fix: read nodeIntegrationInWorker from per-frame WebPreferences (#50122) (#50467)

Previously the renderer checked a process-wide command-line switch to
decide whether to create a Node.js environment for dedicated workers.
When a renderer process hosted multiple WebContents with different
nodeIntegrationInWorker values (e.g. via window.open with overridden
webPreferences in setWindowOpenHandler), all workers in the process
used whichever value the first WebContents set on the command line.

Instead, plumb the flag through blink's WorkerSettings at worker
creation time, copying it from the initiating frame's WebPreferences.
The check on the worker thread then reads the per-worker value. Nested
workers inherit the flag from their parent worker via
WorkerSettings::Copy.

The --node-integration-in-worker command-line switch is removed as it
is no longer consumed.

Co-authored-by: Samuel Attard <sam@electronjs.org>

patches/chromium/.patches

@@ -156,3 +156,4 @@ cherry-pick-50b057660b4d.patch
 cherry-pick-45c5a70d984d.patch
 cherry-pick-05e4b544803c.patch
 cherry-pick-5efc7a0127a6.patch
+feat_plumb_node_integration_in_worker_through_workersettings.patch

patches/chromium/feat_plumb_node_integration_in_worker_through_workersettings.patch

@@ -0,0 +1,73 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Samuel Attard <sattard@anthropic.com>
+Date: Sat, 7 Mar 2026 23:07:30 -0800
+Subject: feat: plumb node_integration_in_worker through WorkerSettings
+
+Copy the node_integration_in_worker flag from the initiating frame's
+WebPreferences into WorkerSettings at dedicated worker creation time,
+so the value is readable per-worker on the worker thread rather than
+relying on a process-wide command line switch. The value is also
+propagated to nested workers via WorkerSettings::Copy.
+
+diff --git a/third_party/blink/renderer/core/workers/dedicated_worker.cc b/third_party/blink/renderer/core/workers/dedicated_worker.cc
+index a0f78583334fdf4912b897e88d8ce518773dbfb1..300c5a3b806222e46388d2f0d906737cf282e52e 100644
+--- a/third_party/blink/renderer/core/workers/dedicated_worker.cc
++++ b/third_party/blink/renderer/core/workers/dedicated_worker.cc
+@@ -37,6 +37,7 @@
+ #include "third_party/blink/renderer/core/frame/local_frame_client.h"
+ #include "third_party/blink/renderer/core/frame/web_frame_widget_impl.h"
+ #include "third_party/blink/renderer/core/frame/web_local_frame_impl.h"
++#include "third_party/blink/renderer/core/exported/web_view_impl.h"
+ #include "third_party/blink/renderer/core/inspector/inspector_trace_events.h"
+ #include "third_party/blink/renderer/core/inspector/main_thread_debugger.h"
+ #include "third_party/blink/renderer/core/loader/document_loader.h"
+@@ -555,6 +556,12 @@ DedicatedWorker::CreateGlobalScopeCreationParams(
+     auto* frame = window->GetFrame();
+     parent_devtools_token = frame->GetDevToolsFrameToken();
+     settings = std::make_unique<WorkerSettings>(frame->GetSettings());
++    if (auto* web_local_frame = WebLocalFrameImpl::FromFrame(frame)) {
++      if (auto* web_view = web_local_frame->ViewImpl()) {
++        settings->SetNodeIntegrationInWorker(
++            web_view->GetWebPreferences().node_integration_in_worker);
++      }
++    }
+     agent_group_scheduler_compositor_task_runner =
+         execution_context->GetScheduler()
+             ->ToFrameScheduler()
+diff --git a/third_party/blink/renderer/core/workers/worker_settings.cc b/third_party/blink/renderer/core/workers/worker_settings.cc
+index 45680c5f6ea0c7e89ccf43eb88f8a11e3318c02e..3fa3af62f4e7ba8186441c5e3184b1c04fe32d12 100644
+--- a/third_party/blink/renderer/core/workers/worker_settings.cc
++++ b/third_party/blink/renderer/core/workers/worker_settings.cc
+@@ -40,6 +40,8 @@ std::unique_ptr<WorkerSettings> WorkerSettings::Copy(
+       old_settings->strictly_block_blockable_mixed_content_;
+   new_settings->generic_font_family_settings_ =
+       old_settings->generic_font_family_settings_;
++  new_settings->node_integration_in_worker_ =
++      old_settings->node_integration_in_worker_;
+   return new_settings;
+ }
+ 
+diff --git a/third_party/blink/renderer/core/workers/worker_settings.h b/third_party/blink/renderer/core/workers/worker_settings.h
+index 45c60dd2c44b05fdd279f759069383479823c7f2..33a2a0337efb9a46293e11d0d09b3fc182ab9618 100644
+--- a/third_party/blink/renderer/core/workers/worker_settings.h
++++ b/third_party/blink/renderer/core/workers/worker_settings.h
+@@ -43,6 +43,11 @@ class CORE_EXPORT WorkerSettings {
+     return generic_font_family_settings_;
+   }
+ 
++  bool NodeIntegrationInWorker() const { return node_integration_in_worker_; }
++  void SetNodeIntegrationInWorker(bool value) {
++    node_integration_in_worker_ = value;
++  }
++
+  private:
+   void CopyFlagValuesFromSettings(Settings*);
+ 
+@@ -54,6 +59,7 @@ class CORE_EXPORT WorkerSettings {
+   bool strict_mixed_content_checking_ = false;
+   bool allow_running_of_insecure_content_ = false;
+   bool strictly_block_blockable_mixed_content_ = false;
++  bool node_integration_in_worker_ = false;
+ 
+   GenericFontFamilySettings generic_font_family_settings_;
+ };

shell/browser/web_contents_preferences.cc

@@ -343,9 +343,6 @@ void WebContentsPreferences::AppendCommandLineSwitches(
     command_line->AppendSwitchASCII(::switches::kDisableBlinkFeatures,
                                     *disable_blink_features_);
 
-  if (node_integration_in_worker_)
-    command_line->AppendSwitch(switches::kNodeIntegrationInWorker);
-
   // We are appending args to a webContents so let's save the current state
   // of our preferences object so that during the lifetime of the WebContents
   // we can fetch the options used to initially configure the WebContents

shell/common/options_switches.h

@@ -279,10 +279,6 @@ inline constexpr base::cstring_view kAppPath = "app-path";
 // The command line switch versions of the options.
 inline constexpr base::cstring_view kScrollBounce = "scroll-bounce";
 
-// Command switch passed to renderer process to control nodeIntegration.
-inline constexpr base::cstring_view kNodeIntegrationInWorker =
-    "node-integration-in-worker";
-
 // Widevine options
 // Path to Widevine CDM binaries.
 inline constexpr base::cstring_view kWidevineCdmPath = "widevine-cdm-path";

shell/renderer/electron_renderer_client.cc

@@ -18,7 +18,7 @@
 #include "shell/common/node_bindings.h"
 #include "shell/common/node_includes.h"
 #include "shell/common/node_util.h"
-#include "shell/common/options_switches.h"
+#include "shell/common/v8_util.h"
 #include "shell/renderer/electron_render_frame_observer.h"
 #include "shell/renderer/web_worker_observer.h"
 #include "third_party/blink/public/common/web_preferences/web_preferences.h"
@@ -26,6 +26,8 @@
 #include "third_party/blink/public/web/web_local_frame.h"
 #include "third_party/blink/renderer/core/execution_context/execution_context.h"  // nogncheck
 #include "third_party/blink/renderer/core/frame/web_local_frame_impl.h"  // nogncheck
+#include "third_party/blink/renderer/core/workers/worker_global_scope.h"  // nogncheck
+#include "third_party/blink/renderer/core/workers/worker_settings.h"  // nogncheck
 
 #if BUILDFLAG(IS_LINUX) && (defined(ARCH_CPU_X86_64) || defined(ARCH_CPU_ARM64))
 #define ENABLE_WEB_ASSEMBLY_TRAP_HANDLER_LINUX
@@ -207,44 +209,54 @@ void ElectronRendererClient::WillReleaseScriptContext(
   electron_bindings_->EnvironmentDestroyed(env);
 }
 
-void ElectronRendererClient::WorkerScriptReadyForEvaluationOnWorkerThread(
-    v8::Local<v8::Context> context) {
+namespace {
+
+bool WorkerHasNodeIntegration(blink::ExecutionContext* ec) {
   // We do not create a Node.js environment in service or shared workers
   // owing to an inability to customize sandbox policies in these workers
   // given that they're run out-of-process.
   // Also avoid creating a Node.js environment for worklet global scope
   // created on the main thread.
-  auto* ec = blink::ExecutionContext::From(context);
   if (ec->IsServiceWorkerGlobalScope() || ec->IsSharedWorkerGlobalScope() ||
       ec->IsMainThreadWorkletGlobalScope())
+    return false;
+
+  auto* wgs = blink::DynamicTo<blink::WorkerGlobalScope>(ec);
+  if (!wgs)
+    return false;
+
+  // Read the nodeIntegrationInWorker preference from the worker's settings,
+  // which were copied from the initiating frame's WebPreferences at worker
+  // creation time. This ensures that in-process child windows with different
+  // webPreferences get the correct per-frame value rather than a process-wide
+  // value.
+  auto* worker_settings = wgs->GetWorkerSettings();
+  return worker_settings && worker_settings->NodeIntegrationInWorker();
+}
+
+}  // namespace
+
+void ElectronRendererClient::WorkerScriptReadyForEvaluationOnWorkerThread(
+    v8::Local<v8::Context> context) {
+  auto* ec = blink::ExecutionContext::From(context);
+  if (!WorkerHasNodeIntegration(ec))
     return;
 
-  // This won't be correct for in-process child windows with webPreferences
-  // that have a different value for nodeIntegrationInWorker
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kNodeIntegrationInWorker)) {
-    auto* current = WebWorkerObserver::GetCurrent();
-    if (current)
-      return;
-    WebWorkerObserver::Create()->WorkerScriptReadyForEvaluation(context);
-  }
+  auto* current = WebWorkerObserver::GetCurrent();
+  if (current)
+    return;
+  WebWorkerObserver::Create()->WorkerScriptReadyForEvaluation(context);
 }
 
 void ElectronRendererClient::WillDestroyWorkerContextOnWorkerThread(
     v8::Local<v8::Context> context) {
   auto* ec = blink::ExecutionContext::From(context);
-  if (ec->IsServiceWorkerGlobalScope() || ec->IsSharedWorkerGlobalScope() ||
-      ec->IsMainThreadWorkletGlobalScope())
+  if (!WorkerHasNodeIntegration(ec))
     return;
 
-  // TODO(loc): Note that this will not be correct for in-process child windows
-  // with webPreferences that have a different value for nodeIntegrationInWorker
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kNodeIntegrationInWorker)) {
-    auto* current = WebWorkerObserver::GetCurrent();
-    if (current)
-      current->ContextWillDestroy(context);
-  }
+  auto* current = WebWorkerObserver::GetCurrent();
+  if (current)
+    current->ContextWillDestroy(context);
 }
 
 void ElectronRendererClient::SetUpWebAssemblyTrapHandler() {

spec/chromium-spec.ts

@@ -1372,6 +1372,89 @@ describe('chromium features', () => {
       expect(data).to.equal('object function object function');
     });
 
+    it('Worker does not have node integration when nodeIntegrationInWorker is disabled via setWindowOpenHandler', async () => {
+      const w = new BrowserWindow({
+        show: false,
+        webPreferences: {
+          nodeIntegration: true,
+          nodeIntegrationInWorker: true,
+          contextIsolation: false
+        }
+      });
+
+      w.webContents.setWindowOpenHandler(() => ({
+        action: 'allow',
+        overrideBrowserWindowOptions: {
+          show: false,
+          webPreferences: {
+            nodeIntegration: false,
+            nodeIntegrationInWorker: false,
+            contextIsolation: true
+          }
+        }
+      }));
+
+      await w.loadURL(`file://${fixturesPath}/pages/blank.html`);
+      const childCreated = once(app, 'browser-window-created') as Promise<[any, BrowserWindow]>;
+      w.webContents.executeJavaScript(`window.open(${JSON.stringify(`file://${fixturesPath}/pages/blank.html`)}); void 0;`);
+      const [, child] = await childCreated;
+      await once(child.webContents, 'did-finish-load');
+
+      const data = await child.webContents.executeJavaScript(`
+        const worker = new Worker('../workers/worker_node.js');
+        new Promise((resolve) => { worker.onmessage = e => resolve(e.data); })
+      `);
+      expect(data).to.equal('undefined undefined undefined undefined');
+    });
+
+    it('Worker has node integration when nodeIntegrationInWorker is enabled via setWindowOpenHandler', async () => {
+      const w = new BrowserWindow({
+        show: false,
+        webPreferences: {
+          nodeIntegration: true,
+          nodeIntegrationInWorker: false,
+          contextIsolation: false
+        }
+      });
+
+      w.webContents.setWindowOpenHandler(() => ({
+        action: 'allow',
+        overrideBrowserWindowOptions: {
+          show: false,
+          webPreferences: {
+            nodeIntegration: true,
+            nodeIntegrationInWorker: true,
+            contextIsolation: false
+          }
+        }
+      }));
+
+      await w.loadURL(`file://${fixturesPath}/pages/blank.html`);
+
+      // Parent's workers should NOT have node integration.
+      const parentData = await w.webContents.executeJavaScript(`
+        new Promise((resolve) => {
+          const worker = new Worker('../workers/worker_node.js');
+          worker.onmessage = e => resolve(e.data);
+        })
+      `);
+      expect(parentData).to.equal('undefined undefined undefined undefined');
+
+      const childCreated = once(app, 'browser-window-created') as Promise<[any, BrowserWindow]>;
+      w.webContents.executeJavaScript(`window.open(${JSON.stringify(`file://${fixturesPath}/pages/blank.html`)}); void 0;`);
+      const [, child] = await childCreated;
+      await once(child.webContents, 'did-finish-load');
+
+      // Child's workers should have node integration.
+      const childData = await child.webContents.executeJavaScript(`
+        new Promise((resolve) => {
+          const worker = new Worker('../workers/worker_node.js');
+          worker.onmessage = e => resolve(e.data);
+        })
+      `);
+      expect(childData).to.equal('object function object function');
+    });
+
     it('Worker has access to fetch-dependent interfaces with nodeIntegrationInWorker', async () => {
       const w = new BrowserWindow({
         show: false,