test(server): exclude filesystem startup from config responsiveness (#8296)

* test(server): diagnose recurring config responsiveness failure

* test(server): compare profiled and plain config reads on Windows

* test(server): correlate config profiles with long callbacks

* test(server): probe config timing under CPU contention

* test(server): exclude filesystem pool startup from config budget

* test(terminal): finish output before comparing replay captures

A marker can arrive before its trailing newline. Comparing captures taken on either side of that output compares different terminal states. Split that output deliberately and wait for its parsed completion before capturing the expected replay.

---------

Co-authored-by: paseo-bot[bot] <266920839+paseo-bot[bot]@users.noreply.github.com>

packages/server/src/terminal/worker-terminal-manager.test.ts

@@ -1742,6 +1742,7 @@ it.skipIf(isPlatform("win32"))(
 
 it("replays bounded ANSI chunks independently of live output and reconstructs the revision cut", async () => {
   const cwd = createTemporaryHome();
+  const finishBefore = join(cwd, "finish-before");
   manager = await startRealWorkerManager();
   const session = trackTerminal(
     await manager.createTerminal({
@@ -1751,7 +1752,15 @@ it("replays bounded ANSI chunks independently of live output and reconstructs th
       cols: 120,
       ...nodeTerminalCommand(`
       for (let i = 0; i < 800; i++) process.stdout.write("\\x1b[31m" + String(i).padStart(4, "0") + ":" + "x".repeat(100) + "\\x1b[0m\\r\\n");
-      require("node:readline").createInterface({ input: process.stdin }).on("line", line => process.stdout.write(line === "before" ? "PRE-CUT\\r\\n" : "LIVE-AFTER-REPLAY\\r\\n"));
+      require("node:readline").createInterface({ input: process.stdin }).on("line", line => {
+        if (line !== "before") { process.stdout.write("LIVE-AFTER-REPLAY\\r\\n"); return; }
+        process.stdout.write("PRE-CUT");
+        const finish = setInterval(() => {
+          if (!require("node:fs").existsSync(${JSON.stringify(finishBefore)})) return;
+          clearInterval(finish);
+          process.stdout.write("\\r\\n");
+        }, 5);
+      });
       setInterval(() => {}, 1000);
     `),
     }),
@@ -1775,6 +1784,13 @@ it("replays bounded ANSI chunks independently of live output and reconstructs th
   });
   session.send({ type: "input", data: "before\r" });
   await waitForCondition(() => live.includes("PRE-CUT"), 10000);
+  // A PTY may deliver the marker and its trailing newline separately. Finish
+  // that output before replay, so the two captures must describe the same cut.
+  writeFileSync(finishBefore, "");
+  await waitForCondition(async () => {
+    const { lines } = await manager!.captureTerminal(session.id);
+    return lines.at(-2) === "PRE-CUT" && lines.at(-1) === "";
+  }, 10000);
   const expected = await manager.captureTerminal(session.id);
   const metadata = await manager.replayTerminal(session.id, undefined, (event) => {
     events.push(event.type);

packages/server/src/utils/test-fixtures/config-responsiveness.ts

@@ -1,4 +1,5 @@
 import { createHook, executionAsyncResource } from "node:async_hooks";
+import { stat } from "node:fs/promises";
 import { MessagePort } from "node:worker_threads";
 import assert from "node:assert/strict";
 import { setImmediate as nextTurn } from "node:timers/promises";
@@ -10,6 +11,11 @@ import { readPaseoConfigForEdit } from "../paseo-config-file.js";
 // Read the real file once, without warming the config snapshot or schema.
 const directory = process.argv[2];
 assert.ok(directory, "Config directory is required");
+// The daemon has already used asynchronous filesystem APIs before reading a
+// project config. Start libuv's filesystem worker pool outside the measurement:
+// its first submission synchronously creates workers in a fresh Node process.
+// Stat the probe itself so the config, snapshot and schemas remain cold.
+await stat(process.argv[1]);
 await nextTurn();
 let workerMessages = 0;
 const activity = createHook({