From 091ec548e53e97e6244d87f123ab3749258b9191 Mon Sep 17 00:00:00 2001
From: "Nikolai V." <nikolai.vysotskyi@gmail.com>
Date: Thu, 4 Jun 2026 17:25:58 +0400
Subject: [PATCH] fix(viewCommon): register a fallback default view container
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VS Code's `views` extension-point resolves a contributed view's target as
`container ?? getDefaultViewContainer()`, where getDefaultViewContainer() returns
`viewContainersRegistry.get('workbench.view.explorer')`. In a partial setup
without the files explorer that is undefined, and addViews then reads
`.extensionId` off it — an uncaught TypeError that aborts the entire
contributes.views pass, so every extension's contributed sidebar views fail to
register. Register a minimal hidden-when-empty default Sidebar container under
that id when none exists so the fallback resolves and views degrade gracefully.

Placed in viewCommon so it also covers the workbench service override.

Refs CodinGame/monaco-vscode-api#804
---
 src/service-override/viewCommon.ts | 42 ++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/src/service-override/viewCommon.ts b/src/service-override/viewCommon.ts
index 3bed4ffa..e4884747 100644
--- a/src/service-override/viewCommon.ts
+++ b/src/service-override/viewCommon.ts
@@ -1,5 +1,12 @@
 import type { IEditorOverrideServices } from 'vs/editor/standalone/browser/standaloneServices'
 import { SyncDescriptor } from 'vs/platform/instantiation/common/descriptors'
+import { Registry } from 'vs/platform/registry/common/platform'
+import {
+  Extensions as ViewContainerExtensions,
+  type IViewContainersRegistry,
+  ViewContainerLocation
+} from 'vs/workbench/common/views'
+import { ViewPaneContainer } from 'vs/workbench/browser/parts/views/viewPaneContainer'
 import { IViewDescriptorService } from 'vs/workbench/common/views.service'
 import { ViewDescriptorService } from 'vs/workbench/services/views/browser/viewDescriptorService'
 import { IActivityService } from 'vs/workbench/services/activity/common/activity.service'
@@ -104,7 +111,42 @@ registerServiceInitializePostParticipant(async (accessor) => {
   accessor.get(IHistoryService)
 })
 
+const EXPLORER_VIEW_CONTAINER_ID = 'workbench.view.explorer'
+/**
+ * VS Code's `views` extension-point resolves a contributed view's target as
+ * `container ?? getDefaultViewContainer()`, where getDefaultViewContainer() returns
+ * `viewContainersRegistry.get('workbench.view.explorer')`. In a partial setup that
+ * doesn't include the files explorer, that container is missing and the fallback
+ * throws (it reads `.extensionId` off `undefined`) — uncaught, aborting the ENTIRE
+ * contributes.views pass so every extension's contributed views fail to register.
+ * Register a minimal hidden-when-empty default Sidebar container under that id when
+ * none exists, so the fallback resolves and views degrade gracefully. See #804.
+ */
+function ensureDefaultViewContainer(): void {
+  const registry = Registry.as<IViewContainersRegistry>(
+    ViewContainerExtensions.ViewContainersRegistry
+  )
+  if (registry.get(EXPLORER_VIEW_CONTAINER_ID) != null) {
+    return
+  }
+  registry.registerViewContainer(
+    {
+      id: EXPLORER_VIEW_CONTAINER_ID,
+      title: { value: 'Explorer', original: 'Explorer' },
+      ctorDescriptor: new SyncDescriptor(ViewPaneContainer, [
+        EXPLORER_VIEW_CONTAINER_ID,
+        { mergeViewWithContainerWhenSingleView: true }
+      ]),
+      hideIfEmpty: true,
+      order: 0
+    },
+    ViewContainerLocation.Sidebar,
+    { isDefault: true }
+  )
+}
+
 function getServiceOverride(_webviewIframeAlternateDomains?: string): IEditorOverrideServices {
+  ensureDefaultViewContainer()
   if (_webviewIframeAlternateDomains != null) {
     webviewIframeAlternateDomains = _webviewIframeAlternateDomains
   }