esm: better error message for unsupported URL

The default ESM loader supports only file and data URLs.
This PR adds better error message for it.
PR-URL: #31129
Reviewed-By: Gus Caplan <me@gus.host>
Reviewed-By: Guy Bedford <guybedford@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>

Author: Hakerh400

doc/api/errors.md

@@ -1957,6 +1957,11 @@ An attempt was made to load a module with an unknown or unsupported format.
 An invalid or unknown process signal was passed to an API expecting a valid
 signal (such as [`subprocess.kill()`][]).
 
+<aid="ERR_UNSUPPORTED_ESM_URL_SCHEME"></a>
+### `ERR_UNSUPPORTED_ESM_URL_SCHEME`
+
+`import` with URL schemes other than `file` and `data` is unsupported.
+
 <aid="ERR_V8BREAKITERATOR"></a>
 ### `ERR_V8BREAKITERATOR`
 

lib/internal/errors.js

@@ -1335,6 +1335,8 @@ E('ERR_UNKNOWN_FILE_EXTENSION',
 TypeError);
 E('ERR_UNKNOWN_MODULE_FORMAT','Unknown module format: %s',RangeError);
 E('ERR_UNKNOWN_SIGNAL','Unknown signal: %s',TypeError);
+E('ERR_UNSUPPORTED_ESM_URL_SCHEME','Only file and data URLs are supported '+
+'by the default ESM loader',Error);
 
 E('ERR_V8BREAKITERATOR',
 'Full ICU data not installed. See https://github.com/nodejs/node/wiki/Intl',

lib/internal/modules/esm/default_resolve.js

@@ -21,7 +21,8 @@ const { resolve: moduleWrapResolve,
  getPackageType }=internalBinding('module_wrap');
 const{URL, pathToFileURL, fileURLToPath }=require('internal/url');
 const{ERR_INPUT_TYPE_NOT_ALLOWED,
-ERR_UNKNOWN_FILE_EXTENSION}=require('internal/errors').codes;
+ERR_UNKNOWN_FILE_EXTENSION,
+ERR_UNSUPPORTED_ESM_URL_SCHEME}=require('internal/errors').codes;
 
 constrealpathCache=newSafeMap();
 
@@ -52,8 +53,9 @@ if (experimentalJsonModules)
 extensionFormatMap['.json']=legacyExtensionFormatMap['.json']='json';
 
 functionresolve(specifier,parentURL){
+letparsed;
 try{
-constparsed=newURL(specifier);
+parsed=newURL(specifier);
 if(parsed.protocol==='data:'){
 const[,mime]=/^([^/]+\/[^;,]+)(?:[^,]*?)(;base64)?,/.exec(parsed.pathname)||[null,null,null];
 constformat=({
@@ -68,6 +70,8 @@ function resolve(specifier, parentURL) {
 };
 }
 }catch{}
+if(parsed&&parsed.protocol!=='file:'&&parsed.protocol!=='data:')
+thrownewERR_UNSUPPORTED_ESM_URL_SCHEME();
 if(NativeModule.canBeRequiredByUsers(specifier)){
 return{
 url: specifier,

test/es-module/test-esm-dynamic-import.js

@@ -15,8 +15,8 @@ function expectErrorProperty(result, propertyKey, value) {
 }));
 }
 
-functionexpectMissingModuleError(result){
-expectErrorProperty(result,'code','ERR_MODULE_NOT_FOUND');
+functionexpectModuleError(result,err){
+expectErrorProperty(result,'code',err);
 }
 
 functionexpectOkNamespace(result){
@@ -56,10 +56,10 @@ function expectFsNamespace(result) {
 expectFsNamespace(eval('import("fs")'));
 expectFsNamespace(eval('import("fs")'));
 
-expectMissingModuleError(import('./not-an-existing-module.mjs'));
-// TODO(jkrems): Right now this doesn't hit a protocol error because the
-// module resolution step already rejects it. These arguably should be
-// protocol errors.
-expectMissingModuleError(import('node:fs'));
-expectMissingModuleError(import('http://example.com/foo.js'));
+expectModuleError(import('./not-an-existing-module.mjs'),
+'ERR_MODULE_NOT_FOUND');
+expectModuleError(import('node:fs'),
+'ERR_UNSUPPORTED_ESM_URL_SCHEME');
+expectModuleError(import('http://example.com/foo.js'),
+'ERR_UNSUPPORTED_ESM_URL_SCHEME');
 })();