From cab52d1635932e9555a43a5f0d503ceca04a9bf0 Mon Sep 17 00:00:00 2001
From: Neil <4138956+nwparker@users.noreply.github.com>
Date: Sun, 31 May 2026 01:34:31 -0700
Subject: [PATCH] perf: gate contextual copy hint polling (#4024)

---
 .../editor/setup-contextual-copy.test.ts      | 116 ++++++++++++++++++
 .../editor/setup-contextual-copy.ts           |  33 +++--
 2 files changed, 140 insertions(+), 9 deletions(-)

diff --git a/src/renderer/src/components/editor/setup-contextual-copy.test.ts b/src/renderer/src/components/editor/setup-contextual-copy.test.ts
index ce3da798b..8141a2ff3 100644
--- a/src/renderer/src/components/editor/setup-contextual-copy.test.ts
+++ b/src/renderer/src/components/editor/setup-contextual-copy.test.ts
@@ -34,6 +34,122 @@ describe('setupContextualCopy', () => {
     vi.unstubAllGlobals()
   })
 
+  it('does not poll a focused editor when no contextual copy hint is visible', () => {
+    const setInterval = vi.fn(() => 1)
+    vi.stubGlobal('window', {
+      clearInterval: vi.fn(),
+      clearTimeout: vi.fn(),
+      setInterval,
+      setTimeout: vi.fn(() => 2)
+    })
+    vi.stubGlobal('document', {
+      createElement: () => ({
+        className: '',
+        offsetHeight: 28,
+        style: { display: '' },
+        textContent: ''
+      })
+    })
+
+    const editorInstance = {
+      addContentWidget: vi.fn(),
+      getContainerDomNode: () => ({
+        addEventListener: vi.fn(),
+        removeEventListener: vi.fn()
+      }),
+      getModel: () => null,
+      getSelection: () => null,
+      hasTextFocus: () => true,
+      layoutContentWidget: vi.fn(),
+      onDidBlurEditorText: () => ({ dispose: vi.fn() }),
+      onDidChangeCursorSelection: () => ({ dispose: vi.fn() }),
+      onDidDispose: () => ({ dispose: vi.fn() }),
+      onDidFocusEditorText: () => ({ dispose: vi.fn() }),
+      onDidScrollChange: () => ({ dispose: vi.fn() }),
+      removeContentWidget: vi.fn()
+    } as unknown as editor.IStandaloneCodeEditor
+
+    setupContextualCopy({
+      editorInstance,
+      filePath: 'src/example.ts',
+      setCopyToast: vi.fn(),
+      propsRef: {
+        current: {
+          language: 'typescript',
+          relativePath: 'src/example.ts'
+        }
+      },
+      copyToastTimeoutRef: { current: null }
+    })
+
+    expect(setInterval).not.toHaveBeenCalled()
+  })
+
+  it('polls a focused editor while a contextual copy hint is visible', () => {
+    const setInterval = vi.fn(() => 1)
+    vi.stubGlobal('window', {
+      clearInterval: vi.fn(),
+      clearTimeout: vi.fn(),
+      setInterval,
+      setTimeout: vi.fn(() => 2)
+    })
+    vi.stubGlobal('document', {
+      createElement: () => ({
+        className: '',
+        offsetHeight: 28,
+        style: { display: '' },
+        textContent: ''
+      })
+    })
+
+    const selection = {
+      startLineNumber: 1,
+      startColumn: 1,
+      endLineNumber: 2,
+      endColumn: 4,
+      isEmpty: () => false,
+      getStartPosition: () => ({ lineNumber: 1, column: 1 }),
+      getEndPosition: () => ({ lineNumber: 2, column: 4 })
+    }
+    const editorInstance = {
+      addContentWidget: vi.fn(),
+      getContainerDomNode: () => ({
+        addEventListener: vi.fn(),
+        removeEventListener: vi.fn()
+      }),
+      getLayoutInfo: () => ({ height: 500 }),
+      getModel: () => ({
+        getLineMaxColumn: () => 4,
+        getValueInRange: () => 'one\ntwo'
+      }),
+      getScrolledVisiblePosition: () => ({ top: 20, left: 8, height: 16 }),
+      getSelection: () => selection,
+      hasTextFocus: () => true,
+      layoutContentWidget: vi.fn(),
+      onDidBlurEditorText: () => ({ dispose: vi.fn() }),
+      onDidChangeCursorSelection: () => ({ dispose: vi.fn() }),
+      onDidDispose: () => ({ dispose: vi.fn() }),
+      onDidFocusEditorText: () => ({ dispose: vi.fn() }),
+      onDidScrollChange: () => ({ dispose: vi.fn() }),
+      removeContentWidget: vi.fn()
+    } as unknown as editor.IStandaloneCodeEditor
+
+    setupContextualCopy({
+      editorInstance,
+      filePath: 'src/example.ts',
+      setCopyToast: vi.fn(),
+      propsRef: {
+        current: {
+          language: 'typescript',
+          relativePath: 'src/example.ts'
+        }
+      },
+      copyToastTimeoutRef: { current: null }
+    })
+
+    expect(setInterval).toHaveBeenCalledTimes(1)
+  })
+
   it('clears editor-scoped contextual copy cleanup on dispose', () => {
     const clearTimeout = vi.fn()
     const clearInterval = vi.fn()
diff --git a/src/renderer/src/components/editor/setup-contextual-copy.ts b/src/renderer/src/components/editor/setup-contextual-copy.ts
index 6f94b7a5e..b69236617 100644
--- a/src/renderer/src/components/editor/setup-contextual-copy.ts
+++ b/src/renderer/src/components/editor/setup-contextual-copy.ts
@@ -160,13 +160,17 @@ export function setupContextualCopy({
     editorInstance.layoutContentWidget(copyHintWidget)
   }
 
+  const isCopyHintVisible = (): boolean => copyHintNode.style.display === 'block'
+
   const startCopyHintPolling = (): void => {
-    updateCopyHint()
     if (copyHintInterval !== null) {
       return
     }
     copyHintInterval = window.setInterval(() => {
       updateCopyHint()
+      if (!isCopyHintVisible()) {
+        stopCopyHintPolling()
+      }
     }, 150)
   }
 
@@ -177,6 +181,17 @@ export function setupContextualCopy({
     }
   }
 
+  const refreshCopyHintAndPolling = (): void => {
+    updateCopyHint()
+    if (editorInstance.hasTextFocus() && isCopyHintVisible()) {
+      // Why: the interval only tracks a visible content widget. Keeping it
+      // alive while the focused editor has no selection burns idle CPU.
+      startCopyHintPolling()
+    } else {
+      stopCopyHintPolling()
+    }
+  }
+
   const getContextualCopyText = (): string | null => {
     const model = editorInstance.getModel()
     const selection = editorInstance.getSelection()
@@ -262,13 +277,13 @@ export function setupContextualCopy({
     if (getSelectionKey() !== lastCopiedSelectionKey) {
       lastCopiedSelectionKey = null
     }
-    updateCopyHint()
+    refreshCopyHintAndPolling()
   })
   const scrollListener = editorInstance.onDidScrollChange(() => {
-    updateCopyHint()
+    refreshCopyHintAndPolling()
   })
   const focusListener = editorInstance.onDidFocusEditorText(() => {
-    startCopyHintPolling()
+    refreshCopyHintAndPolling()
   })
   const blurListener = editorInstance.onDidBlurEditorText(() => {
     stopCopyHintPolling()
@@ -291,8 +306,8 @@ export function setupContextualCopy({
     void copySelectionWithContext()
   }
   editorDomNode.addEventListener('keydown', handleKeyDown, true)
-  editorDomNode.addEventListener('mouseup', updateCopyHint, true)
-  editorDomNode.addEventListener('keyup', updateCopyHint, true)
+  editorDomNode.addEventListener('mouseup', refreshCopyHintAndPolling, true)
+  editorDomNode.addEventListener('keyup', refreshCopyHintAndPolling, true)
   editorInstance.onDidDispose(() => {
     // Why: Monaco owns these emitters, but disposing explicitly keeps this
     // feature's lifecycle symmetrical with the DOM listener cleanup below.
@@ -312,13 +327,13 @@ export function setupContextualCopy({
       primarySelectionTimer = null
     }
     editorDomNode.removeEventListener('keydown', handleKeyDown, true)
-    editorDomNode.removeEventListener('mouseup', updateCopyHint, true)
-    editorDomNode.removeEventListener('keyup', updateCopyHint, true)
+    editorDomNode.removeEventListener('mouseup', refreshCopyHintAndPolling, true)
+    editorDomNode.removeEventListener('keyup', refreshCopyHintAndPolling, true)
     stopCopyHintPolling()
     editorInstance.removeContentWidget(copyHintWidget)
   })
   if (editorInstance.hasTextFocus()) {
-    startCopyHintPolling()
+    refreshCopyHintAndPolling()
   } else {
     updateCopyHint()
   }