fix(sync): paginate compare and resolve real head SHA

2026-07-11 13:44:10 -04:00
parent c8200a6747
commit 4684617fed
3 changed files with 128 additions and 12 deletions
@@ -1,7 +1,10 @@
 import type { Octokit } from '@octokit/rest';
 import { describe, expect, it, vi } from 'vitest';

-import { resolveBranchHead } from '../../convex/githubClient';
+import {
+  compareAcrossForkNetwork,
+  resolveBranchHead,
+} from '../../convex/githubClient';

 describe('resolveBranchHead', () => {
  it('returns the branch tip sha from the branch ref', async () => {
@@ -22,3 +25,84 @@ describe('resolveBranchHead', () => {
    });
  });
 });
+
+const makeCommit = (sha: string) => ({
+  sha,
+  commit: {
+    message: `commit ${sha}`,
+    author: { name: 'Dev', email: 'dev@example.com', date: '2026-01-01T00:00:00Z' },
+    committer: { name: 'Dev', email: 'dev@example.com', date: '2026-01-01T00:00:00Z' },
+  },
+  author: { login: 'dev' },
+  html_url: `https://github.com/o/r/commit/${sha}`,
+});
+
+describe('compareAcrossForkNetwork', () => {
+  it('paginates the compare and takes headSha from the branch tip, not the last commit', async () => {
+    const page1 = Array.from({ length: 100 }, (_, i) => makeCommit(`c${i}`));
+    // Last commit in the collected list is a DIFFERENT sha than the branch tip.
+    const page2 = Array.from({ length: 50 }, (_, i) =>
+      makeCommit(i === 49 ? 'LAST_COMMIT_NOT_TIP' : `c${100 + i}`),
+    );
+
+    const compareCommitsWithBasehead = vi.fn(
+      async ({ page }: { page?: number }) => {
+        const commits = page === 2 ? page2 : page1;
+        return {
+          data: {
+            total_commits: 150,
+            ahead_by: 150,
+            merge_base_commit: { sha: 'MERGE_BASE' },
+            base_commit: { sha: 'BASE' },
+            html_url: 'https://github.com/o/r/compare/base...head',
+            commits,
+          },
+        };
+      },
+    );
+    const getBranch = vi.fn(async () => ({
+      data: { commit: { sha: 'TIP' } },
+    }));
+    const octokit = {
+      rest: { repos: { compareCommitsWithBasehead, getBranch } },
+    } as unknown as Octokit;
+
+    const result = await compareAcrossForkNetwork(octokit, {
+      owner: 'up',
+      repo: 'upstream-repo',
+      baseOwner: 'fork',
+      baseBranch: 'main',
+      headOwner: 'up',
+      headRepo: 'upstream-repo',
+      headBranch: 'main',
+    });
+
+    // Core bug: head is the branch tip, NOT the last commit in the compare list.
+    expect(result.headSha).toBe('TIP');
+    expect(result.commits[result.commits.length - 1]?.sha).toBe(
+      'LAST_COMMIT_NOT_TIP',
+    );
+    expect(result.headSha).not.toBe('LAST_COMMIT_NOT_TIP');
+
+    // ahead_by / merge base / base come from the first compare page.
+    expect(result.aheadBy).toBe(150);
+    expect(result.mergeBaseSha).toBe('MERGE_BASE');
+    expect(result.baseSha).toBe('BASE');
+
+    // All commits collected across both pages.
+    expect(result.commits).toHaveLength(150);
+
+    // Pagination is bounded and the tip is resolved via a single branch ref call.
+    expect(getBranch).toHaveBeenCalledTimes(1);
+    expect(getBranch).toHaveBeenCalledWith({
+      owner: 'up',
+      repo: 'upstream-repo',
+      branch: 'main',
+    });
+    expect(compareCommitsWithBasehead).toHaveBeenCalledTimes(2);
+    expect(compareCommitsWithBasehead.mock.calls[0]?.[0]).toMatchObject({
+      per_page: 100,
+      page: 1,
+    });
+  });
+});