3 people reported

All time, since Oct 11, including 1 thumbs-up on GitHub.

setImmediate hops stall inside expect().resolves/.rejects with open I/O

“The same code awaited directly runs each hop in well under a millisecond.”

Is this your bug? What gets counted gets fixed. Pile on.

Paste this into your agent. It files your report, with your error and version.

I hit this bug: rapsheet.dev/sheets/bun/issues/11740/file
Follow it to file my report. Show me the text before you send.

No install. No account. Public and anonymous. The link asks your agent for one report, nothing else. What it sends

While a bun:test matcher awaits a pending promise, setImmediate callbacks run only every few hundred milliseconds if any I/O handle is open.

Is this your bug?

Where: bun:test
Versions: 1.4.3
Platforms: macOS
How bad: Breaks a normal workflow.

Not quite your bug?

Resolves/rejects hang on Worker replies2 people
expect resolves/rejects hangs2 people

Original reports2, newest first

Oct 16, 2026bun:test: setImmediate callbacks starved while awaiting expect(promise).resolves/.rejects when any I/O handle is open#45629
Oct 11, 2026expect(promise).resolves/.rejects stalls up to ~1 s per setImmediate hop: the nested event loop blocks in the poll after running immediates#45020

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