Fix Monaco Peek References preview collapse (#7662)

Co-authored-by: Orca <help@stably.ai>

src/renderer/src/assets/main.css

@@ -1971,6 +1971,16 @@
   pointer-events: auto;
 }
 
+/* Why: Monaco leaves the peek preview container `inline-block` and only sizes the
+   editor child, so the container shrink-wraps the child in BOTH axes while the
+   inherited automaticLayout ResizeObserver measures the container — a feedback
+   loop that ratchets the preview to blank at fractional zoom/DPI (issue #7405).
+   Pinning both dimensions to the splitview slot severs the loop. */
+.monaco-editor .reference-zone-widget .preview.inline {
+  height: 100%;
+  width: 100%;
+}
+
 /* ── Git conflict decorations ───────────────────────────────────── */
 
 .monaco-editor .orca-conflict-marker-line {

src/renderer/src/lib/monaco-peek-preview-options.test.ts

@@ -0,0 +1,98 @@
+// @vitest-environment happy-dom
+
+import { describe, expect, it, vi } from 'vitest'
+import type * as Monaco from 'monaco-editor'
+import { installMonacoPeekReferencesPreviewOptions } from './monaco-peek-preview-options'
+
+type FakePreviewEditor = Pick<Monaco.editor.ICodeEditor, 'updateOptions'>
+
+type FakeReferenceWidgetInstance = {
+  _preview?: FakePreviewEditor
+  _fillBody?: (containerElement: HTMLElement) => void
+  _revealReference?: (...args: unknown[]) => Promise<unknown>
+}
+
+function createReferenceWidgetConstructor(hooks: {
+  fillBody?: (instance: FakeReferenceWidgetInstance) => void
+  revealReference?: (instance: FakeReferenceWidgetInstance) => Promise<unknown>
+}): {
+  prototype: FakeReferenceWidgetInstance &
+    Required<Pick<FakeReferenceWidgetInstance, '_fillBody' | '_revealReference'>>
+} {
+  return {
+    prototype: {
+      _fillBody(this: FakeReferenceWidgetInstance): void {
+        hooks.fillBody?.(this)
+      },
+      async _revealReference(this: FakeReferenceWidgetInstance): Promise<unknown> {
+        return hooks.revealReference?.(this)
+      }
+    }
+  }
+}
+
+function createPreviewEditor(): FakePreviewEditor {
+  return { updateOptions: vi.fn() }
+}
+
+const peekPreviewOptions = {
+  smoothScrolling: false,
+  stickyScroll: { enabled: false },
+  wordWrap: 'off'
+}
+
+describe('installMonacoPeekReferencesPreviewOptions', () => {
+  it('updates the embedded preview after ReferenceWidget creates it', () => {
+    const preview = createPreviewEditor()
+    const referenceWidget = createReferenceWidgetConstructor({
+      fillBody(instance) {
+        instance._preview = preview
+      }
+    })
+
+    installMonacoPeekReferencesPreviewOptions(referenceWidget)
+    referenceWidget.prototype._fillBody(document.createElement('div'))
+
+    expect(preview.updateOptions).toHaveBeenCalledWith(peekPreviewOptions)
+  })
+
+  it('updates the embedded preview before revealing a reference', async () => {
+    const calls: string[] = []
+    const preview: FakePreviewEditor = {
+      updateOptions: vi.fn(() => calls.push('updateOptions'))
+    }
+    const referenceWidget = createReferenceWidgetConstructor({
+      revealReference: async () => {
+        calls.push('revealReference')
+      }
+    })
+    referenceWidget.prototype._preview = preview
+
+    installMonacoPeekReferencesPreviewOptions(referenceWidget)
+    await referenceWidget.prototype._revealReference('reference')
+
+    expect(calls).toEqual(['updateOptions', 'revealReference', 'updateOptions'])
+    expect(preview.updateOptions).toHaveBeenCalledWith(peekPreviewOptions)
+  })
+
+  it('skips patching when the private Monaco hooks are missing', () => {
+    const referenceWidget: { prototype: FakeReferenceWidgetInstance } = { prototype: {} }
+
+    installMonacoPeekReferencesPreviewOptions(referenceWidget)
+
+    expect(referenceWidget.prototype._fillBody).toBeUndefined()
+    expect(referenceWidget.prototype._revealReference).toBeUndefined()
+  })
+
+  it('does not wrap ReferenceWidget more than once', async () => {
+    const preview = createPreviewEditor()
+    const referenceWidget = createReferenceWidgetConstructor({})
+    referenceWidget.prototype._preview = preview
+
+    installMonacoPeekReferencesPreviewOptions(referenceWidget)
+    installMonacoPeekReferencesPreviewOptions(referenceWidget)
+    await referenceWidget.prototype._revealReference('reference')
+
+    expect(preview.updateOptions).toHaveBeenCalledTimes(2)
+  })
+})

src/renderer/src/lib/monaco-peek-preview-options.ts

@@ -0,0 +1,67 @@
+import type * as Monaco from 'monaco-editor'
+import { ReferenceWidget as MonacoReferenceWidget } from 'monaco-editor/esm/vs/editor/contrib/gotoSymbol/browser/peek/referencesWidget.js'
+
+type PeekPreviewEditor = Pick<Monaco.editor.ICodeEditor, 'updateOptions'>
+
+const PEEK_REFERENCES_PREVIEW_OPTIONS: Monaco.editor.IEditorOptions = {
+  smoothScrolling: false,
+  stickyScroll: { enabled: false },
+  wordWrap: 'off'
+}
+
+type ReferenceWidgetInstance = {
+  _preview?: PeekPreviewEditor
+  _fillBody?: (containerElement: HTMLElement) => void
+  _revealReference?: (...args: unknown[]) => Promise<unknown>
+}
+
+type ReferenceWidgetConstructor = {
+  prototype: ReferenceWidgetInstance & {
+    __orcaPeekPreviewOptionsInstalled?: true
+  }
+}
+
+function applyPeekReferencesPreviewOptions(editor: PeekPreviewEditor | undefined): void {
+  // Why: Monaco embedded editors inherit Orca's full-editor options first.
+  // Peek previews are transient readers, so keep scroll/wrap widgets out of them.
+  editor?.updateOptions(PEEK_REFERENCES_PREVIEW_OPTIONS)
+}
+
+export function installMonacoPeekReferencesPreviewOptions(
+  referenceWidget: ReferenceWidgetConstructor = MonacoReferenceWidget as unknown as ReferenceWidgetConstructor
+): void {
+  const prototype = referenceWidget.prototype
+  if (prototype.__orcaPeekPreviewOptionsInstalled) {
+    return
+  }
+
+  const originalFillBody = prototype._fillBody
+  const originalRevealReference = prototype._revealReference
+  // Why: these are private Monaco members with no stability guarantee; if an
+  // upgrade removes either, skip patching so Peek keeps Monaco's defaults.
+  if (typeof originalFillBody !== 'function' || typeof originalRevealReference !== 'function') {
+    return
+  }
+
+  prototype._fillBody = function fillBodyWithPeekPreviewOptions(
+    this: ReferenceWidgetInstance,
+    containerElement: HTMLElement
+  ): void {
+    originalFillBody.call(this, containerElement)
+    applyPeekReferencesPreviewOptions(this._preview)
+  }
+
+  prototype._revealReference = async function revealReferenceWithPeekPreviewOptions(
+    this: ReferenceWidgetInstance,
+    ...args: unknown[]
+  ): Promise<unknown> {
+    applyPeekReferencesPreviewOptions(this._preview)
+    try {
+      return await originalRevealReference.apply(this, args)
+    } finally {
+      applyPeekReferencesPreviewOptions(this._preview)
+    }
+  }
+
+  prototype.__orcaPeekPreviewOptionsInstalled = true
+}

src/renderer/src/lib/monaco-setup.ts

@@ -13,6 +13,7 @@ import { registerSvelteLanguage } from './monaco-languages/register-svelte'
 import { registerVueLanguage } from './monaco-languages/register-vue'
 import { installMonacoDelayerCancellationGuard } from './monaco-delayer-cancellation-guard'
 import { installMonacoDiffEditorDisposalGuard } from './monaco-diff-editor-disposal'
+import { installMonacoPeekReferencesPreviewOptions } from './monaco-peek-preview-options'
 import { installMonacoContextMenuPaste } from '@/components/editor/install-monaco-context-menu-paste'
 
 globalThis.MonacoEnvironment = {
@@ -78,6 +79,7 @@ registerAstroLanguage(monaco)
 registerNimLanguage(monaco)
 installMonacoDelayerCancellationGuard()
 installMonacoDiffEditorDisposalGuard(monaco)
+installMonacoPeekReferencesPreviewOptions()
 // Why: Monaco's built-in context-menu Paste reads navigator.clipboard, which is
 // blocked in Orca's sandboxed renderer. Route it through the trusted IPC bridge
 // so right-click Paste works like Cmd+V (which already works via native events).