feat(FN-4522): complete Step 1 — fix rename/copy parsing

Fusion-Task-Id: FN-4522
Fusion-Task-Lineage: fbaedf11-6bc6-4c77-91b0-6b1ef606d81f

packages/dashboard/src/__tests__/routes-github.test.ts

@@ -1978,6 +1978,45 @@ describe("GET /tasks/:id/diff", () => {
       expect(res.body.stats).toHaveProperty("filesChanged");
     });
   });
+
+  it("uses destination path for rename entries in active-task name-status parsing", async () => {
+    const root = mkdtempSync(join(tmpdir(), "kb-dashboard-rename-"));
+    try {
+      execFileSync("git", ["init", "--initial-branch=main", root], { stdio: "pipe" });
+      execFileSync("git", ["-C", root, "config", "user.email", "kb-tests@example.com"], { stdio: "pipe" });
+      execFileSync("git", ["-C", root, "config", "user.name", "KB Tests"], { stdio: "pipe" });
+      writeFileSync(join(root, "old.ts"), "export const value = 1;\n");
+      execFileSync("git", ["-C", root, "add", "old.ts"], { stdio: "pipe" });
+      execFileSync("git", ["-C", root, "commit", "-m", "add old"], { stdio: "pipe" });
+      const baseSha = execFileSync("git", ["-C", root, "rev-parse", "HEAD"], { encoding: "utf-8", stdio: "pipe" }).trim();
+      execFileSync("git", ["-C", root, "mv", "old.ts", "new.ts"], { stdio: "pipe" });
+      writeFileSync(join(root, "new.ts"), "export const value = 2;\n");
+
+      const localStore = createMockStore({ getRootDir: vi.fn().mockReturnValue(root) });
+      (localStore.getTask as ReturnType<typeof vi.fn>).mockResolvedValue({
+        ...FAKE_TASK_DETAIL,
+        id: "FN-001",
+        column: "in-progress",
+        branch: "main",
+        worktree: root,
+        baseCommitSha: baseSha,
+      });
+
+      const app = express();
+      app.use(express.json());
+      app.use("/api", createApiRoutes(localStore));
+
+      const res = await GET(app, "/api/tasks/FN-001/diff");
+      expect(res.status).toBe(200);
+      expect(res.body.files.map((file: { path: string }) => file.path)).toContain("new.ts");
+      expect(res.body.files.map((file: { path: string }) => file.path)).not.toContain("old.ts");
+      expect(res.body.stats.filesChanged).toBe(1);
+      expect(Number.isInteger(res.body.stats.additions)).toBe(true);
+      expect(Number.isInteger(res.body.stats.deletions)).toBe(true);
+    } finally {
+      rmSync(root, { recursive: true, force: true });
+    }
+  });
 });
 
 describe("GET /tasks/:id/file-diffs", () => {

packages/dashboard/src/routes/register-session-diff-routes.ts

@@ -263,17 +263,31 @@ function parseStatusCode(statusCode: string): DoneTaskFileStatus {
   return "modified";
 }
 
+/**
+ * Parse a single `git diff --name-status` line.
+ *
+ * Rename/copy entries are detected by `R*`/`C*` status prefixes. Their
+ * destination path is `parts[2]` in normal output, with a defensive `parts[3]`
+ * fallback for variants that split score fields across extra tab columns.
+ */
+function parseNameStatusLine(line: string): { statusCode: string; path: string; oldPath?: string } | null {
+  const parts = line.split("\t");
+  const statusCode = parts[0] ?? "M";
+  const isRenameLike = statusCode.startsWith("R") || statusCode.startsWith("C");
+  const oldPath = isRenameLike ? (parts[1] ?? "") : undefined;
+  const path = isRenameLike ? (parts.length > 3 ? (parts[3] ?? "") : (parts[2] ?? "")) : (parts[1] ?? "");
+  if (!path) return null;
+  return oldPath ? { statusCode, path, oldPath } : { statusCode, path };
+}
+
 async function collectDoneRangeFiles(range: string, rootDir: string): Promise<AggregatedDoneTaskFile[]> {
   const nameStatus = (await runGitCommand(["diff", "--name-status", "-M", range], rootDir, 10000)).trim();
   const files: AggregatedDoneTaskFile[] = [];
 
   for (const line of nameStatus.split("\n").filter(Boolean)) {
-    const parts = line.split("\t");
+    const parsed = parseNameStatusLine(line);
-    const statusCode = parts[0] ?? "M";
+    if (!parsed) continue;
-    const isRenameLike = statusCode.startsWith("R") || statusCode.startsWith("C");
+    const { statusCode, path: filePath, oldPath } = parsed;
-    const oldPath = isRenameLike ? (parts[1] ?? "") : undefined;
-    const filePath = isRenameLike ? (parts[2] ?? parts[1] ?? "") : (parts[1] ?? "");
-    if (!filePath) continue;
 
     let patch = "";
     try {
@@ -628,8 +642,9 @@ export function registerSessionDiffRoutes(router: Router, deps: SessionDiffRoute
         try {
           const committedOutput = (await runGitCommand(["diff", "--name-status", `${diffBase}..HEAD`], cwd, 10000)).trim();
           for (const line of committedOutput.split("\n").filter(Boolean)) {
-            const parts = line.split("\t");
+            const parsed = parseNameStatusLine(line);
-            fileMap.set(parts[1] ?? "", parts[0] ?? "M");
+            if (!parsed) continue;
+            fileMap.set(parsed.path, parsed.statusCode);
           }
         } catch {
           // committed diff failed
@@ -639,11 +654,9 @@ export function registerSessionDiffRoutes(router: Router, deps: SessionDiffRoute
       try {
         const stagedOutput = (await runGitCommand(["diff", "--cached", "--name-status"], cwd, 10000)).trim();
         for (const line of stagedOutput.split("\n").filter(Boolean)) {
-          const parts = line.split("\t");
+          const parsed = parseNameStatusLine(line);
-          const filePath = parts[1] ?? "";
+          if (!parsed || fileMap.has(parsed.path)) continue;
-          if (filePath && !fileMap.has(filePath)) {
+          fileMap.set(parsed.path, parsed.statusCode);
-            fileMap.set(filePath, parts[0] ?? "M");
-          }
         }
       } catch {
         // staged diff failed
@@ -652,11 +665,9 @@ export function registerSessionDiffRoutes(router: Router, deps: SessionDiffRoute
       try {
         const workingTreeOutput = (await runGitCommand(["diff", "--name-status"], cwd, 10000)).trim();
         for (const line of workingTreeOutput.split("\n").filter(Boolean)) {
-          const parts = line.split("\t");
+          const parsed = parseNameStatusLine(line);
-          const filePath = parts[1] ?? "";
+          if (!parsed || fileMap.has(parsed.path)) continue;
-          if (filePath && !fileMap.has(filePath)) {
+          fileMap.set(parsed.path, parsed.statusCode);
-            fileMap.set(filePath, parts[0] ?? "M");
-          }
         }
       } catch {
         // working tree diff failed