feat(FN-3862): add merge attribution changeset

Completes Step 6 of FN-3862 with documentation and delivery, including a changeset for the `@runfusion/fusion` package. Also removes an unused line from the self-healing module.

Fusion-Task-Id: FN-3862

.changeset/FN-3862-merge-attribution.md

@@ -0,0 +1,5 @@
+---
+"@runfusion/fusion": patch
+---
+
+Stop overwriting canonical merge commit SHAs on already-done tasks during self-healing reconciliation. Confirmed `mergeDetails.commitSha` is now preserved as authoritative; rediscovery for unconfirmed done tasks prefers the earliest owned commit so the original merge commit wins over later follow-up commits sharing the same `Fusion-Task-Id` trailer.

packages/engine/src/__tests__/self-healing.test.ts

@@ -56,12 +56,16 @@ vi.mock("../worktree-pool.js", () => ({
   scanOrphanedBranches: vi.fn().mockResolvedValue([]),
 }));
 
-vi.mock("../logger.js", () => ({
+const { selfHealingLoggerMock } = vi.hoisted(() => ({
-  createLogger: vi.fn((_name: string) => ({
+  selfHealingLoggerMock: {
     log: vi.fn(),
     warn: vi.fn(),
     error: vi.fn(),
-  })),
+  },
+}));
+
+vi.mock("../logger.js", () => ({
+  createLogger: vi.fn((_name: string) => selfHealingLoggerMock),
 }));
 
 import { SelfHealingManager } from "../self-healing.js";
@@ -84,11 +88,7 @@ type MockLogger = {
 };
 
 function getSelfHealingLogger(): MockLogger {
-  const idx = mockedCreateLogger.mock.calls.findIndex(([name]) => name === "self-healing");
+  return selfHealingLoggerMock;
-  if (idx === -1) {
-    throw new Error("self-healing logger was not created");
-  }
-  return mockedCreateLogger.mock.results[idx]?.value as MockLogger;
 }
 
 // ── Mock helpers ────────────────────────────────────────────────────
@@ -3286,32 +3286,30 @@ describe("stale triage processing eviction before recovery", () => {
 // ── Maintenance cycle concurrency ──────────────────────────────────
 
 describe("recoverDoneTaskMergeMetadata", () => {
-  it("upgrades done task metadata to an owned landed commit", async () => {
+  it("FN-3862: confirmed task with reachable owned stored SHA preserves canonical commitSha", async () => {
     const store = createMockStore();
     const manager = new SelfHealingManager(store, { rootDir: "/tmp/test-project" });
 
     (store.listTasks as ReturnType<typeof vi.fn>).mockResolvedValue([
       {
-        id: "FN-3469",
+        id: "FN-3862",
         column: "done",
         paused: false,
-        baseCommitSha: "base",
+        mergeDetails: { commitSha: "merge1", mergeConfirmed: true },
-        mergeDetails: { commitSha: "sharedsha", mergeConfirmed: false },
-        modifiedFiles: ["AGENTS.md"],
       },
     ]);
 
     mockedExecSync.mockImplementation((command) => {
       const cmd = String(command);
-      if (cmd.includes("merge-base --is-ancestor sharedsha HEAD")) return "" as any;
+      if (cmd.includes("merge-base --is-ancestor 'merge1' HEAD")) return "" as any;
-      if (cmd.includes("log -1 --format=%H%x1f%s%x1f%b sharedsha")) {
+      if (cmd.includes("log -1 --format=%H%x1f%s%x1f%b 'merge1'")) {
-        return "sharedsha\u001ffix(FN-3468): other\u001fFusion-Task-Id: FN-3468" as any;
+        return "merge1\u001ffix(FN-3862): canonical merge\u001fFusion-Task-Id: FN-3862" as any;
       }
-      if (cmd.includes("Fusion-Task-Id: FN-3469")) {
+      if (cmd.includes("show --shortstat --format= merge1")) {
-        return "a47b1e5\u001ffix(FN-3469): correct lazy-loaded views\n" as any;
+        return "3 files changed, 10 insertions(+), 1 deletions(-)" as any;
       }
-      if (cmd.includes("show --shortstat --format= a47b1e5")) {
+      if (cmd.includes("Fusion-Task-Id: FN-3862")) {
-        return "2 files changed, 84 insertions(+), 2 deletions(-)" as any;
+        return "fix2\u001ffix(FN-3862): follow-up\n" as any;
       }
       return "" as any;
     });
@@ -3319,17 +3317,108 @@ describe("recoverDoneTaskMergeMetadata", () => {
     const repaired = await manager.recoverDoneTaskMergeMetadata();
 
     expect(repaired).toBe(1);
-    expect(store.updateTask).toHaveBeenCalledWith("FN-3469", {
+    expect(store.updateTask).toHaveBeenCalledTimes(1);
+    expect(store.updateTask).toHaveBeenCalledWith("FN-3862", {
       mergeDetails: expect.objectContaining({
-        commitSha: "a47b1e5",
+        commitSha: "merge1",
-        mergeConfirmed: true,
       }),
     });
 
     manager.stop();
   });
 
-  it("clears unowned shared SHA for done task when no owned landed commit exists", async () => {
+  it("FN-3862: confirmed task with unreachable stored SHA is preserved with warning", async () => {
+    const store = createMockStore();
+    const manager = new SelfHealingManager(store, { rootDir: "/tmp/test-project" });
+
+    (store.listTasks as ReturnType<typeof vi.fn>).mockResolvedValue([
+      {
+        id: "FN-3814",
+        column: "done",
+        paused: false,
+        mergeDetails: {
+          commitSha: "gone1234",
+          mergeConfirmed: true,
+          filesChanged: 1,
+          insertions: 1,
+          deletions: 0,
+          mergeCommitMessage: "feat(FN-3814): landed",
+        },
+      },
+    ]);
+
+    mockedExecSync.mockImplementation((command) => {
+      const cmd = String(command);
+      if (cmd.includes("merge-base --is-ancestor gone1234 HEAD")) {
+        const err = new Error("not ancestor");
+        throw err as any;
+      }
+      if (cmd.includes("Fusion-Task-Id: FN-3814")) {
+        return "fix-later\u001ffix(FN-3814): later\n" as any;
+      }
+      return "" as any;
+    });
+
+    const warn = getSelfHealingLogger().warn;
+    warn.mockClear();
+
+    const repaired = await manager.recoverDoneTaskMergeMetadata();
+
+    expect(repaired).toBe(0);
+    expect(store.updateTask).not.toHaveBeenCalled();
+    expect(warn).toHaveBeenCalledWith(expect.stringContaining("gone1234"));
+
+    manager.stop();
+  });
+
+  it("FN-3862: unconfirmed task with multiple owned commits picks earliest via --reverse", async () => {
+    const store = createMockStore();
+    const manager = new SelfHealingManager(store, { rootDir: "/tmp/test-project" });
+
+    (store.listTasks as ReturnType<typeof vi.fn>).mockResolvedValue([
+      {
+        id: "FN-3829",
+        column: "done",
+        paused: false,
+        baseCommitSha: "base",
+        mergeDetails: { commitSha: "old", mergeConfirmed: false },
+      },
+    ]);
+
+    mockedExecSync.mockImplementation((command) => {
+      const cmd = String(command);
+      if (cmd.includes("merge-base --is-ancestor old HEAD")) {
+        throw new Error("not ancestor") as any;
+      }
+      if (cmd.includes("--reverse") && cmd.includes("Fusion-Task-Id: FN-3829")) {
+        return "mergeSha\u001ffix(FN-3829): merge\nfixupSha\u001ffix(FN-3829): follow-up\n" as any;
+      }
+      if (cmd.includes("Fusion-Task-Id: FN-3829")) {
+        return "fixupSha\u001ffix(FN-3829): follow-up\nmergeSha\u001ffix(FN-3829): merge\n" as any;
+      }
+      if (cmd.includes("show --shortstat --format= mergeSha")) {
+        return "2 files changed, 4 insertions(+), 1 deletions(-)" as any;
+      }
+      return "" as any;
+    });
+
+    const repaired = await manager.recoverDoneTaskMergeMetadata();
+
+    expect(repaired).toBe(1);
+    expect(store.updateTask).toHaveBeenCalledWith("FN-3829", {
+      mergeDetails: expect.objectContaining({
+        commitSha: "mergeSha",
+      }),
+    });
+    expect(mockedExecSync).toHaveBeenCalledWith(
+      expect.stringContaining("--reverse"),
+      expect.anything(),
+    );
+
+    manager.stop();
+  });
+
+  it("FN-3862: unconfirmed task with no owned landed commit clears unowned stored SHA", async () => {
     const store = createMockStore();
     const manager = new SelfHealingManager(store, { rootDir: "/tmp/test-project" });
 

packages/engine/src/self-healing.ts

@@ -470,7 +470,10 @@ export class SelfHealingManager {
     return Date.now() - updatedAt >= timeoutMs;
   }
 
-  private async findLandedTaskCommit(task: Task): Promise<LandedTaskCommit | null> {
+  private async findLandedTaskCommit(
+    task: Task,
+    options?: { preferEarliestOwnedCommit?: boolean },
+  ): Promise<LandedTaskCommit | null> {
     // Search strategies, tried in order of reliability:
     //   1. mergeDetails.commitSha — already stored by the merger; verify it's
     //      reachable from HEAD before trusting it.
@@ -517,6 +520,7 @@ export class SelfHealingManager {
         "git log",
         "--format=%H%x1f%s",
         "--max-count=20",
+        ...(options?.preferEarliestOwnedCommit ? ["--reverse"] : []),
         ...(fixedStrings ? ["--fixed-strings"] : ["-E"]),
         `--grep=${grepArg}`,
         shellQuote(range),
@@ -1305,19 +1309,52 @@ export class SelfHealingManager {
       let repaired = 0;
       for (const task of candidates) {
         try {
-          const landed = await this.findLandedTaskCommit(task);
+          const storedSha = task.mergeDetails?.commitSha;
-          if (!landed) {
+          if (!storedSha) continue;
-            if (task.mergeDetails?.mergeConfirmed === false) {
+
-              await this.store.updateTask(task.id, { mergeDetails: undefined });
+          if (task.mergeDetails?.mergeConfirmed === true) {
-              await this.store.logEntry(task.id, "Auto-recovered: cleared unowned done-task mergeDetails commitSha");
+            const landed = await this.findLandedTaskCommit(task);
-              repaired++;
+            if (!landed || landed.sha !== storedSha) {
+              log.warn(
+                `Refusing to overwrite confirmed mergeDetails.commitSha for ${task.id} — stored SHA ${storedSha.slice(0, 8)} no longer reachable; preserving canonical attribution`,
+              );
+              continue;
             }
+
+            const needsMetadataRepair =
+              task.mergeDetails?.filesChanged === undefined ||
+              task.mergeDetails?.insertions === undefined ||
+              task.mergeDetails?.deletions === undefined ||
+              task.mergeDetails?.mergeCommitMessage === undefined;
+
+            if (!needsMetadataRepair) continue;
+
+            await this.store.updateTask(task.id, {
+              mergeDetails: {
+                ...task.mergeDetails,
+                filesChanged: task.mergeDetails?.filesChanged ?? landed.filesChanged,
+                insertions: task.mergeDetails?.insertions ?? landed.insertions,
+                deletions: task.mergeDetails?.deletions ?? landed.deletions,
+                mergeCommitMessage: task.mergeDetails?.mergeCommitMessage ?? landed.subject,
+                mergedAt: task.mergeDetails?.mergedAt ?? new Date().toISOString(),
+                prNumber: task.prInfo?.number,
+              },
+            });
+            await this.store.logEntry(task.id, `Auto-recovered: reconciled done-task mergeDetails to owned commit ${landed.sha.slice(0, 8)}`);
+            repaired++;
+            continue;
+          }
+
+          const landed = await this.findLandedTaskCommit(task, { preferEarliestOwnedCommit: true });
+          if (!landed) {
+            await this.store.updateTask(task.id, { mergeDetails: undefined });
+            await this.store.logEntry(task.id, "Auto-recovered: cleared unowned done-task mergeDetails commitSha");
+            repaired++;
             continue;
           }
 
           const needsRepair =
             task.mergeDetails?.commitSha !== landed.sha ||
-            task.mergeDetails?.mergeConfirmed !== true ||
             task.mergeDetails?.filesChanged === undefined;
 
           if (!needsRepair) continue;