uv >=4.8 cache error output

[pmbarrett314]

UV 4.8 and above is outputting an error that is breaking tests that expect specific console output when caching is enabled. 4.7 works fine.

The error is:
error: Failed to build: curses-menu @ file:///home/runner/work/curses-menu/curses-menu Caused by: Failed to deserialize cache entry Caused by: wrong msgpack marker FixArray(2)'

which comes from this run.

It doesn't seem to be causing any issues running most of my tests, only the ones that are using pyte to test the visual output of my code, which leads me to believe the error itself might not be causing the break, but that it might be being output somewhere it shouldn't be (or I'm reading output from somewhere I shouldn't be).

Do I just need to suppress this error somehow or is this an actual bug?

[zanieb]

Can you point to the uv invocation you're using?

cc @BurntSushi

[pmbarrett314]

Here's the relevant job from my GitHub Action

  initial-test:
    name: Test One Version First
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Install uv
        uses: astral-sh/setup-uv@v3
        with:
          version: ${{ vars.UV_VERSION }}
          enable-cache: true
      - name: Set up Python
        run: uv python install ${{ vars.MAIN_PYTHON }}
      - name: Install the project
        run: uv sync --all-extras --dev
      - run: uv run pytest
        name: Run tests
      - run: uv run coverage lcov
        name: Generate coverage report for this run
      - name: Upload coverage report for this run to coveralls
        uses: coverallsapp/github-action@main
        with:
          github-token: ${{ secrets.github_token }}
          path-to-lcov: .cov/coverage.lcov
          parallel: true

[charliermarsh]

Do you see the same errors if you avoid using the shared GitHub Actions cache? Like with enable-cache = false? I'm trying to understand whether this is a cache compatibility issue (you have some data from pre-4.8, and we broke compatibility in 4.8) or a standalone issue on 4.8.

[pmbarrett314]

The issue initially showed up on 4.10, I deleted all of my caches and then tried a few different versions to narrow it down between 4.7 and 4.8. I'll set enable-cache to false and report back.

[pmbarrett314]

It does still output that error with enable-cache = false on 4.8 but not 4.7

[charliermarsh]

Okay thank you! If you run uv cache clean before uv python install, do you see the same thing?

[pmbarrett314]

I do indeed

[charliermarsh]

Thanks. I can replicate this just by cloning and running uv run pytest test/test_graphics.py::TestBasicMenu::test_basic_menu.

[pmbarrett314]

That does also happen for me.

[charliermarsh]

I can't replicate this as soon as I switch to a local uv build, even at the same commit.

[charliermarsh]

It looks like that job is running uv==0.3.1? I think this is just about the uv resolution in the subprocess or something.

[charliermarsh]

I think when you run uv run pytest test/test_graphics.py::TestBasicMenu::test_basic_menu, then inner uv run command is then going to resolve to the uv version of the project.

[pmbarrett314]

Yep, updating the uv requirement in uv.lock followed by uv cache clean fixes that on my local machine. Do y'all have any thoughts on my janky "uv-within-uv" scenario other than just making sure I keep the lockfile up to date with the version I'm using in Actions?

[charliermarsh]

(I do think there may still be a bug here, maybe we forgot to bump a cache version somewhere between 0.3.1 and 0.4.10.)

[charliermarsh]

Actually, perhaps our behavior is correct... The main issue is we included a change in the cache such that 0.4.7 entries can be read by 0.4.8, but not the other way around.

[charliermarsh]

I think my suggestion would be to pin the uv version within your pyproject.toml. Alternatively, you might want to use a dedicated, separate cache directory for the runs within the project? Like, pass --cache-dir ./foo to the uv run subprocess calls.

[pmbarrett314]

That sounds good, thanks for looking into it!