Caching wheel files - does not refresh? #16617
Description
Summary
I am creating a wheel file out of my lib.
When testing the wheel, I use it outside of my repository - and to do that, I use uv run --isolated --refresh --with path/to/MYWHEEL.whl ...
That works once - but when I discover a bug and change the code + rebuild the wheel, uv keeps using the old wheel until I run uv cache prune.
According to the documentation, wheel files are cached via their modification time (source: https://docs.astral.sh/uv/concepts/cache/):
For local dependencies, uv caches based on the last-modified time of the source archive (i.e., the local .whl or .tar.gz file).
As my new wheel has a newer mtime, my expectation was that it would be picked up.
Is there any way uv could detect this by itself? Can I exclude certain packages from caching? This is in particular the case for local wheels which are being tested. Of course I usually want the dependencies of my wheel to come from cache (it might depend on huge packages like tensorflow, therefore disabling cache completely is not an option).
A simple reproducer is this script (run it in a temporary directory):
#!/bin/bash
set -e
uv --version
rm -rf bug
uv cache prune
uv init --lib bug
cd bug
uv build --wheel
stat dist/bug-0.1.0-py3-none-any.whl
cd ..
echo
echo "First call"
echo "-----------------------------------------------"
uv run --isolated --refresh --with bug/dist/bug-0.1.0-py3-none-any.whl python -c 'import bug; print(bug.hello())'
echo "-----------------------------------------------"
echo
cd bug
cat << EOF > src/bug/__init__.py
def hello() -> str:
return "Updated code!"
EOF
rm -f dist/bug-0.1.0-py3-none-any.whl # does not matter, but this ensures all times are different
uv build --wheel
stat dist/bug-0.1.0-py3-none-any.whl
cd ..
echo
echo "Trying to run modified wheel (no output from uv"
echo "about reinstallation, the printout is still the"
echo "old one."
echo "-----------------------------------------------"
uv run --isolated --refresh --with bug/dist/bug-0.1.0-py3-none-any.whl python -c 'import bug; print(bug.hello())'
echo "-----------------------------------------------"
echo
uv cache prune
echo
echo "Running modified wheel after cache pruning"
echo "Now the output is correct"
echo "-----------------------------------------------"
uv run --isolated --refresh --with bug/dist/bug-0.1.0-py3-none-any.whl python -c 'import bug; print(bug.hello())'
echo "-----------------------------------------------"The output is:
$ ./uv-chache-reproducer.sh
uv 0.9.7
Pruning cache at: /home/username/.cache/uv
Removed 35 files (31.9KiB)
Initialized project `bug` at `/tmp/bug`
Building wheel (uv build backend)...
Successfully built dist/bug-0.1.0-py3-none-any.whl
File: dist/bug-0.1.0-py3-none-any.whl
Size: 1364 Blocks: 8 IO Block: 4096 regular file
Device: 0,37 Inode: 6099 Links: 1
Access: (0664/-rw-rw-r--) Uid: ( 1000/username) Gid: ( 1000/username)
Access: 2025-11-06 18:41:21.143532545 +0100
Modify: 2025-11-06 18:41:21.144532555 +0100
Change: 2025-11-06 18:41:21.144532555 +0100
Birth: 2025-11-06 18:41:21.143532545 +0100
First call
-----------------------------------------------
Installed 1 package in 0.31ms
Hello from bug!
-----------------------------------------------
Building wheel (uv build backend)...
Successfully built dist/bug-0.1.0-py3-none-any.whl
File: dist/bug-0.1.0-py3-none-any.whl
Size: 1363 Blocks: 8 IO Block: 4096 regular file
Device: 0,37 Inode: 6100 Links: 1
Access: (0664/-rw-rw-r--) Uid: ( 1000/username) Gid: ( 1000/username)
Access: 2025-11-06 18:41:21.308534251 +0100
Modify: 2025-11-06 18:41:21.309534261 +0100
Change: 2025-11-06 18:41:21.309534261 +0100
Birth: 2025-11-06 18:41:21.308534251 +0100
Trying to run modified wheel (no output from uv
about reinstallation, the printout is still the
old one.
-----------------------------------------------
Hello from bug!
-----------------------------------------------
Pruning cache at: /home/username/.cache/uv
Removed 35 files (31.9KiB)
Running modified wheel after cache pruning
Now the output is correct
-----------------------------------------------
Installed 1 package in 0.30ms
Updated code!
-----------------------------------------------
As you can see, I get "Hello from bug!" twice, even after rebuilding the wheel. Only after pruning, the new wheel is used.
Platform
Linux 6.14.0-35-generic x86_64 GNU/Linux
Version
uv 0.9.7
Python version
Python 3.12.3