }
  else {
  // No package.json exists; an index.js will still resolve as the package name
- const fileName = getCanonicalFileName(moduleFileToTry.substring(parts.packageRootIndex + 1));
+ const fileName = getCanonicalFileName(moduleFileToTry.substring(parts!.packageRootIndex + 1));
  if (fileName === "index.d.ts" || fileName === "index.js" || fileName === "index.ts" || fileName === "index.tsx") {
  return { moduleFileToTry, packageRootPath };
  }

src/compiler/pnp.ts

@@ -0,0 +1,80 @@
+import {
+ getDirectoryPath,
+ resolvePath,
+} from "./path";
+
+export function getPnpApi(path: string) {
+ if (typeof process.versions.pnp === "undefined") {
+ return;
+ }
+
+ const { findPnpApi } = require("module");
+ if (findPnpApi) {
+ return findPnpApi(`${path}/`);
+ }
+}
+
+export function getPnpApiPath(path: string): string | undefined {
+ // eslint-disable-next-line no-null/no-null
+ return getPnpApi(path)?.resolveRequest("pnpapi", /*issuer*/ null);
+}
+
+export function getPnpTypeRoots(currentDirectory: string) {
+ const pnpApi = getPnpApi(currentDirectory);
+ if (!pnpApi) {
+ return [];
+ }
+
+ // Some TS consumers pass relative paths that aren't normalized
+ currentDirectory = resolvePath(currentDirectory);
+
+ const currentPackage = pnpApi.findPackageLocator(`${currentDirectory}/`);
+ if (!currentPackage) {
+ return [];
+ }
+
+ const { packageDependencies } = pnpApi.getPackageInformation(currentPackage);
+
+ const typeRoots: string[] = [];
+ for (const [name, referencish] of Array.from<any>(packageDependencies.entries())) {
+ // eslint-disable-next-line no-null/no-null
+ if (name.startsWith(`@types/`) && referencish !== null) {
+ const dependencyLocator = pnpApi.getLocator(name, referencish);
+ const { packageLocation } = pnpApi.getPackageInformation(dependencyLocator);
+
+ typeRoots.push(getDirectoryPath(packageLocation));
+ }
+ }
+
+ return typeRoots;
+}
+
+export function isImportablePathPnp(fromPath: string, toPath: string): boolean {
+ const pnpApi = getPnpApi(fromPath);
+
+ const fromLocator = pnpApi.findPackageLocator(fromPath);
+ const toLocator = pnpApi.findPackageLocator(toPath);
+
+ // eslint-disable-next-line no-null/no-null
+ if (toLocator === null) {
+ return false;
+ }
+
+ const fromInfo = pnpApi.getPackageInformation(fromLocator);
+ const toReference = fromInfo.packageDependencies.get(toLocator.name);
+
+ if (toReference) {
+ return toReference === toLocator.reference;
+ }
+
+ // Aliased dependencies
+ for (const reference of fromInfo.packageDependencies.values()) {
+ if (Array.isArray(reference)) {
+ if (reference[0] === toLocator.name && reference[1] === toLocator.reference) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+}

src/compiler/sys.ts

@@ -1728,6 +1728,10 @@ export let sys: System = (() => {
  }
 
  function isFileSystemCaseSensitive(): boolean {
+ // The PnP runtime is always case-sensitive
+ if (typeof process.versions.pnp !== `undefined`) {
+ return true;
+ }
  // win32\win64 are case insensitive platforms
  if (platform === "win32" || platform === "win64") {
  return false;

src/compiler/utilities.ts

@@ -10230,6 +10230,15 @@ export interface NodeModulePathParts {
  readonly packageRootIndex: number;
  readonly fileNameIndex: number;
 }
+
+/** @internal */
+export interface PackagePathParts {
+ readonly topLevelNodeModulesIndex: undefined;
+ readonly topLevelPackageNameIndex: undefined;
+ readonly packageRootIndex: number;
+ readonly fileNameIndex: number;
+}
+
 /** @internal */
 export function getNodeModulePathParts(fullPath: string): NodeModulePathParts | undefined {
  // If fullPath can't be valid module file within node_modules, returns undefined.