fix(test): fix race condition in next-pages HMR test

[robobun]

Summary

• Fixed intermittent timeout in test/integration/next-pages/test/dev-server.test.ts
• The HMR test was failing because the console message listener was being set up AFTER the file copy that triggers HMR
• In fast environments, the HMR cycle could complete before the listener was attached, causing the test to miss the "counter b loaded" message

Test plan

• Code compiles correctly
• Test should pass consistently on CI (cannot test locally on linux arm64 due to puppeteer limitations)

Fixes #11255

🤖 Generated with Claude Code

[robobun]

^{Updated 8:12 PM PT - Jan 20th, 2026}

❌ Your commit 9f3bb999 has 3 failures in Build #35465 (All Failures):

• test/cli/hot/watch-many-dirs.test.ts - pid 3482 segmentation fault on 🐧 3.22 x64-baseline
• test/regression/issue/11297/11297.test.ts - 1 failing on 🪟 2019 x64-baseline
• test/integration/next-pages/test/dev-server.test.ts - 1 failing on 🍎 13 aarch64

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bunx bun-pr 26311

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[coderabbitai]

Walkthrough

Added persistent console buffering and an index-aware waitForConsoleMessage to the dev-server Puppeteer test; navigations and reloads now use explicit load semantics and console-message index markers (initial load, reload, HMR) to avoid race conditions and sequence test steps. (50 words)

Changes

Cohort / File(s)

Summary

Dev-server Puppeteer test test/integration/next-pages/test/dev-server-puppeteer.ts

Added consoleMessages buffer and a persistent p.on("console", …) listener; implemented waitForConsoleMessage(p, regex, startIndex?) that checks buffered messages and returns the next search index; switched navigations (page.goto, page.reload) to waitUntil: "load" / networkidle0; introduced index markers (afterInitialLoad, afterReload) and updated HMR/file-swap waits to use index-aware synchronization and visibility checks.

🚥 Pre-merge checks | ✅ 4

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and concisely describes the main change: fixing a race condition in the next-pages HMR test.
Description check	✅ Passed	The description covers both required template sections with clear details about the race condition root cause and test verification status.
Linked Issues check	✅ Passed	The code changes implement the core fix for issue #11255 by attaching the console listener before the file copy and using buffered message tracking to prevent race conditions.
Out of Scope Changes check	✅ Passed	All changes are focused on fixing the HMR test race condition in dev-server-puppeteer.ts and are directly related to the linked issue requirements.

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[coderabbitai]

Actionable comments posted: 0

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (1)

test/integration/next-pages/test/dev-server-puppeteer.ts (1)

66-85: Reload wait can resolve before the reload happens.

Both initial_load_promise and reload_promise listen for /counter a/ and are attached at the same time (lines 82–83), so the first match resolves both. This makes await reload_promise at line 117 effectively a no-op, reintroducing the race condition the early attachment was meant to prevent. Wait for the second match (or otherwise distinguish the reload signal) while still attaching the listener early.

🛠️ Suggested fix (wait for Nth match)

-  function waitForConsoleMessage(page: Page, regex: RegExp) {
+  function waitForConsoleMessage(page: Page, regex: RegExp, matchIndex = 1) {
     const { resolve, promise } = Promise.withResolvers<void>();
+    let matches = 0;
     function onMessage(msg: ConsoleMessage) {
       const text = msg.text();
       if (regex.test(text)) {
-        page.off("console", onMessage);
-        resolve();
+        if (++matches >= matchIndex) {
+          page.off("console", onMessage);
+          resolve();
+        }
       }
     }
     page.on("console", onMessage);
     return promise;
   }
@@
-  const initial_load_promise = waitForConsoleMessage(p, /counter a/);
-  const reload_promise = waitForConsoleMessage(p, /counter a/);
+  const initial_load_promise = waitForConsoleMessage(p, /counter a/, 1);
+  const reload_promise = waitForConsoleMessage(p, /counter a/, 2);

[robobun]

CI build failed due to infrastructure issue (Buildkite API returning malformed JSON in SetupBuildkite.cmake). Tests didn't run. Will need a rebuild.

[coderabbitai]

Actionable comments posted: 1

🤖 Fix all issues with AI agents

In `@test/integration/next-pages/test/dev-server-puppeteer.ts`:
- Around line 74-93: The waitForConsoleMessage function has a race between
checking consoleMessages and attaching the temporary listener; fix it by first
attaching the onMessage listener to page, then re-scan the consoleMessages
buffer (consoleMessages) for a match and if found remove the listener and
resolve immediately, otherwise keep the listener active and return the promise
from Promise.withResolvers; update references in waitForConsoleMessage and
ensure the onMessage handler removes itself via page.off("console", onMessage)
when resolving so you don't leak listeners.