feat(chat): 在会话顶栏显示当前 Git 分支

apps/desktop/electron/main/git-branch.ts

@@ -0,0 +1,36 @@
+import { readFile } from "node:fs/promises";
+import { join, resolve } from "node:path";
+
+async function resolveGitDirectory(workspacePath: string): Promise<string> {
+  const dotGitPath = join(workspacePath, ".git");
+
+  try {
+    const pointer = await readFile(dotGitPath, "utf8");
+    const match = pointer.match(/^gitdir:\s*(.+)$/m);
+    if (match?.[1]) {
+      return resolve(workspacePath, match[1].trim());
+    }
+  } catch {
+    // Standard repositories store .git as a directory, so reading it fails.
+  }
+
+  return dotGitPath;
+}
+
+export async function withGitBranch<
+  T extends { path?: string; name?: string } | null | undefined,
+>(workspace: T): Promise<T> {
+  if (!workspace || !workspace.path) return workspace;
+
+  try {
+    const gitDirectory = await resolveGitDirectory(workspace.path);
+    const head = await readFile(join(gitDirectory, "HEAD"), "utf8");
+    const match = head.match(/ref:\s*refs\/heads\/(.+)$/m);
+    return {
+      ...workspace,
+      branch: match?.[1]?.trim() || "detached",
+    };
+  } catch {
+    return { ...workspace, branch: undefined };
+  }
+}

apps/desktop/electron/main/index.ts

@@ -52,6 +52,7 @@ import { PersistenceOutbox } from "./persistence-outbox";
 import { AgentSidecar } from "./agent-sidecar";
 import { Logger, ignoreBrokenStdio } from "./logger";
 import { installMainProcessErrorHandlers } from "./main-process-errors";
+import { withGitBranch } from "./git-branch";
 import {
   isDbSchemaTooNewError,
 } from "./host-boot-diagnostics";
@@ -1059,24 +1060,6 @@ const {
   isStaleTerminalEvent,
 } = sessionCoordination;
 
-async function withGitBranch<T extends { path?: string; name?: string } | null | undefined>(
-  workspace: T,
-): Promise<T> {
-  if (!workspace || !workspace.path) return workspace;
-  try {
-    const { readFile } = await import("node:fs/promises");
-    const { join } = await import("node:path");
-    const head = await readFile(join(workspace.path, ".git/HEAD"), "utf8");
-    const match = head.match(/ref:\s*refs\/heads\/(.+)$/m);
-    return {
-      ...workspace,
-      branch: match?.[1]?.trim() || "detached",
-    };
-  } catch {
-    return { ...workspace, branch: undefined };
-  }
-}
-
 /**
  * Applies a close-behavior choice. The tray icon is owned by D216 and stays
  * resident on every platform, so switching to "quit" must not destroy it —

apps/desktop/src/components/ConversationTopbar.tsx

@@ -1,7 +1,9 @@
+import { useEffect } from "react";
 import { useTranslation } from "react-i18next";
 import { useAppStore } from "../stores/app-store";
 import {
   IconSidebar,
+  IconBranch,
   IconNewSession,
   IconSearch,
 } from "./icons";
@@ -37,13 +39,26 @@ export function ConversationTopbar({
   const activeSessionId = useAppStore((s) => s.activeSessionId);
   const sessions = useAppStore((s) => s.sessions);
   const workspace = useAppStore((s) => s.workspace);
+  const refreshProject = useAppStore((s) => s.refreshProject);
 
   const activeSession = sessions.find((session) => session.id === activeSessionId);
+  const projectPath = workspace?.path;
+
+  useEffect(() => {
+    if (!projectPath) return;
+    const refreshBranch = () => {
+      void refreshProject(projectPath);
+    };
+    refreshBranch();
+    window.addEventListener("focus", refreshBranch);
+    return () => window.removeEventListener("focus", refreshBranch);
+  }, [activeSessionId, projectPath, refreshProject]);
 
   const fullTaskTitle = isDefaultSessionTitle(activeSession?.title)
     ? t("chat.untitledTask")
     : activeSession?.title || t("chat.untitledTask");
   const project = projectName(workspace?.path, workspace?.name);
+  const branch = workspace?.branch?.trim();
 
   return (
     <div
@@ -76,6 +91,16 @@ export function ConversationTopbar({
           title={project ? `${project} · ${fullTaskTitle}` : fullTaskTitle}
         >
           <span className="ct-title">{fullTaskTitle}</span>
+          {branch ? (
+            <span
+              className="ct-branch"
+              aria-label={t("nav.hoverCardBranchAria", { name: branch })}
+              title={branch}
+            >
+              <IconBranch size={12} aria-hidden />
+              <span>{branch}</span>
+            </span>
+          ) : null}
         </div>
       </div>
 

apps/desktop/src/styles/chrome.css

@@ -487,7 +487,7 @@
 .conversation-topbar .ct-title-wrap {
   display: flex;
   align-items: center;
-  gap: 0;
+  gap: 8px;
   flex: 1 1 auto;
   min-width: 0;
   overflow: hidden;
@@ -498,7 +498,7 @@
 
 .conversation-topbar .ct-title {
   min-width: 0;
-  flex: 1 1 auto;
+  flex: 0 1 auto;
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
@@ -509,6 +509,31 @@
   line-height: var(--leading-compact);
 }
 
+.conversation-topbar .ct-branch {
+  display: inline-flex;
+  height: 20px;
+  max-width: min(180px, 32vw);
+  min-width: 0;
+  flex: 0 1 auto;
+  align-items: center;
+  gap: 4px;
+  overflow: hidden;
+  border: 1px solid var(--ds-border-subtle);
+  border-radius: var(--radius-pill);
+  padding: 0 7px;
+  background: var(--ds-bg-secondary);
+  color: var(--ds-text-secondary);
+  font-size: var(--text-sm);
+  line-height: var(--leading-compact);
+}
+
+.conversation-topbar .ct-branch > span {
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
 /* One geometry and one seat for every chrome icon control: the topbar's dock
    toggle, the viewport-fixed work-panel toggle, the preview/route-band lane
    actions, and the work-panel header's create and maximize controls. The seat is

apps/desktop/test/app-store-sidebar.test.mjs

@@ -17,6 +17,10 @@ const topbarSource = await readFile(
   new URL("../src/components/ConversationTopbar.tsx", import.meta.url),
   "utf8",
 );
+const stylesSource = await readFile(
+  new URL("../src/styles/chrome.css", import.meta.url),
+  "utf8",
+);
 
 test("project activation separates visible transcript state from background run state", () => {
   const activationBlock = storeSource.match(
@@ -97,6 +101,17 @@ test("global search stays on the conversation topbar, not the sidebar header", (
   assert.match(topbarSource, /ariaLabel=\{t\("nav\.search"\)\}/);
 });
 
+test("conversation topbar shows and refreshes the active project's git branch", () => {
+  assert.match(topbarSource, /const branch = workspace\?\.branch\?\.trim\(\)/);
+  assert.match(topbarSource, /refreshProject\(projectPath\)/);
+  assert.match(topbarSource, /window\.addEventListener\("focus", refreshBranch\)/);
+  assert.match(topbarSource, /className="ct-branch"/);
+  assert.match(topbarSource, /hoverCardBranchAria/);
+  assert.match(topbarSource, /<IconBranch/);
+  assert.match(stylesSource, /\.conversation-topbar \.ct-branch\s*\{/);
+  assert.match(stylesSource, /text-overflow:\s*ellipsis/);
+});
+
 test("project rows expose press-and-move title drag and keyboard reorder behavior", () => {
   assert.doesNotMatch(sidebarSource, /sidebar-project-drag-handle/);
   assert.doesNotMatch(sidebarSource, /IconGripVertical/);

apps/desktop/test/git-branch.test.mjs

@@ -0,0 +1,52 @@
+import assert from "node:assert/strict";
+import { mkdtemp, mkdir, rm, writeFile } from "node:fs/promises";
+import { register } from "node:module";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import test from "node:test";
+
+register(new URL("./helpers/ts-import-hooks.mjs", import.meta.url));
+
+const { withGitBranch } = await import("../electron/main/git-branch.ts");
+
+test("reads branches from standard repositories and git worktrees", async () => {
+  const root = await mkdtemp(join(tmpdir(), "pi-git-branch-"));
+  try {
+    const standard = join(root, "standard");
+    await mkdir(join(standard, ".git"), { recursive: true });
+    await writeFile(join(standard, ".git", "HEAD"), "ref: refs/heads/feature/standard\n");
+    assert.deepEqual(
+      await withGitBranch({ path: standard, name: "standard" }),
+      { path: standard, name: "standard", branch: "feature/standard" },
+    );
+
+    const worktree = join(root, "worktree");
+    const metadata = join(root, "metadata");
+    await mkdir(worktree);
+    await mkdir(metadata);
+    await writeFile(join(worktree, ".git"), "gitdir: ../metadata\n");
+    await writeFile(join(metadata, "HEAD"), "ref: refs/heads/fix/worktree\n");
+    assert.deepEqual(
+      await withGitBranch({ path: worktree, name: "worktree" }),
+      { path: worktree, name: "worktree", branch: "fix/worktree" },
+    );
+
+    await writeFile(join(metadata, "HEAD"), "0123456789abcdef\n");
+    assert.equal((await withGitBranch({ path: worktree }))?.branch, "detached");
+  } finally {
+    await rm(root, { recursive: true, force: true });
+  }
+});
+
+test("keeps non-git workspaces usable without a branch", async () => {
+  const root = await mkdtemp(join(tmpdir(), "pi-no-git-branch-"));
+  try {
+    assert.deepEqual(
+      await withGitBranch({ path: root, name: "folder" }),
+      { path: root, name: "folder", branch: undefined },
+    );
+    assert.equal(await withGitBranch(null), null);
+  } finally {
+    await rm(root, { recursive: true, force: true });
+  }
+});

docs/spec/04-ux/08-component-spec.md

@@ -224,15 +224,16 @@ See [ADR tray-session-shortcuts](/adr/tray-session-shortcuts).
 
 ### 2.1 Purpose
 
-Global controls bar: task title and window actions. Project scope remains
-available in the title tooltip. The active session's Agent/Plan/Goal control and
-model selection belong to the Composer. (Settings is reached from the command
-palette / application menu, not the top bar.)
+Global controls bar: task title, the active Git branch when available, and
+window actions. Project scope remains available in the title tooltip. The active
+session's Agent/Plan/Goal control and model selection belong to the Composer.
+(Settings is reached from the command palette / application menu, not the top
+bar.)
 
 ### 2.2 Anatomy
 
 ```text
-[☰ Sidebar] [Task title]                          [＋ New] [🔍 Search]
+[☰ Sidebar] [Task title] [⑂ branch]              [＋ New] [🔍 Search]
 ```
 
 (Icons described functionally; actual render uses Lucide SVGs. The `[☰ Sidebar]`
@@ -242,10 +243,13 @@ expanded it owns that control, so the top bar does not duplicate it. The
 does not duplicate it. Keyboard shortcuts and the application menu remain
 available.)
 
-The conversation top bar renders for the chat route only; Pull requests, Scheduled,
-Plugins, and Settings keep the frameless drag band. It owns the task title and
-window actions only. Project scope remains in the title tooltip instead of adding
-another visible label. The Composer owns the Agent/Plan/Goal control and the
+The conversation top bar renders for the chat route only; Pull requests,
+Scheduled, Plugins, and Settings keep the frameless drag band. It owns the task
+title, a compact Git branch badge for the active project, and window actions.
+The full project scope remains in the title tooltip. The branch badge is omitted
+for temporary sessions and non-Git folders. It refreshes when a session is
+selected and when the window regains focus, so a branch changed outside the app
+does not remain stale. The Composer owns the Agent/Plan/Goal control and the
 combined model × reasoning selection (§11).
 
 ### 2.3 Layout
@@ -271,15 +275,17 @@ combined model × reasoning selection (§11).
   overlay hiding tabs or panel actions.
   Resource close actions stay in their tabs so a second header `×` does not echo
   the native Windows close control (D357).
-- Title cluster (task title) flexes to the remaining width after toolbar
-  reservations (sidebar lead-in, action icons, work-panel toggle, and
-  platform window controls). The visible title uses CSS ellipsis only when
-  that width overflows; the full title remains in the native tooltip.
+- Title cluster (task title plus optional branch badge) flexes to the remaining
+  width after toolbar reservations (sidebar lead-in, action icons, work-panel
+  toggle, and platform window controls). The visible task title uses CSS
+  ellipsis only when that width overflows; the full title remains in the native
+  tooltip. The branch badge keeps its icon and ellipsizes long branch names
+  within 180px.
   The right cluster (action icons) is `flex: 0 0 auto`
   and is never squeezed by a long title. The conversation surface keeps a
   `min-width` so its content is not crushed on narrow windows.
-- Project scope is available from the title tooltip but is not rendered as a
-  second visible label.
+- Project scope is available from the title tooltip. Only its current Git branch
+  is repeated visibly, as a compact badge rather than a second project label.
 - macOS fullscreen resets the left reserve to 8px (mirrors the sidebar header).
 - Sticky: `z-sticky`
 - Items: left-aligned controls, right-aligned actions
@@ -322,6 +328,7 @@ combined model × reasoning selection (§11).
 | Element | Default | Running | Error | No workspace |
 |---|---|---|---|---|
 | Task title | session title (or untitled), uses the available width, with an ellipsis only on overflow | same | same | same |
+| Git branch | current active-project branch | same, refreshed on window focus | same | omitted |
 | New task / Search | icon buttons | same | same | same |
 | Composer stop control | hidden | visible only when the running composer draft is empty | hidden | hidden |
 | Project name | title tooltip only | same | same | omitted |

docs/spec/06-delivery/04-e2e-test-plan.md

@@ -14129,3 +14129,23 @@ the latest destination. These assertions measure work counts, not device FPS.
 - **Milestone**: Maintenance.
 - **Status**: Covered by the existing HTTP client integration fixture and a
   focused component-render validation; no live IDA process required.
+### E2E-CHAT-active-git-branch
+
+- **Preconditions:** An isolated Git project (including a linked worktree) with
+  one project-bound session and one temporary session; no provider credentials.
+- **Steps:** Open the project session, switch its branch outside PI-Desktop,
+  refocus the app, then open the temporary session. Repeat with a long branch
+  name and a non-Git folder.
+- **Expected:** The conversation topbar shows the active project's current
+  branch beside the task title, refreshes after focus, and ellipsizes long names
+  without displacing New/Search. Temporary sessions and non-Git folders show no
+  branch badge. The Composer keeps its existing no-workspace-rail contract.
+- **Specs:** 04-ux/08-component-spec.md, Topbar.
+- **Acceptance:** The project session exposes enough branch context to avoid
+  operating in the wrong checkout.
+- **Milestone:** Post-MVP maintenance.
+- **Automation:** apps/desktop/test/app-store-sidebar.test.mjs covers the
+  renderer/store contract; apps/desktop/test/git-branch.test.mjs covers standard
+  repositories, linked worktrees, detached HEAD, and non-Git folders.
+- **Status:** Implemented. Native macOS project/worktree badge and truncation
+  visually qualified; Windows/Linux not qualified.

docs/zh-CN/spec/04-ux/08-component-spec.md

@@ -210,10 +210,11 @@ See [ADR tray-session-shortcuts](/adr/tray-session-shortcuts).
 chrome 搜索入口；展开的侧边栏标题不再重复该控件。键盘快捷键
 和应用菜单仍然可用。）
 
-对话顶部栏仅针对聊天路线呈现；拉取请求、已计划、
-插件和设置保留无框拖带。它仅拥有任务标题和窗口操作。
-项目范围仍通过标题工具提示提供，而不是添加另一个可见标签。
-Composer 拥有 Agent/Plan/Goal 控件以及组合的模型 × 推理选择（§11）。
+对话顶部栏仅针对聊天路线呈现；拉取请求、已计划、插件和设置保留无框拖带。
+它包含任务标题、当前项目的紧凑 Git 分支标记和窗口操作。完整项目范围仍通过
+标题工具提示提供。临时会话和非 Git 文件夹不显示分支标记；选择会话以及窗口
+重新获得焦点时会刷新分支，避免应用外切换分支后继续显示旧值。Composer 拥有
+Agent/Plan/Goal 控件以及组合的模型 × 推理选择（§11）。
 
 ### 2.3 布局
 
@@ -224,12 +225,12 @@ Composer 拥有 Agent/Plan/Goal 控件以及组合的模型 × 推理选择（§
   交互式控件上的 `no-drag`； macOS 仅在侧边栏折叠时保留左侧 88px 的交通
   灯空间，Windows/Linux保留权利
   本机窗口控件为 112px
-- 标题簇（任务标题）在预留侧边栏引导、操作图标、工作面板开关和平台窗口控件之后，占用剩余宽度。可见标题仅在该宽度溢出时使用 CSS 省略号；完整标题保留在本机工具提示中。
+- 标题簇包含任务标题和可选分支标记，在预留侧边栏引导、操作图标、工作面板开关和平台窗口控件之后，占用剩余宽度。可见任务标题仅在该宽度溢出时使用 CSS 省略号；完整标题保留在本机工具提示中。长分支名在 180px 内省略。
   右侧集群（操作图标）是 `flex: 0 0 auto`
   并且永远不会被长标题所挤压。对话表面保持
   `min-width` 因此其内容不会在狭窄的窗口上被压垮。
-- 项目范围可从标题工具提示中获取，但不会呈现为
-  第二个可见标签。
+- 项目范围可从标题工具提示中获取；只有当前 Git 分支会以紧凑标记重复显示，
+  不额外显示第二个项目标签。
 - macOS 全屏将左侧保留重置为 8px（镜像侧边栏标题）。
 - 置顶：`z-sticky`
 - 项目：左对齐控件、右对齐操作
@@ -258,6 +259,7 @@ Composer 拥有 Agent/Plan/Goal 控件以及组合的模型 × 推理选择（§
 | 元素 | 默认 | 跑步 | 错误 | 没有工作空间 |
 |---|---|---|---|---|
 | 任务标题 | 会话标题（或无标题），使用可用宽度，仅在溢出时显示省略号 | 相同，加上一个紧凑的脉冲状态点 | 一样 | 一样 |
+| Git 分支 | 当前活动项目分支 | 相同，窗口聚焦时刷新 | 一样 | 省略 |
 | 新任务/搜索 | 图标按钮 | 一样 | 一样 | 一样 |
 | Composer 停止控件 | 隐藏的 | 仅在运行中的草稿为空时可见 | 隐藏的 | 隐藏的 |
 | 项目名称 | 仅标题工具提示 | 一样 | 一样 | 省略 |