feat(ext/sw): GitHost.lastCommit() for vault-presence metadata

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

extension/src/service-worker/__tests__/git-host-extensions.test.ts

@@ -0,0 +1,55 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { GiteaHost } from '../gitea';
+import { GitHubHost } from '../github';
+
+describe('lastCommit (Gitea)', () => {
+  let fetchSpy: ReturnType<typeof vi.spyOn>;
+
+  beforeEach(() => {
+    fetchSpy = vi.spyOn(globalThis, 'fetch');
+  });
+
+  it('returns commit metadata when API succeeds', async () => {
+    fetchSpy.mockResolvedValueOnce(new Response(JSON.stringify([
+      { sha: 'abc1234567', commit: { author: { name: 'Alice', date: '2026-04-20T12:00:00Z' } } },
+    ]), { status: 200 }));
+    const host = new GiteaHost('https://git.example.com', 'user/vault', 'tok');
+    const result = await host.lastCommit('manifest.enc');
+    expect(result).toEqual({ sha: 'abc1234', author: 'Alice', date: '2026-04-20T12:00:00Z' });
+  });
+
+  it('returns null on 404', async () => {
+    fetchSpy.mockResolvedValueOnce(new Response('', { status: 404 }));
+    const host = new GiteaHost('https://git.example.com', 'user/vault', 'tok');
+    expect(await host.lastCommit('manifest.enc')).toBeNull();
+  });
+
+  it('returns null on network error', async () => {
+    fetchSpy.mockRejectedValueOnce(new Error('network'));
+    const host = new GiteaHost('https://git.example.com', 'user/vault', 'tok');
+    expect(await host.lastCommit('manifest.enc')).toBeNull();
+  });
+});
+
+describe('lastCommit (GitHub)', () => {
+  let fetchSpy: ReturnType<typeof vi.spyOn>;
+
+  beforeEach(() => {
+    fetchSpy = vi.spyOn(globalThis, 'fetch');
+  });
+
+  it('returns commit metadata when API succeeds', async () => {
+    fetchSpy.mockResolvedValueOnce(new Response(JSON.stringify([
+      { sha: 'def4567890', commit: { author: { name: 'Bob', date: '2026-04-22T15:00:00Z' } } },
+    ]), { status: 200 }));
+    const host = new GitHubHost('user/vault', 'tok');
+    const result = await host.lastCommit('manifest.enc');
+    expect(result).toEqual({ sha: 'def4567', author: 'Bob', date: '2026-04-22T15:00:00Z' });
+  });
+
+  it('returns null when commits list is empty', async () => {
+    fetchSpy.mockResolvedValueOnce(new Response(JSON.stringify([]), { status: 200 }));
+    const host = new GitHubHost('user/vault', 'tok');
+    expect(await host.lastCommit('manifest.enc')).toBeNull();
+  });
+});

extension/src/service-worker/git-host.ts

@@ -17,6 +17,11 @@ export interface GitHost {
   /// List file names in a directory (non-recursive).
   listDir(path: string): Promise<string[]>;
 
+  /// Best-effort: returns metadata for the most recent commit touching `path`.
+  /// Returns null if the path has no commits, the API fails, or the host
+  /// doesn't support the lookup. Callers must tolerate null.
+  lastCommit(path: string): Promise<{ sha: string; author: string; date: string } | null>;
+
   /// Write an opaque binary blob to the repo. Optimized for large
   /// attachments — implementations switch from Contents API to Git
   /// Data API when content exceeds BLOB_THRESHOLD_BYTES.

extension/src/service-worker/gitea.ts

@@ -16,14 +16,17 @@ import { uint8ArrayToBase64, base64ToUint8Array, BLOB_THRESHOLD_BYTES } from './
 export class GiteaHost implements GitHost {
   private baseUrl: string;
   private gitApiBase: string;
+  private commitsUrl: string;
   private branch: string = 'main';
   private headers: Record<string, string>;
 
   constructor(hostUrl: string, repoPath: string, apiToken: string) {
     // Remove trailing slash from hostUrl
     const host = hostUrl.replace(/\/+$/, '');
-    this.baseUrl = `${host}/api/v1/repos/${repoPath}/contents`;
-    this.gitApiBase = `${host}/api/v1/repos/${repoPath}/git`;
+    const apiUrl = `${host}/api/v1`;
+    this.baseUrl = `${apiUrl}/repos/${repoPath}/contents`;
+    this.gitApiBase = `${apiUrl}/repos/${repoPath}/git`;
+    this.commitsUrl = `${apiUrl}/repos/${repoPath}/commits`;
     this.headers = {
       'Authorization': `token ${apiToken}`,
       'Content-Type': 'application/json',
@@ -115,6 +118,24 @@ export class GiteaHost implements GitHost {
     return json.map((item: { name: string }) => item.name);
   }
 
+  async lastCommit(path: string): Promise<{ sha: string; author: string; date: string } | null> {
+    try {
+      const url = `${this.commitsUrl}?path=${encodeURIComponent(path)}&limit=1`;
+      const resp = await fetch(url, { headers: this.headers });
+      if (!resp.ok) return null;
+      const json = await resp.json();
+      if (!Array.isArray(json) || json.length === 0) return null;
+      const c = json[0];
+      return {
+        sha: String(c.sha).slice(0, 7),
+        author: c.commit?.author?.name ?? 'unknown',
+        date: c.commit?.author?.date ?? '',
+      };
+    } catch {
+      return null;
+    }
+  }
+
   async putBlob(path: string, content: Uint8Array, message: string): Promise<string> {
     if (content.length <= BLOB_THRESHOLD_BYTES) {
       await this.writeFile(path, content, message);

extension/src/service-worker/github.ts

@@ -14,12 +14,14 @@ import { uint8ArrayToBase64, base64ToUint8Array, BLOB_THRESHOLD_BYTES } from './
 export class GitHubHost implements GitHost {
   private baseUrl: string;
   private gitApiBase: string;
+  private commitsUrl: string;
   private branch: string = 'main';
   private headers: Record<string, string>;
 
   constructor(repoPath: string, apiToken: string) {
     this.baseUrl = `https://api.github.com/repos/${repoPath}/contents`;
     this.gitApiBase = `https://api.github.com/repos/${repoPath}/git`;
+    this.commitsUrl = `https://api.github.com/repos/${repoPath}/commits`;
     this.headers = {
       'Authorization': `Bearer ${apiToken}`,
       'Content-Type': 'application/json',
@@ -109,6 +111,24 @@ export class GitHubHost implements GitHost {
     return json.map((item: { name: string }) => item.name);
   }
 
+  async lastCommit(path: string): Promise<{ sha: string; author: string; date: string } | null> {
+    try {
+      const url = `${this.commitsUrl}?path=${encodeURIComponent(path)}&per_page=1`;
+      const resp = await fetch(url, { headers: this.headers });
+      if (!resp.ok) return null;
+      const json = await resp.json();
+      if (!Array.isArray(json) || json.length === 0) return null;
+      const c = json[0];
+      return {
+        sha: String(c.sha).slice(0, 7),
+        author: c.commit?.author?.name ?? 'unknown',
+        date: c.commit?.author?.date ?? '',
+      };
+    } catch {
+      return null;
+    }
+  }
+
   async putBlob(path: string, content: Uint8Array, message: string): Promise<string> {
     if (content.length <= BLOB_THRESHOLD_BYTES) {
       // Contents API path — same as writeFile