uv sync rewrites python/uv.lock with metadata-only diffs on uv 0.9.x

[terasakisatoshi]

uv sync rewrites python/uv.lock with metadata-only diffs on newer uv releases

Summary

Running uv sync --offline in python/ can rewrite python/uv.lock even when the environment is already up to date and no dependency set has changed.

In my local reproduction with uv 0.9.10, the diff is metadata-only:

• revision = 1 becomes revision = 3
• package entries gain upload-time = ... fields
• the resolved package set does not materially change

This creates noisy contributor churn in a tracked lockfile from a routine setup command.

Reproduction steps

1. Use uv 0.9.10.

   uv --version

2. Start from a clean checkout where python/uv.lock matches the repository.

3. Run the documented setup command:

   cd python
   uv sync --offline

4. Check the diff:

   cd ..
   git diff -- python/uv.lock

5. Observe that python/uv.lock is rewritten with format/metadata changes such as revision = 3 and upload-time fields, despite no intentional dependency update.

Expected behavior

Routine contributor setup with uv sync should not rewrite python/uv.lock unless dependencies or the intended lockfile format for the repo have actually changed.

Actual behavior

uv sync introduces a large lockfile diff consisting of metadata-only changes.

Notes

Observed locally on:

• uv 0.9.10 (44f5a14f4 2025-11-17)

This is especially noticeable because the Python setup path in the repo documentation points contributors at uv sync.