src: remove experimental ShadowRealm support

The TC39 ShadowRealm proposal remains unimplemented by browsers,
and WPT removed ShadowRealm test coverage. Remove the Node.js
host integration, the --experimental-shadow-realm CLI flag, and
related tests.

Refs: web-platform-tests/wpt#59794
Refs: #42528
Signed-off-by: Yagiz Nizipli <yagiz@nizipli.com>
Co-authored-by: Yagiz Nizipli <anonrig@users.noreply.github.com>

Author: anonrig

doc/api/cli.md

@@ -1419,16 +1419,6 @@ Use this flag to generate a blob that can be injected into the Node.js
 binary to produce a [single executable application][]. See the documentation
 about [this configuration][`--experimental-sea-config`] for details.
 
-### `--experimental-shadow-realm`
-
-<!-- YAML
-added:
-  - v19.0.0
-  - v18.13.0
--->
-
-Use this flag to enable [ShadowRealm][] support.
-
 ### `--experimental-storage-inspection`
 
 <!-- YAML
@@ -3914,7 +3904,6 @@ one is included in the list below.
 * `--experimental-quic`
 * `--experimental-repl-await`
 * `--experimental-require-module`
-* `--experimental-shadow-realm`
 * `--experimental-specifier-resolution`
 * `--experimental-stream-iter`
 * `--experimental-test-isolation`
@@ -4419,8 +4408,6 @@ documented here:
 
 ### `--expose-gc`
 
-### `--harmony-shadow-realm`
-
 ### `--heap-snapshot-on-oom`
 
 ### `--interpreted-frames-native-stack`
@@ -4526,7 +4513,6 @@ node --stack-trace-limit=12 -p -e "Error.stackTraceLimit" # prints 12
 [Permission Model]: permissions.md#permission-model
 [REPL]: repl.md
 [ScriptCoverage]: https://chromedevtools.github.io/devtools-protocol/tot/Profiler#type-ScriptCoverage
-[ShadowRealm]: https://github.com/tc39/proposal-shadowrealm
 [Source Map]: https://tc39.es/ecma426/
 [Test tags]: test.md#test-tags
 [TypeScript type-stripping]: typescript.md#type-stripping

doc/node-config-schema.json

@@ -252,10 +252,6 @@
               "type": "boolean",
               "description": "Legacy alias for --require-module"
             },
-            "experimental-shadow-realm": {
-              "type": "boolean",
-              "description": ""
-            },
             "experimental-sqlite": {
               "type": "boolean",
               "description": "experimental node:sqlite module"

doc/node.1

@@ -791,9 +791,6 @@ Use this flag to generate a blob that can be injected into the Node.js
 binary to produce a single executable application. See the documentation
 about this configuration for details.
 .
-.It Fl -experimental-shadow-realm
-Use this flag to enable ShadowRealm support.
-.
 .It Fl -experimental-storage-inspection
 Enable experimental support for storage inspection
 .
@@ -2016,8 +2013,6 @@ one is included in the list below.
 .It
 \fB--experimental-require-module\fR
 .It
-\fB--experimental-shadow-realm\fR
-.It
 \fB--experimental-specifier-resolution\fR
 .It
 \fB--experimental-stream-iter\fR

eslint.config.mjs

@@ -143,7 +143,6 @@ export default [
         ReadableStreamDefaultReader: 'readonly',
         Response: 'readonly',
         sessionStorage: 'readonly',
-        ShadowRealm: 'readonly',
         Storage: 'readonly',
         SubtleCrypto: 'readonly',
         TextDecoderStream: 'readonly',

lib/eslint.config_partial.mjs

@@ -240,12 +240,6 @@ export default [
           name: 'Response',
           message: "Use `const { Response } = require('internal/deps/undici/undici');` instead of the global.",
         },
-        // ShadowRealm is not available in primordials because it can be
-        // disabled with --no-harmony-shadow-realm CLI flag.
-        {
-          name: 'ShadowRealm',
-          message: 'Use `const { ShadowRealm } = globalThis;` instead of the global.',
-        },
         // SharedArrayBuffer is not available in primordials because it can be
         // disabled with --enable-sharedarraybuffer-per-context CLI flag.
         {

lib/internal/bootstrap/realm.js

@@ -1,5 +1,5 @@
 // This file is executed in every realm that is created by Node.js, including
-// the context of main thread, worker threads, and ShadowRealms.
+// the context of the main thread and worker threads.
 // Only per-realm internal states and bindings should be bootstrapped in this
 // file and no globals should be exposed to the user code.
 //
@@ -226,8 +226,8 @@ const internalBuiltinIds = builtinIds
   .filter((id) => StringPrototypeStartsWith(id, 'internal/') && id !== selfId);
 
 // When --expose-internals is on we'll add the internal builtin ids to these.
-let canBeRequiredByUsersList = new SafeSet(publicBuiltinIds);
-let canBeRequiredByUsersWithoutSchemeList =
+const canBeRequiredByUsersList = new SafeSet(publicBuiltinIds);
+const canBeRequiredByUsersWithoutSchemeList =
   new SafeSet(publicBuiltinIds.filter((id) => !schemelessBlockList.has(id)));
 
 /**
@@ -280,13 +280,6 @@ class BuiltinModule {
     }
   }
 
-  static setRealmAllowRequireByUsers(ids) {
-    canBeRequiredByUsersList =
-      new SafeSet(ArrayPrototypeFilter(ids, (id) => ArrayPrototypeIncludes(publicBuiltinIds, id)));
-    canBeRequiredByUsersWithoutSchemeList =
-      new SafeSet(ArrayPrototypeFilter(ids, (id) => !schemelessBlockList.has(id)));
-  }
-
   // To be called during pre-execution when --expose-internals is on.
   // Enables the user-land module loader to access internal modules.
   static exposeInternals() {

lib/internal/bootstrap/shadow_realm.js

@@ -121,11 +121,9 @@ function isPermissionModelError(err) {
 
 /**
  * Every realm has its own prepareStackTraceCallback. When `error.stack` is
- * accessed, if the error is created in a shadow realm, the shadow realm's
- * prepareStackTraceCallback is invoked. Otherwise, the principal realm's
- * prepareStackTraceCallback is invoked. Note that accessing `error.stack`
- * of error objects created in a VM Context will always invoke the
- * prepareStackTraceCallback of the principal realm.
+ * accessed, the principal realm's prepareStackTraceCallback is invoked.
+ * Note that accessing `error.stack` of error objects created in a VM Context
+ * will always invoke the prepareStackTraceCallback of the principal realm.
  * @param {object} globalThis The global object of the realm that the error was
  *   created in. When the error object is created in a VM Context, this is the
  *   global object of that VM Context.

lib/internal/errors.js

@@ -74,34 +74,6 @@ function prepareWorkerThreadExecution() {
   });
 }
 
-function prepareShadowRealmExecution() {
-  // Patch the process object with legacy properties and normalizations.
-  // Do not expand argv1 as it is not available in ShadowRealm.
-  patchProcessObject(false);
-  setupDebugEnv();
-
-  // Disable custom loaders in ShadowRealm.
-  initializeModuleLoaders({ shouldSpawnLoaderHookWorker: false, shouldPreloadModules: false });
-  const {
-    privateSymbols: {
-      host_defined_option_symbol,
-    },
-  } = internalBinding('util');
-  const {
-    vm_dynamic_import_default_internal,
-  } = internalBinding('symbols');
-
-  // For ShadowRealm.prototype.importValue(), the referrer name is
-  // always null, so the native ImportModuleDynamically() callback would
-  // always fallback to look up the host-defined option from the
-  // global object using host_defined_option_symbol. Using
-  // vm_dynamic_import_default_internal as the host-defined option
-  // instructs the JS-land importModuleDynamicallyCallback() to
-  // proxy the request to defaultImportModuleDynamically().
-  globalThis[host_defined_option_symbol] =
-    vm_dynamic_import_default_internal;
-}
-
 function prepareExecution(options) {
   const { expandArgv1, initializeModules, isMainThread, shouldSpawnLoaderHookWorker, shouldPreloadModules } = options;
 
@@ -247,7 +219,6 @@ function initializeModuleLoaders(options) {
   }
   // Do not enable preload modules if custom loaders are disabled.
   // For example, loader workers are responsible for doing this themselves.
-  // And preload modules are not supported in ShadowRealm as well.
   if (shouldPreloadModules) {
     loadPreloadModules();
   }
@@ -830,7 +801,6 @@ module.exports = {
   initializeModuleLoaders,
   prepareMainThreadExecution,
   prepareWorkerThreadExecution,
-  prepareShadowRealmExecution,
   prepareTestRunnerMainExecution,
   markBootstrapComplete,
   loadPreloadModules,

lib/internal/process/pre_execution.js

@@ -159,7 +159,6 @@
       'src/node_sea.cc',
       'src/node_sea_bin.cc',
       'src/node_serdes.cc',
-      'src/node_shadow_realm.cc',
       'src/node_snapshotable.cc',
       'src/node_sockaddr.cc',
       'src/node_stat_watcher.cc',
@@ -289,7 +288,6 @@
       'src/node_revert.h',
       'src/node_root_certs.h',
       'src/node_sea.h',
-      'src/node_shadow_realm.h',
       'src/node_snapshotable.h',
       'src/node_snapshot_builder.h',
       'src/node_sockaddr.h',