feat: implement fail-fast monitoring to stop as soon as error/traceback is detected

__tests__/monitor.test.js

@@ -455,4 +455,31 @@ describe("monitorConsole", () => {
     );
     expect(api.socket.disconnect).toHaveBeenCalledTimes(1);
   });
+
+  it("exits early if a traceback occurs and onTraceback='fail'", async () => {
+    // startTick=100, monitor=10 ticks.
+    // If it didn't exit early, it would call api.time() many times.
+    const api = buildMockApi({
+      ticks: [100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110],
+    });
+
+    // Fire a traceback event after the first poll
+    setTimeout(() => {
+      api._fireConsole({
+        messages: { log: [], results: [] },
+        error:
+          "TypeError: fail-fast test\n    at Object.<anonymous> (main:1:1)",
+      });
+    }, 100);
+
+    const result = await monitorConsole(api, {
+      ...BASE_OPTS,
+      monitor: 10,
+      onTraceback: "fail",
+    });
+
+    expect(result.sawTraceback).toBe(true);
+    // We expect it to have called api.time fewer than 10 times (excluding the startTick call)
+    expect(api.time.mock.calls.length).toBeLessThan(10);
+  });
 });

monitor.js

@@ -224,9 +224,10 @@ export async function pollUntilDone(
   shard,
   intervalMs,
   onProgress,
+  shouldStop = () => false,
 ) {
   let elapsed = 0;
-  while (elapsed < targetTicks) {
+  while (elapsed < targetTicks && !shouldStop()) {
     await sleep(intervalMs);
     const { time } = await api.time(shard);
     elapsed = time - startTick;
@@ -332,6 +333,13 @@ export async function monitorConsole(api, opts) {
           lastProgressTick = elapsed;
         }
       },
+      () => {
+        // Fail-fast logic: stop monitoring if any 'fail' action is triggered
+        if (opts.onTraceback === "fail" && state.sawTraceback) return true;
+        if (opts.onErrorLog === "fail" && state.sawErrorLog) return true;
+        if (opts.onWarningLog === "fail" && state.sawWarningLog) return true;
+        return false;
+      },
     );
   } finally {
     // ── Step 5: always disconnect cleanly ────────────────────────────────

scratch/test_glob.js

@@ -0,0 +1,29 @@
+import { glob } from "glob";
+import path from "path";
+import os from "os";
+import fs from "fs";
+
+async function test() {
+  const tempDir = await fs.promises.mkdtemp(
+    path.join(os.tmpdir(), "glob-test-"),
+  );
+  const file = path.join(tempDir, "test.js");
+  await fs.promises.writeFile(file, "test");
+
+  const pattern = "*.js";
+  const globPattern = path.join(tempDir, pattern);
+  console.log("globPattern:", globPattern);
+
+  const files = await glob(globPattern);
+  console.log("found files:", files);
+
+  // Fix for windows
+  const fixedPattern = globPattern.replace(/\\/g, "/");
+  console.log("fixedPattern:", fixedPattern);
+  const fixedFiles = await glob(fixedPattern);
+  console.log("found fixed files:", fixedFiles);
+
+  await fs.promises.rm(tempDir, { recursive: true, force: true });
+}
+
+test();