## Summary
Some packages encode logic to embed the current commit SHA in the
version tag, when built within a Git repo. This typically results in an
invalid (non-compliant) version. Here's an example from `pylzma`:
ccb0e7cff3/version.py (L45).
This PR adds a phony, empty `.git` to the cache root, to ensure that any
`git` commands fail.
Closes https://github.com/astral-sh/uv/issues/1768.
## Test Plan
- Create a tag on the current commit, like `v0.5.0`.
- Build `pylzma`, using a cache _within_ the repo:
```
rm -rf foo
cargo run venv
cargo run pip install "pylzma @ 10ef072c3c/pylzma-0.5.0.tar.gz" --verbose --cache-dir bar
```
It's a little picky about the value, but that seems okay.
```
❯ ./target/debug/uv pip install trio
Audited 1 package in 4ms
❯ UV_NO_CACHE=true ./target/debug/uv pip install trio
Audited 1 package in 50ms
```
Closes#1382
First, replace all usages in files in-place. I used my editor for this.
If someone wants to add a one-liner that'd be fun.
Then, update directory and file names:
```
# Run twice for nested directories
find . -type d -print0 | xargs -0 rename s/puffin/uv/g
find . -type d -print0 | xargs -0 rename s/puffin/uv/g
# Update files
find . -type f -print0 | xargs -0 rename s/puffin/uv/g
```
Then add all the files again
```
# Add all the files again
git add crates
git add python/uv
# This one needs a force-add
git add -f crates/uv-trampoline
```
