module: deprecate trailing slash pattern mappings

PR-URL: #40039
Reviewed-By: Antoine du Hamel <duhamelantoine1995@gmail.com>
Reviewed-By: Geoffrey Booth <webmaster@geoffreybooth.com>

Author: guybedford

doc/api/deprecations.md

@@ -2812,6 +2812,20 @@ Type: Documentation-only (supports [`--pending-deprecation`][])
 The `'hash'` and `'mgf1Hash'` options are replaced with `'hashAlgorithm'`
 and `'mgf1HashAlgorithm'`.
 
+### DEP0155: Trailing slashes in pattern specifier resolutions
+<!-- YAML
+changes:
+ - version: REPLACEME
+ pr-url: https://github.com/nodejs/node/pull/40039
+ description: Documentation-only deprecation
+ with `--pending-deprecation` support.
+-->
+
+Type: Documentation-only (supports [`--pending-deprecation`][])
+
+The remapping of specifiers ending in `"/"` like `import 'pkg/x/'` is deprecated
+for package `"exports"` and `"imports"` pattern resolutions.
+
 [Legacy URL API]: url.md#url_legacy_url_api
 [NIST SP 800-38D]: https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf
 [RFC 6066]: https://tools.ietf.org/html/rfc6066#section-3

doc/api/esm.md

@@ -1190,6 +1190,8 @@ _isImports_, _conditions_)
 > _expansionKey_ up to but excluding the first _"*"_ character.
 > 1. If _patternBase_ is not **null** and _matchKey_ starts with but is not
 > equal to _patternBase_, then
+> 1. If _matchKey_ ends with _"/"_, throw an _Invalid Module Specifier_
+> error.
 > 1. Let _patternTrailer_ be the substring of _expansionKey_ from the
 > index after the first _"*"_ character.
 > 1. If _patternTrailer_ has zero length, or if _matchKey_ ends with

lib/internal/modules/esm/resolve.js

@@ -40,6 +40,7 @@ const { sep, relative, resolve } = require('path');
 constpreserveSymlinks=getOptionValue('--preserve-symlinks');
 constpreserveSymlinksMain=getOptionValue('--preserve-symlinks-main');
 consttypeFlag=getOptionValue('--input-type');
+constpendingDeprecation=getOptionValue('--pending-deprecation');
 const{URL, pathToFileURL, fileURLToPath }=require('internal/url');
 const{
 ERR_INPUT_TYPE_NOT_ALLOWED,
@@ -106,6 +107,22 @@ function emitFolderMapDeprecation(match, pjsonUrl, isExports, base) {
 );
 }
 
+functionemitTrailingSlashPatternDeprecation(match,pjsonUrl,isExports,base){
+if(!pendingDeprecation)return;
+constpjsonPath=fileURLToPath(pjsonUrl);
+if(emittedPackageWarnings.has(pjsonPath+'|'+match))
+return;
+emittedPackageWarnings.add(pjsonPath+'|'+match);
+process.emitWarning(
+`Use of deprecated trailing slash pattern mapping "${match}" in the ${
+isExports ? '"exports"' : '"imports"'} field module resolution of the `+
+`package at ${pjsonPath}${base ? ` imported from ${fileURLToPath(base)}` :
+''}. Mapping specifiers ending in "/" is no longer supported.`,
+'DeprecationWarning',
+'DEP0155'
+);
+}
+
 /**
  * @param {URL} url
  * @param {URL} packageJSONUrl
@@ -639,6 +656,9 @@ function packageExportsResolve(
 if(patternIndex!==-1&&
 StringPrototypeStartsWith(packageSubpath,
 StringPrototypeSlice(key,0,patternIndex))){
+if(StringPrototypeEndsWith(packageSubpath,'/'))
+emitTrailingSlashPatternDeprecation(packageSubpath,packageJSONUrl,
+true,base);
 constpatternTrailer=StringPrototypeSlice(key,patternIndex+1);
 if(packageSubpath.length>=key.length&&
 StringPrototypeEndsWith(packageSubpath,patternTrailer)&&

test/es-module/test-esm-exports-deprecations.mjs

@@ -1,11 +1,15 @@
+// Flags: --pending-deprecation
 import{mustCall}from'../common/index.mjs';
 importassertfrom'assert';
 
 letcurWarning=0;
 constexpectedWarnings=[
 '"./sub/"',
 '"./fallbackdir/"',
+'"./trailing-pattern-slash/"',
 '"./subpath/"',
+'"./subpath/dir1/"',
+'"./subpath/dir2/"',
 'no_exports',
 'default_index',
 ];

test/es-module/test-esm-exports.mjs

@@ -41,13 +41,19 @@ import fromInside from '../fixtures/node_modules/pkgexports/lib/hole.js';
 ['pkgexports/dir2/dir2/trailer',{default: 'index'}],
 ['pkgexports/a/dir1/dir1',{default: 'main'}],
 ['pkgexports/a/b/dir1/dir1',{default: 'main'}],
+
+// Deprecated:
+['pkgexports/trailing-pattern-slash/',
+{default: 'trailing-pattern-slash'}],
 ]);
 
 if(isRequire){
 validSpecifiers.set('pkgexports/subpath/file',{default: 'file'});
 validSpecifiers.set('pkgexports/subpath/dir1',{default: 'main'});
+// Deprecated:
 validSpecifiers.set('pkgexports/subpath/dir1/',{default: 'main'});
 validSpecifiers.set('pkgexports/subpath/dir2',{default: 'index'});
+// Deprecated:
 validSpecifiers.set('pkgexports/subpath/dir2/',{default: 'index'});
 }else{
 // No exports or main field

test/es-module/test-esm-local-deprecations.mjs

@@ -1,3 +1,5 @@
+// Flags: --pending-deprecation
+
 import'../common/index.mjs';
 importassertfrom'assert';
 importfixturesfrom'../common/fixtures.js';
@@ -9,10 +11,14 @@ const selfDeprecatedFolders =
 constdeprecatedFoldersIgnore=
 fixtures.path('/es-modules/deprecated-folders-ignore/main.js');
 
+constdeprecatedTrailingSlashPattern=
+fixtures.path('/es-modules/pattern-trailing-slash.mjs');
+
 constexpectedWarnings=[
 '"./" in the "exports" field',
 '"#self/" in the "imports" field',
 '"./folder/" in the "exports" field',
+'"./trailing-pattern-slash/" in the "exports" field',
 ];
 
 process.addListener('warning',(warning)=>{
@@ -28,5 +34,6 @@ process.on('exit', () => {
 (async()=>{
 awaitimport(pathToFileURL(selfDeprecatedFolders));
 awaitimport(pathToFileURL(deprecatedFoldersIgnore));
+awaitimport(pathToFileURL(deprecatedTrailingSlashPattern));
 })()
 .catch((err)=>console.error(err));

test/fixtures/es-modules/pattern-trailing-slash.mjs

@@ -0,0 +1 @@
+import'pkgexports/trailing-pattern-slash/';