`uv sync` hangs on 0.9.14 with PyPI proxy

[georgeflug]

Summary

This issue started happening on 0.9.14. It works OK on 0.9.13 or earlier.

When running uv sync, the command hangs indefinitely. This occurs when connecting to a PyPI proxy on Sonatype Nexus - it does not occur when using the PyPI index directly.

Repro steps:

1. Install uv 0.9.14
2. Clear caches and sync against PyPI (works OK): rm -rf .venv ~/.cache/uv && uv sync -vv
3. Clear caches and sync against Nexus (hangs): rm -rf .venv ~/.cache/uv && uv sync --index="https://nexus.mycompany.com/repository/PyPI/simple/" -vv

From the logs (see attached), it looks like it's waiting for a response for the hatchling metadata because I don't see the following entry when it hangs: TRACE Received package metadata for: hatchling

uv_sync_0.9.13.txt
uv_sync_0.9.14.txt

Platform

macOs and Ubuntu

Version

0.9.14

Python version

3.11.14

[zanieb]

Thanks for the report. Would you be willing to test a branch with a fix?

The changes between 13 and 14 are 0.9.13...0.9.14

Only #16887 looks suspicious but even that's a stretch.

[georgeflug]

The branch fixes it!

Interestingly, the branch and even the older 0.9.13 still have the problem if I run the build as cargo build -p uv. But when I run the build as cargo build --release, then 0.9.13, the branch, and everything leading up to f2c33b4 are good, and f2c33b4 through 0.9.14 are bad.

[zanieb]

Interesting. Thanks for giving it a try!

A revert will go out in the next release and we can investigate.

Would you be able to share the html response from the index? I'm not quite sure how we're going to reproduce the problem.

[georgeflug]

Thanks for reverting! Yes I can. What URL do you want to see?

[zanieb]

I believe the https://pypi.org/simple/hatchling/ equivalent is what we need. Does this happen for arbitrary packages?

[charliermarsh]

When possible, can you please follow-up with a response that we can use to reproduce this? Otherwise, we risk breaking you again in a subsequent PR, since we'll have no way of knowing if we've actually fixed your issue.

[georgeflug]

Sorry for the delay. See the attached request/response pulled from mitmproxy while uv sync ran. I was able to reproduce this with other packages besides hatchling, in this case, pyt.

pyt.log

The <script> tag at the bottom seems like a likely culprit since that's not present on pypi.org.

[charliermarsh]

Amazing, thank you.