From 84b673b87b12a58314ea7aed4a386f2baca7c80f Mon Sep 17 00:00:00 2001
From: OrcaWin <alpha-eng@stably.ai>
Date: Thu, 29 Oct 2026 16:06:50 -0700
Subject: [PATCH] perf(editor): collect review note elements once per geometry
 pass (#34986)

* perf(editor): collect review note elements once per geometry pass

* test(editor): drop selector call-count tests for review note heights

---------

Co-authored-by: OrcaWin <293788423+OrcaWin@users.noreply.github.com>
---
 .../rich-markdown-review-note-heights.test.ts | 83 +++++++++++++++++++
 .../rich-markdown-review-note-positioning.ts  | 12 ++-
 2 files changed, 91 insertions(+), 4 deletions(-)
 create mode 100644 src/renderer/src/components/editor/rich-markdown-review-note-heights.test.ts

diff --git a/src/renderer/src/components/editor/rich-markdown-review-note-heights.test.ts b/src/renderer/src/components/editor/rich-markdown-review-note-heights.test.ts
new file mode 100644
index 00000000000..07c0cec4100
--- /dev/null
+++ b/src/renderer/src/components/editor/rich-markdown-review-note-heights.test.ts
@@ -0,0 +1,83 @@
+// @vitest-environment happy-dom
+import { Editor } from '@tiptap/core'
+import { afterEach, describe, expect, it, vi } from 'vitest'
+import type { DiffComment } from '../../../../shared/diff-comment-types'
+import { createRichMarkdownExtensions } from './rich-markdown-extensions'
+import { measureRichMarkdownReviewNotePositions } from './rich-markdown-review-note-positioning'
+import { createRichMarkdownEditorCodec } from './rich-markdown-source-transport'
+
+const editors: Editor[] = []
+
+function createEditor() {
+  const editor = new Editor({
+    element: document.createElement('div'),
+    extensions: createRichMarkdownExtensions({ codec: createRichMarkdownEditorCodec() }),
+    content: {
+      type: 'doc',
+      content: [{ type: 'paragraph', content: [{ type: 'text', text: 'Reviewable paragraph' }] }]
+    }
+  })
+  editors.push(editor)
+  vi.spyOn(editor.view, 'coordsAtPos').mockReturnValue({
+    top: 100,
+    bottom: 120,
+    left: 0,
+    right: 10
+  })
+  return editor
+}
+
+function comment(id: string): DiffComment {
+  return {
+    id,
+    worktreeId: 'workspace',
+    filePath: 'notes.md',
+    source: 'markdown',
+    lineNumber: 1,
+    body: 'Review',
+    createdAt: 0,
+    side: 'modified'
+  }
+}
+
+function addCard(container: HTMLElement, id: string, height: number) {
+  const card = document.createElement('div')
+  card.setAttribute('data-rich-markdown-review-note-id', id)
+  const rect = vi
+    .spyOn(card, 'getBoundingClientRect')
+    .mockReturnValue(new DOMRect(0, 0, 10, height))
+  container.append(card)
+  return { card, rect }
+}
+
+afterEach(() => {
+  editors.splice(0).forEach((editor) => editor.destroy())
+  vi.restoreAllMocks()
+})
+
+describe('review note height collection', () => {
+  it('remeasures current cards and preserves first-match and missing-card behavior', () => {
+    const editor = createEditor()
+    const container = document.createElement('div')
+    const markdownComments = [comment('first'), comment('second')]
+    const first = addCard(container, 'first', 20)
+    const duplicate = addCard(container, 'first', 500)
+    const unrelated = addCard(container, 'unrelated', 500)
+    addCard(container, 'second', 30)
+    const measure = () =>
+      measureRichMarkdownReviewNotePositions({
+        editor,
+        container,
+        markdownComments,
+        markdownSourceLineOffset: 0
+      })
+    expect(measure().map((position) => position.top)).toEqual([100, 128])
+    first.rect.mockReturnValue(new DOMRect(0, 0, 10, 100))
+    expect(measure().map((position) => position.top)).toEqual([100, 208])
+    first.card.remove()
+    duplicate.card.remove()
+    expect(measure().map((position) => position.top)).toEqual([100, 210])
+    expect(duplicate.rect).not.toHaveBeenCalled()
+    expect(unrelated.rect).not.toHaveBeenCalled()
+  })
+})
diff --git a/src/renderer/src/components/editor/rich-markdown-review-note-positioning.ts b/src/renderer/src/components/editor/rich-markdown-review-note-positioning.ts
index b7cc8bc63e2..a67109f3ebe 100644
--- a/src/renderer/src/components/editor/rich-markdown-review-note-positioning.ts
+++ b/src/renderer/src/components/editor/rich-markdown-review-note-positioning.ts
@@ -54,10 +54,14 @@ function measureReviewNoteHeights(
   positions: RichMarkdownReviewNotePosition[]
 ): Map<string, number> {
   const measuredHeights = new Map<string, number>()
-  for (const pos of positions) {
-    const el = container.querySelector(`[data-rich-markdown-review-note-id="${pos.comment.id}"]`)
-    if (el) {
-      measuredHeights.set(pos.comment.id, el.getBoundingClientRect().height)
+  if (positions.length === 0) {
+    return measuredHeights
+  }
+  const commentIds = new Set(positions.map((position) => position.comment.id))
+  for (const el of container.querySelectorAll('[data-rich-markdown-review-note-id]')) {
+    const id = el.getAttribute('data-rich-markdown-review-note-id')
+    if (id !== null && commentIds.has(id) && !measuredHeights.has(id)) {
+      measuredHeights.set(id, el.getBoundingClientRect().height)
     }
   }
   return measuredHeights