async_hooks: remove legacy AsyncLocalStorage implementation

Remove the async_hooks-based AsyncLocalStorage fallback and the
--no-async-context-frame flag, making AsyncContextFrame the sole
implementation.

Author: mcollina

doc/api/cli.md

@@ -2002,17 +2002,6 @@ Disable the `node-addons` exports condition as well as disable loading
 native addons. When `--no-addons` is specified, calling `process.dlopen` or
 requiring a native C++ addon will fail and throw an exception.
 
-### `--no-async-context-frame`
-
-<!-- YAML
-added: v24.0.0
--->
-
-Disables the use of [`AsyncLocalStorage`][] backed by `AsyncContextFrame` and
-uses the prior implementation which relied on async\_hooks. The previous model
-is retained for compatibility with Electron and for cases where the context
-flow may differ. However, if a difference in flow is found please report it.
-
 ### `--no-deprecation`
 
 <!-- YAML
@@ -3825,7 +3814,6 @@ one is included in the list below.
 * `--napi-modules`
 * `--network-family-autoselection-attempt-timeout`
 * `--no-addons`
-* `--no-async-context-frame`
 * `--no-deprecation`
 * `--no-experimental-global-navigator`
 * `--no-experimental-repl-await`
@@ -4420,7 +4408,6 @@ node --stack-trace-limit=12 -p -e "Error.stackTraceLimit" # prints 12
 [`--require`]: #-r---require-module
 [`--use-env-proxy`]: #--use-env-proxy
 [`--use-system-ca`]: #--use-system-ca
-[`AsyncLocalStorage`]: async_context.md#class-asynclocalstorage
 [`Buffer`]: buffer.md#class-buffer
 [`CRYPTO_secure_malloc_init`]: https://www.openssl.org/docs/man3.0/man3/CRYPTO_secure_malloc_init.html
 [`ERR_INVALID_TYPESCRIPT_SYNTAX`]: errors.md#err_invalid_typescript_syntax

doc/node-config-schema.json

@@ -111,10 +111,6 @@
               "type": "boolean",
               "description": "allow worker threads when any permissions are set"
             },
-            "async-context-frame": {
-              "type": "boolean",
-              "description": "Improve AsyncLocalStorage performance with AsyncContextFrame"
-            },
             "conditions": {
               "oneOf": [
                 {

doc/node.1

@@ -1051,12 +1051,6 @@ Disable the \fBnode-addons\fR exports condition as well as disable loading
 native addons. When \fB--no-addons\fR is specified, calling \fBprocess.dlopen\fR or
 requiring a native C++ addon will fail and throw an exception.
 .
-.It Fl -no-async-context-frame
-Disables the use of \fBAsyncLocalStorage\fR backed by \fBAsyncContextFrame\fR and
-uses the prior implementation which relied on async_hooks. The previous model
-is retained for compatibility with Electron and for cases where the context
-flow may differ. However, if a difference in flow is found please report it.
-.
 .It Fl -no-deprecation
 Silence deprecation warnings.
 .
@@ -2008,8 +2002,6 @@ one is included in the list below.
 .It
 \fB--no-addons\fR
 .It
-\fB--no-async-context-frame\fR
-.It
 \fB--no-deprecation\fR
 .It
 \fB--no-experimental-global-navigator\fR

lib/async_hooks.js

@@ -282,9 +282,7 @@ class AsyncResource {
 module.exports = {
   // Public API
   get AsyncLocalStorage() {
-    return AsyncContextFrame.enabled ?
-      require('internal/async_local_storage/async_context_frame') :
-      require('internal/async_local_storage/async_hooks');
+    return require('internal/async_local_storage/async_context_frame');
   },
   createHook,
   executionAsyncId,

lib/internal/async_context_frame.js

@@ -1,7 +1,6 @@
 'use strict';
 
 const {
-  ObjectSetPrototypeOf,
   SafeMap,
 } = primordials;
 
@@ -10,11 +9,10 @@ const {
   setContinuationPreservedEmbedderData,
 } = internalBinding('async_context_frame');
 
-let enabled_;
-
-class ActiveAsyncContextFrame extends SafeMap {
-  static get enabled() {
-    return true;
+class AsyncContextFrame extends SafeMap {
+  constructor(store, data) {
+    super(AsyncContextFrame.current());
+    this.set(store, data);
   }
 
   static current() {
@@ -35,39 +33,6 @@ class ActiveAsyncContextFrame extends SafeMap {
     const frame = this.current();
     frame?.disable(store);
   }
-}
-
-function checkEnabled() {
-  const enabled = require('internal/options')
-    .getOptionValue('--async-context-frame');
-
-  // If enabled, swap to active prototype so we don't need to check status
-  // on every interaction with the async context frame.
-  if (enabled) {
-    // eslint-disable-next-line no-use-before-define
-    ObjectSetPrototypeOf(AsyncContextFrame, ActiveAsyncContextFrame);
-  }
-
-  return enabled;
-}
-
-class InactiveAsyncContextFrame extends SafeMap {
-  static get enabled() {
-    enabled_ ??= checkEnabled();
-    return enabled_;
-  }
-
-  static current() {}
-  static set(frame) {}
-  static exchange(frame) {}
-  static disable(store) {}
-}
-
-class AsyncContextFrame extends InactiveAsyncContextFrame {
-  constructor(store, data) {
-    super(AsyncContextFrame.current());
-    this.set(store, data);
-  }
 
   disable(store) {
     this.delete(store);

lib/internal/async_local_storage/async_hooks.js

@@ -38,11 +38,6 @@ Local<Value> current(Isolate* isolate) {
 }
 
 void set(Isolate* isolate, Local<Value> value) {
-  auto env = Environment::GetCurrent(isolate);
-  if (!env->options()->async_context_frame) {
-    return;
-  }
-
   isolate->SetContinuationPreservedEmbedderDataV2(value);
 }
 

src/async_context_frame.cc

@@ -739,11 +739,6 @@ EnvironmentOptionsParser::EnvironmentOptionsParser() {
   AddOption(
       "--experimental-wasi-unstable-preview1", "", NoOp{}, kAllowedInEnvvar);
   AddOption("--expose-gc", "expose gc extension", V8Option{}, kAllowedInEnvvar);
-  AddOption("--async-context-frame",
-            "Improve AsyncLocalStorage performance with AsyncContextFrame",
-            &EnvironmentOptions::async_context_frame,
-            kAllowedInEnvvar,
-            true);
   AddOption("--expose-internals", "", &EnvironmentOptions::expose_internals);
   AddOption("--frozen-intrinsics",
             "experimental frozen intrinsics support",

src/node_options.cc

@@ -155,7 +155,6 @@ class EnvironmentOptions : public Options {
   bool allow_worker_threads = false;
   bool experimental_repl_await = true;
   bool experimental_vm_modules = EXPERIMENTALS_DEFAULT_VALUE;
-  bool async_context_frame = true;
   bool expose_internals = false;
   bool force_node_api_uncaught_exceptions_policy = false;
   bool frozen_intrinsics = false;

src/node_options.h

@@ -1,12 +1,11 @@
 'use strict';
-// Flags: --expose_gc --expose-internals
+// Flags: --expose_gc
 
 // This test ensures that AsyncLocalStorage gets gced once it was disabled
 // and no strong references remain in userland.
 
 const common = require('../common');
 const { AsyncLocalStorage } = require('async_hooks');
-const AsyncContextFrame = require('internal/async_context_frame');
 const { onGC } = require('../common/gc');
 
 let asyncLocalStorage = new AsyncLocalStorage();
@@ -17,11 +16,9 @@ asyncLocalStorage.run({}, common.mustCall(() => {
   onGC(asyncLocalStorage, { ongc: common.mustCall() });
 }));
 
-if (AsyncContextFrame.enabled) {
-  // This disable() is needed to remove reference form AsyncContextFrame
-  // created during exit of run() to the AsyncLocalStore instance.
-  asyncLocalStorage.disable();
-}
+// This disable() is needed to remove reference from AsyncContextFrame
+// created during exit of run() to the AsyncLocalStore instance.
+asyncLocalStorage.disable();
 
 asyncLocalStorage = null;
 global.gc();