feat(FN-4526): complete Step 2 — repair stale done-task merge stats

Fusion-Task-Id: FN-4526
Fusion-Task-Lineage: 38dc93d6-3e56-4e22-aaaa-d09b2eed43e5

packages/engine/src/__tests__/self-healing-stale-merge-stats.real-git.test.ts

@@ -0,0 +1,122 @@
+import { afterEach, describe, expect, it, vi } from "vitest";
+import { execSync, spawnSync } from "node:child_process";
+import { mkdtempSync, rmSync, writeFileSync } from "node:fs";
+import os from "node:os";
+import path from "node:path";
+import { EventEmitter } from "node:events";
+import type { Settings, Task, TaskStore } from "@fusion/core";
+import { SelfHealingManager } from "../self-healing.js";
+
+const hasGit = spawnSync("git", ["--version"], { stdio: "pipe" }).status === 0;
+const describeIfGit = hasGit ? describe : describe.skip;
+
+function git(repo: string, command: string): string {
+  return execSync(command, { cwd: repo, encoding: "utf-8", stdio: ["pipe", "pipe", "pipe"] }).trim();
+}
+
+function parseShortstat(output: string): { filesChanged: number; insertions: number; deletions: number } {
+  const normalized = output.trim().replace(/\n/g, " ");
+  return {
+    filesChanged: Number.parseInt(normalized.match(/(\d+) files? changed/)?.[1] ?? "0", 10),
+    insertions: Number.parseInt(normalized.match(/(\d+) insertions?\(\+\)/)?.[1] ?? "0", 10),
+    deletions: Number.parseInt(normalized.match(/(\d+) deletions?\(-\)/)?.[1] ?? "0", 10),
+  };
+}
+
+function makeTask(id: string, repo: string, sha: string, mergeDetails: Task["mergeDetails"]): Task {
+  return {
+    id,
+    title: id,
+    description: id,
+    column: "done",
+    dependencies: [],
+    steps: [],
+    currentStep: 0,
+    log: [],
+    createdAt: new Date().toISOString(),
+    updatedAt: new Date().toISOString(),
+    baseBranch: "main",
+    worktree: repo,
+    mergeDetails: { commitSha: sha, mergeConfirmed: true, mergeCommitMessage: "msg", ...mergeDetails },
+  } as Task;
+}
+
+function createStore(tasks: Map<string, Task>): TaskStore & EventEmitter {
+  const emitter = new EventEmitter();
+  const settings = { globalPause: false, enginePaused: false, maintenanceIntervalMs: 0, taskStuckTimeoutMs: 60_000, autoMerge: false } as Settings;
+  return Object.assign(emitter, {
+    getSettings: vi.fn(async () => settings),
+    listTasks: vi.fn(async ({ column }: { column?: string } = {}) => [...tasks.values()].filter((t) => !column || t.column === column)),
+    getTask: vi.fn(async (id: string) => tasks.get(id)),
+    updateTask: vi.fn(async (id: string, updates: Partial<Task>) => {
+      const cur = tasks.get(id)!;
+      const next = { ...cur, ...updates, mergeDetails: updates.mergeDetails ?? cur.mergeDetails, updatedAt: new Date().toISOString() } as Task;
+      tasks.set(id, next);
+      return next;
+    }),
+    logEntry: vi.fn(async (id: string, message: string) => {
+      const cur = tasks.get(id)!;
+      tasks.set(id, { ...cur, log: [...(cur.log ?? []), { timestamp: new Date().toISOString(), action: message }] as any });
+    }),
+    moveTask: vi.fn(),
+    walCheckpoint: vi.fn(() => ({ busy: 0, log: 0, checkpointed: 0 })),
+    clearStaleExecutionStartBranchReferences: vi.fn(() => []),
+    updateSettings: vi.fn(),
+    mergeTask: vi.fn(),
+    getRootDir: vi.fn(() => ""),
+    recordRunAuditEvent: vi.fn(),
+  }) as unknown as TaskStore & EventEmitter;
+}
+
+describeIfGit("SelfHealingManager recoverDoneTaskMergeMetadata stale stats", () => {
+  const repos: string[] = [];
+  afterEach(() => {
+    for (const repo of repos.splice(0)) rmSync(repo, { recursive: true, force: true });
+  });
+
+  function setupRepo() {
+    const repo = mkdtempSync(path.join(os.tmpdir(), "fn-4526-"));
+    repos.push(repo);
+    git(repo, "git init -b main");
+    git(repo, 'git config user.email "test@example.com"');
+    git(repo, 'git config user.name "Test"');
+    writeFileSync(path.join(repo, "a.ts"), "const a = 1;\n", "utf-8");
+    writeFileSync(path.join(repo, "b.ts"), "const b = 1;\n", "utf-8");
+    git(repo, "git add a.ts b.ts && git commit -m 'init'");
+    writeFileSync(path.join(repo, "a.ts"), "const a = 2;\nconst c = 3;\n", "utf-8");
+    writeFileSync(path.join(repo, "b.ts"), "const b = 2;\n", "utf-8");
+    git(repo, "git add a.ts b.ts && git commit -m 'landed' -m 'Fusion-Task-Id: FN-4526-STATS'");
+    return { repo, sha: git(repo, "git rev-parse HEAD") };
+  }
+
+  it("repairs stale confirmed stats from live shortstat without changing SHA", async () => {
+    const { repo, sha } = setupRepo();
+    const expected = parseShortstat(git(repo, `git show --shortstat --format= ${sha}`));
+    const task = makeTask("FN-4526-STATS", repo, sha, { filesChanged: 99, insertions: 999, deletions: 999 });
+    const tasks = new Map([[task.id, task]]);
+    const store = createStore(tasks);
+    const manager = new SelfHealingManager(store, { rootDir: repo, getExecutingTaskIds: () => new Set() });
+
+    await manager.recoverDoneTaskMergeMetadata();
+
+    const repaired = tasks.get(task.id)!;
+    expect(repaired.mergeDetails?.commitSha).toBe(sha);
+    expect(repaired.mergeDetails?.filesChanged).toBe(expected.filesChanged);
+    expect(repaired.mergeDetails?.insertions).toBe(expected.insertions);
+    expect(repaired.mergeDetails?.deletions).toBe(expected.deletions);
+    expect((store.logEntry as any).mock.calls.some((call: any[]) => String(call[1]).includes("stale mergeDetails stats repaired"))).toBe(true);
+  });
+
+  it("does not rewrite when stats are already correct", async () => {
+    const { repo, sha } = setupRepo();
+    const expected = parseShortstat(git(repo, `git show --shortstat --format= ${sha}`));
+    const task = makeTask("FN-4526-OK", repo, sha, expected);
+    const tasks = new Map([[task.id, task]]);
+    const store = createStore(tasks);
+    const manager = new SelfHealingManager(store, { rootDir: repo, getExecutingTaskIds: () => new Set() });
+
+    await manager.recoverDoneTaskMergeMetadata();
+
+    expect((store.updateTask as any).mock.calls).toHaveLength(0);
+  });
+});