feat(FN-4288): complete Step 2 — add stall log entry locator

Fusion-Task-Id: FN-4288
Fusion-Task-Lineage: 09c6efc0-ea0b-443a-ab45-a89188fcf888

packages/dashboard/app/utils/__tests__/findInReviewStallLogEntry.test.ts

@@ -0,0 +1,61 @@
+import type { TaskLogEntry } from "@fusion/core";
+import { describe, expect, it } from "vitest";
+
+import { findInReviewStallLogEntry } from "../findInReviewStallLogEntry";
+
+function makeEntry(action: string, timestamp = "2026-05-13T00:00:00.000Z"): TaskLogEntry {
+  return { action, timestamp };
+}
+
+describe("findInReviewStallLogEntry", () => {
+  it("returns undefined for empty logs", () => {
+    expect(findInReviewStallLogEntry({ log: [] }, "merge-blocker")).toBeUndefined();
+  });
+
+  it("returns undefined when no entries match", () => {
+    expect(
+      findInReviewStallLogEntry(
+        { log: [makeEntry("Something else happened"), makeEntry("Merge retries started")] },
+        "merge-blocker",
+      ),
+    ).toBeUndefined();
+  });
+
+  it("returns single match as newest entry with reversedIndex 0", () => {
+    const entry = makeEntry("In-review stall surfaced [merge-blocker]: blocked");
+    const result = findInReviewStallLogEntry({ log: [entry] }, "merge-blocker");
+
+    expect(result?.entry).toBe(entry);
+    expect(result?.reversedIndex).toBe(0);
+    expect(result?.code).toBe("merge-blocker");
+  });
+
+  it("returns the most recent matching code", () => {
+    const older = makeEntry("In-review stall surfaced [merge-blocker]: older");
+    const otherCode = makeEntry("In-review stall surfaced [merge-retries-exhausted]: other");
+    const newest = makeEntry("In-review stall surfaced [merge-blocker]: newest");
+
+    const result = findInReviewStallLogEntry({ log: [older, otherCode, newest] }, "merge-blocker");
+
+    expect(result?.entry.action).toContain("newest");
+    expect(result?.reversedIndex).toBe(0);
+  });
+
+  it("returns undefined when code does not match", () => {
+    expect(
+      findInReviewStallLogEntry(
+        { log: [makeEntry("In-review stall surfaced [merge-retries-exhausted]: exhausted")] },
+        "merge-blocker",
+      ),
+    ).toBeUndefined();
+  });
+
+  it("is case-sensitive for the canonical prefix", () => {
+    expect(
+      findInReviewStallLogEntry(
+        { log: [makeEntry("in-review stall surfaced [merge-blocker]: lower")] },
+        "merge-blocker",
+      ),
+    ).toBeUndefined();
+  });
+});

packages/dashboard/app/utils/findInReviewStallLogEntry.ts

@@ -0,0 +1,31 @@
+import type { InReviewStallCode, Task, TaskLogEntry } from "@fusion/core";
+
+export const IN_REVIEW_STALL_LOG_PREFIX = "In-review stall surfaced [";
+export const IN_REVIEW_STALL_LOG_REGEX = /^In-review stall surfaced \[([^\]]+)\]/;
+
+export interface InReviewStallLogMatch {
+  entry: TaskLogEntry;
+  reversedIndex: number;
+  code: InReviewStallCode;
+}
+
+export function findInReviewStallLogEntry(
+  task: Pick<Task, "log">,
+  code: InReviewStallCode,
+): InReviewStallLogMatch | undefined {
+  if (!task.log?.length) {
+    return undefined;
+  }
+
+  const reversed = [...task.log].reverse();
+  for (const [reversedIndex, entry] of reversed.entries()) {
+    const match = entry.action.match(IN_REVIEW_STALL_LOG_REGEX);
+    if (!match || match[1] !== code) {
+      continue;
+    }
+
+    return { entry, reversedIndex, code };
+  }
+
+  return undefined;
+}