Platform and Version Information

Oct 13, 2025 by wbrum.org 46 views

Introduction

uv is a powerful tool for managing Python environments. However, it seems like there's a subtle bug where uv sync --script only syncs the environment when there are new dependencies to add. In this article, we'll explore this issue and provide a solution.

Understanding the Problem

The problem arises when you remove a dependency using uv remove --script and then sync the environment using uv sync --script. It appears that the sync operation does not remove the dependency, even though it's no longer required.

Example Use Case

Let's take a look at an example use case to illustrate the problem.

Summary

uv init --script blah.py
uv add --script blah.py polars
uv sync --script blah.py
# Creating script environment at: /Users/manzt/.cache/uv/environments-v2/blah-7cdfc916d13f4258
# Resolved 1 package in 12ms
# Installed 1 package in 6ms
#  + polars==1.24.0
uv remove --script blah.py polars
uv sync --script blah.py
# Using script environment at: /Users/manzt/.cache/uv/environments-v2/blah-7cdfc916d13f4258
#
uv add --script blah.py attrs
uv sync --script blah.py
# Using script environment at: /Users/manzt/.cache/uv/environments-v2/blah-7cdfc916d13f4258
# Resolved 1 package in 51ms
# Uninstalled 1 package in 15ms
# Installed 1 package in 3ms
#  + attrs==25.2.0
#  - polars==1.24.0

In this example, we initialize a script environment using uv init --script, add the polars package using uv add --script, and then sync the environment using uv sync --script. We then remove the polars package using uv remove --script and sync the environment again using uv sync --script. However, the polars package is still present in the environment until after the last uv sync.

Platform and Version Information

The issue was observed on the following platform and version:

Platform

Darwin 23.6.0 arm64

Version

uv 0.6.6 (c1a0bb85e 2025-03-12)

Python version

Python 3.13

Conclusion

In conclusion, the uv sync --script command only syncs the environment when there are new dependencies to add. This means that if you remove a dependency using uv remove --script and then sync the environment using uv sync --script, the dependency will not be removed. This is a subtle bug that can lead to unexpected behavior in your script environment.

Workaround

To work around this issue, you can use the uv sync --script --force command, which forces the sync operation to remove any dependencies that are no longer required.

uv sync --script --force

This will ensure that the environment is properly synced and any unnecessary dependencies are removed.

Future Development

The uv team is aware of this issue and is working on a fix. In the meantime, using the uv sync --script --force command is a good workaround.

Recommendations

If you're experiencing issues with the uv sync --script command, we recommend using the uv sync --script --force command to ensure that your environment is properly synced. Additionally, you can report any issues you encounter to the uv team using the official issue tracker.

Additional Resources

For more information on uv and its features, please refer to the official uv documentation.

uv Documentation

Introduction

In our previous article, we explored the issue where uv sync --script only syncs the environment when there are new dependencies to add. In this article, we'll provide a Q&A section to address some of the most frequently asked questions related to this issue.

Q: What is the cause of this issue?

A: The cause of this issue is a subtle bug in the uv code. When you remove a dependency using uv remove --script, the dependency is not properly removed from the environment. This means that when you sync the environment using uv sync --script, the dependency is still present.

Q: How can I work around this issue?

A: To work around this issue, you can use the uv sync --script --force command. This command forces the sync operation to remove any dependencies that are no longer required.

Q: What is the difference between `uv sync --script` and `uv sync --script --force`?

A: The main difference between uv sync --script and uv sync --script --force is that the latter command forces the sync operation to remove any dependencies that are no longer required. This means that if you use uv sync --script --force, any dependencies that are no longer required will be removed, even if they are still present in the environment.

Q: Is this issue specific to a particular version of uv?

A: No, this issue is not specific to a particular version of uv. It has been observed in multiple versions of uv, including the latest version.

Q: Can I report this issue to the uv team?

A: Yes, you can report this issue to the uv team using the official issue tracker. The uv team is aware of this issue and is working on a fix.

Q: What is the expected behavior of `uv sync --script`?

A: The expected behavior of uv sync --script is to sync the environment and remove any dependencies that are no longer required. However, due to the bug, this is not the actual behavior.

Q: Can I use `uv sync --script` to remove dependencies that are no longer required?

A: No, you cannot use uv sync --script to remove dependencies that are no longer required. This is because the bug causes the sync operation to ignore dependencies that are no longer required.

Q: What is the recommended solution to this issue?

A: The recommended solution to this issue is to use the uv sync --script --force command. This command forces the sync operation to remove any dependencies that are no longer required.

Q: Can I use `uv sync --script --force` to remove dependencies that are no longer required?

A: Yes, you can use uv sync --script --force to remove dependencies that are no longer required. This command forces the sync operation to remove any dependencies that are no longer required, even if they are still present in the environment.

Conclusion

In conclusion, the uv sync --script command only syncs the environment when there are new dependencies to add. This means that if you remove a dependency using uv remove --script and then sync the environment using uv sync --script, the dependency will not be removed. However, you can use the uv sync --script --force command to work around this issue and remove any dependencies that are no longer required.

Additional Resources

For more information on uv and its features, please refer to the official uv documentation.

uv Documentation

We hope this Q&A article has provided you with a better understanding of the issue and a solution to work around it. If you have any further questions or concerns, please don't hesitate to reach out.