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Node/libuv assertion error on Windows self-hosted GitHub Actions runner #686
Description
I'm using a self-hosted GitHub Actions runner on Windows and I'm seeing the following error when using setup-uv@v7 (I've bisected the appearance of the error to v7.0.0):
Assertion failed: !(handle->flags & UV_HANDLE_CLOSING), file src\win\async.c, line 76
MRE
- name: Setup uv
uses: astral-sh/setup-uv@v7
Run astral-sh/setup-uv@v7
(node:21512) [DEP0040] DeprecationWarning: The `punycode` module is deprecated. Please use a userland alternative instead.
(Use `node --trace-deprecation ...` to show where the warning was created)
Trying to find version for uv in: C:\Users\User\actions-runner\_work\my-project\my-project\uv.toml
Could not find file: C:\Users\User\actions-runner\_work\my-project\my-project\uv.toml
Trying to find version for uv in: C:\Users\User\actions-runner\_work\my-project\my-project\pyproject.toml
Could not determine uv version from uv.toml or pyproject.toml. Falling back to latest.
Getting latest version from GitHub API...
Found uv in tool-cache for 0.9.10
Set UV_TOOL_BIN_DIR to C:\Users\User\actions-runner\_work\_temp\uv-tool-bin-dir
Added C:\Users\User\actions-runner\_work\_temp\uv-tool-bin-dir to the path
Added C:\Users\User\actions-runner\_work\_tool\uv\0.9.10\x86_64 to the path
Set UV_TOOL_DIR to C:\Users\User\actions-runner\_work\_temp\uv-tool-dir
Set UV_PYTHON_INSTALL_DIR to C:\Users\User\AppData\Roaming\uv\python
Added C:\Users\User\AppData\Roaming\uv\python to the path
Successfully installed uv version 0.9.10
Assertion failed: !(handle->flags & UV_HANDLE_CLOSING), file src\win\async.c, line 76
As you can see, uv installs successfully, but then the workflow aborts.
This appears to match a known upstream Node issue on Windows? But I'm not sure exactly what's going on here.
Runner info
- GitHub Actions runner v2.329.0 (https://github.com/actions/runner/releases/tag/v2.329.0)
Current runner version: '2.329.0'
node -v
v22.17.1
Activity
eifinger commentedon Nov 20, 2025
Is this 100% reproducible?
If yes, can you please test with the branch
fix-libuv-error?my1e5 commentedon Nov 20, 2025
@eifinger Yes, 100% reproducible. Also, I noticed another project reported seeing the same error yesterday (see ansys/pyaedt#6897 (comment))
And good news,
fix-libuv-erroris giving no error 😃 Thanks!Wait 50ms before exit to fix libuv bug (#689)
da1910 commentedon May 6, 2026
We are seeing this issue recur on self-hosted windows server 2022 runners, using the pinned action version
cec208311dfd045dd5311c1add060b2062131d57. The action successfully installs uv, but then fails as before:We're using github actions runner version
2.334.0increase libuv-workaround timeout to 100ms (#880)
increase libuv-workaround timeout to 100ms (#880)
increase libuv-workaround timeout to 100ms (#880)
[CI] Cross-platform — Part 3: Windows workflow (#5700)