⚡ perf(vscode): 切走的预览文件改了不在后台生成文档，切回来再补一次

vscode/src/codeReader/editor/previewEditor.test.ts

@@ -253,6 +253,13 @@ function tab() {
   }
 }
 
+/** 别处改了这份文件，文档变成 version 版：交给最近打开的预览听着的那个回调 */
+function edit(document: { version: number }, version: number): void {
+  document.version = version
+  const changed = vi.mocked(workspace.onDidChangeTextDocument).mock.calls.at(-1)![0]
+  changed({ document, contentChanges: [{ rangeOffset: 0, rangeLength: 0, text: '// ' }] } as never)
+}
+
 const comparedWithHead = expect.objectContaining({ type: 'diff', diff: expect.objectContaining({ base: '上一次提交' }) })
 
 describe('预览对比什么看这个标签页是从哪儿打开的', () => {
@@ -365,7 +372,7 @@ describe('标签页切走时页面留着', () => {
     expect(commands.executeCommand).not.toHaveBeenCalledWith('setContext', OCCURRENCES_CONTEXT, false)
   })
 
-  it('切走期间文件在别处改了：照常把新的文档发给留着的页面', async () => {
+  it('切走期间文件在别处改了：不生成、不发文档，切回来生成一次发出去', async () => {
     const { provider, document } = opening()
     const page = tab()
     provider.resolveCustomTextEditor(document as never, page.panel)
@@ -373,9 +380,65 @@ describe('标签页切走时页面留着', () => {
 
     page.hide()
     page.clear()
-    document.version = 2
-    const edited = vi.mocked(workspace.onDidChangeTextDocument).mock.calls.at(-1)![0]
-    edited({ document, contentChanges: [{ rangeOffset: 0, rangeLength: 0, text: '// ' }] } as never)
+    vi.mocked(documentMessage).mockClear()
+    edit(document, 2)
+    edit(document, 3)
+    await new Promise(resolve => setTimeout(resolve, 200))
+    expect(documentMessage).not.toHaveBeenCalled()
+    expect(page.posted()).toEqual([])
+
+    page.show()
+    await vi.waitFor(() => expect(page.posted()).toContainEqual(expect.objectContaining({ type: 'document', version: 3 })))
+    expect(documentMessage).toHaveBeenCalledTimes(1)
+  })
+
+  it('改完还没来得及生成就切走了：排着的那次不在后台跑，切回来再生成', async () => {
+    const { provider, document } = opening()
+    const page = tab()
+    provider.resolveCustomTextEditor(document as never, page.panel)
+    await page.send({ type: 'ready' })
+
+    page.clear()
+    vi.mocked(documentMessage).mockClear()
+    edit(document, 2)
+    page.hide()
+    await new Promise(resolve => setTimeout(resolve, 200))
+    expect(documentMessage).not.toHaveBeenCalled()
+
+    page.show()
+    await vi.waitFor(() => expect(page.posted()).toContainEqual(expect.objectContaining({ type: 'document', version: 2 })))
+    expect(documentMessage).toHaveBeenCalledTimes(1)
+  })
+
+  it('切回来时还要滚到别处（跳定义打到它）：等补发的文档一起带过去，不先滚旧的', async () => {
+    const { provider, document } = opening()
+    const page = tab()
+    provider.resolveCustomTextEditor(document as never, page.panel)
+    await page.send({ type: 'ready' })
+
+    page.hide()
+    edit(document, 2)
+    await new Promise(resolve => setTimeout(resolve, 200))
+    page.clear()
+    // 补生成要一会儿：跳过来的位置在生成完之前就到了
+    const generate = vi.mocked(documentMessage).getMockImplementation()!
+    vi.mocked(documentMessage).mockImplementationOnce(async (...args) => {
+      await new Promise(resolve => setTimeout(resolve, 50))
+      return generate(...args)
+    })
+    await provider.open(document.uri as never, { reveal: { line: 1 } }, async () => page.show())
+    await vi.waitFor(() => expect(page.posted()).toContainEqual(expect.objectContaining({ type: 'document', version: 2, reveal: { line: 1 } })))
+    expect(page.posted()).not.toContainEqual(expect.objectContaining({ type: 'reveal' }))
+  })
+
+  it('分屏同时看着：文件改了照常马上更新', async () => {
+    const { provider, document } = opening()
+    const page = tab()
+    provider.resolveCustomTextEditor(document as never, page.panel)
+    await page.send({ type: 'ready' })
+
+    page.clear()
+    edit(document, 2)
     await vi.waitFor(() => expect(page.posted()).toContainEqual(expect.objectContaining({ type: 'document', version: 2 })))
   })