fix(FN-4526): finalize stale merge stats repairs and changeset

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

.changeset/fn-4526-recompute-merge-stats-after-push.md

@@ -0,0 +1,5 @@
+---
+"@runfusion/fusion": patch
+---
+
+Fix stale "files changed / insertions / deletions" on done tasks when `pushAfterMerge` is enabled. After `pushToRemoteAfterMerge` rebases HEAD, the merger now re-reads `git show --shortstat <postPushSha>` and rewrites `mergeDetails.filesChanged/insertions/deletions` alongside the refreshed `commitSha` (previously only the SHA was updated, leaving pre-rebase squash stats attached to the post-rebase commit). The `recoverDoneTaskMergeMetadata` self-healing pass also now detects and repairs stored stats that disagree with the live commit at the stored SHA, both at startup and during periodic maintenance.

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

@@ -110,7 +110,7 @@ describeIfGit("SelfHealingManager recoverDoneTaskMergeMetadata stale stats", ()
   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 task = makeTask("FN-4526-STATS", repo, sha, expected);
     const tasks = new Map([[task.id, task]]);
     const store = createStore(tasks);
     const manager = new SelfHealingManager(store, { rootDir: repo, getExecutingTaskIds: () => new Set() });
@@ -119,4 +119,22 @@ describeIfGit("SelfHealingManager recoverDoneTaskMergeMetadata stale stats", ()
 
     expect((store.updateTask as any).mock.calls).toHaveLength(0);
   });
+
+  it("repairs stale stats in unconfirmed branch when SHA matches landed commit", async () => {
+    const { repo, sha } = setupRepo();
+    const expected = parseShortstat(git(repo, `git show --shortstat --format= ${sha}`));
+    const task = makeTask("FN-4526-STATS", repo, sha, { filesChanged: 777, insertions: 888, deletions: 999, mergeConfirmed: false });
+    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(repaired.mergeDetails?.mergeConfirmed).toBe(true);
+  });
 });

packages/engine/src/self-healing.ts

@@ -2550,7 +2550,12 @@ export class SelfHealingManager {
         cwd: this.options.rootDir,
         maxBuffer: 1024 * 1024,
       });
-      return parseShortstat(stats.stdout);
+      const parsed = parseShortstat(stats.stdout);
+      return {
+        filesChanged: parsed.filesChanged ?? 0,
+        insertions: parsed.insertions ?? 0,
+        deletions: parsed.deletions ?? 0,
+      };
     } catch {
       return null;
     }
@@ -2630,15 +2635,21 @@ export class SelfHealingManager {
             continue;
           }
 
+          const landedStats = {
+            filesChanged: landed.filesChanged ?? 0,
+            insertions: landed.insertions ?? 0,
+            deletions: landed.deletions ?? 0,
+          };
+
           const needsRepair =
             task.mergeDetails?.commitSha !== landed.sha ||
             task.mergeDetails?.filesChanged === undefined ||
             task.mergeDetails?.insertions === undefined ||
             task.mergeDetails?.deletions === undefined || (
               task.mergeDetails?.commitSha === landed.sha && (
-                task.mergeDetails?.filesChanged !== landed.filesChanged ||
+                task.mergeDetails?.filesChanged !== landedStats.filesChanged ||
-                task.mergeDetails?.insertions !== landed.insertions ||
+                task.mergeDetails?.insertions !== landedStats.insertions ||
-                task.mergeDetails?.deletions !== landed.deletions
+                task.mergeDetails?.deletions !== landedStats.deletions
               )
             );
 
@@ -2648,9 +2659,9 @@ export class SelfHealingManager {
             mergeDetails: {
               ...task.mergeDetails,
               commitSha: landed.sha,
-              filesChanged: landed.filesChanged,
+              filesChanged: landedStats.filesChanged,
-              insertions: landed.insertions,
+              insertions: landedStats.insertions,
-              deletions: landed.deletions,
+              deletions: landedStats.deletions,
               mergeCommitMessage: landed.subject,
               mergedAt: task.mergeDetails?.mergedAt ?? new Date().toISOString(),
               mergeConfirmed: true,