`uv python find` doesn't find `python3.12` binary in $PATH when looking for `==3.12.8`

[aDotInTheVoid]

On my system I have both python3.13.0 and python3.12.8 installed through homebrew:

% which python3
/opt/homebrew/bin/python3
% which python3.12
/opt/homebrew/bin/python3.12
% python3 --version
Python 3.13.0
% python3.12 --version
Python 3.12.8

uv python list is aware of both of them:

% cat ~/.config/uv/uv.toml
python-preference = "only-system"

% uv python list
cpython-3.13.0-macos-aarch64-none    /opt/homebrew/opt/python@3.13/bin/python3.13 -> ../Frameworks/Python.framework/Versions/3.13/bin/python3.13
cpython-3.12.8-macos-aarch64-none    /opt/homebrew/opt/python@3.12/bin/python3.12 -> ../Frameworks/Python.framework/Versions/3.12/bin/python3.12
cpython-3.9.6-macos-aarch64-none     /Applications/Xcode.app/Contents/Developer/usr/bin/python3 -> ../../Library/Frameworks/Python3.framework/Versions/3.9/bin/python3

But can only find one of them:

% uv python find '==3.13.0'
/opt/homebrew/opt/python@3.13/bin/python3.13
% uv python find '==3.12.8'
error: No interpreter found for Python ==3.12.8 in virtual environments or search path

Or with more logging:

% RUST_LOG=uv=trace uv python list
DEBUG uv 0.5.6 (Homebrew 2024-12-03)
DEBUG Searching for any Python interpreter in search path
TRACE Searching PATH for executables: python, python3, cpython, cpython3, pypy, pypy3, graalpy, graalpy3
TRACE Checking `PATH` directory for interpreters: /opt/homebrew/bin
TRACE Found possible Python executable: /opt/homebrew/bin/python3
TRACE Cached interpreter info for Python 3.13.0, skipping probing: /opt/homebrew/bin/python3
DEBUG Found `cpython-3.13.0-macos-aarch64-none` at `/opt/homebrew/bin/python3` (search path)
TRACE Found possible Python executable: /opt/homebrew/bin/python3.12
TRACE Cached interpreter info for Python 3.12.8, skipping probing: /opt/homebrew/bin/python3.12
DEBUG Found `cpython-3.12.8-macos-aarch64-none` at `/opt/homebrew/bin/python3.12` (search path)
TRACE Found possible Python executable: /opt/homebrew/bin/python3.13
TRACE Cached interpreter info for Python 3.13.0, skipping probing: /opt/homebrew/bin/python3.13
DEBUG Found `cpython-3.13.0-macos-aarch64-none` at `/opt/homebrew/bin/python3.13` (search path)
TRACE Checking `PATH` directory for interpreters: /opt/homebrew/sbin
TRACE Checking `PATH` directory for interpreters: /usr/local/bin
TRACE Checking `PATH` directory for interpreters: /System/Cryptexes/App/usr/bin
TRACE Checking `PATH` directory for interpreters: /usr/bin
TRACE Found possible Python executable: /usr/bin/python3
TRACE Querying interpreter executable at /usr/bin/python3
DEBUG Found `cpython-3.9.6-macos-aarch64-none` at `/usr/bin/python3` (search path)
TRACE Checking `PATH` directory for interpreters: /bin
TRACE Checking `PATH` directory for interpreters: /usr/sbin
TRACE Checking `PATH` directory for interpreters: /sbin
TRACE Checking `PATH` directory for interpreters: /Library/Apple/usr/bin
TRACE Checking `PATH` directory for interpreters: /Users/aloenr01/.cargo/bin
TRACE Checking `PATH` directory for interpreters: /Applications/iTerm.app/Contents/Resources/utilities
cpython-3.13.0-macos-aarch64-none    /opt/homebrew/opt/python@3.13/bin/python3.13 -> ../Frameworks/Python.framework/Versions/3.13/bin/python3.13
cpython-3.12.8-macos-aarch64-none    /opt/homebrew/opt/python@3.12/bin/python3.12 -> ../Frameworks/Python.framework/Versions/3.12/bin/python3.12
cpython-3.9.6-macos-aarch64-none     /Applications/Xcode.app/Contents/Developer/usr/bin/python3 -> ../../Library/Frameworks/Python3.framework/Versions/3.9/bin/python3

% RUST_LOG=uv=trace uv python find '==3.13.0'
DEBUG uv 0.5.6 (Homebrew 2024-12-03)
DEBUG Using Python request `==3.13.0` from explicit request
DEBUG Searching for Python ==3.13.0 in virtual environments or search path
TRACE Searching PATH for executables: python3, python
TRACE Checking `PATH` directory for interpreters: /opt/homebrew/bin
TRACE Found possible Python executable: /opt/homebrew/bin/python3
TRACE Cached interpreter info for Python 3.13.0, skipping probing: /opt/homebrew/bin/python3
DEBUG Found `cpython-3.13.0-macos-aarch64-none` at `/opt/homebrew/bin/python3` (search path)
/opt/homebrew/opt/python@3.13/bin/python3.13

% RUST_LOG=uv=trace uv python find '==3.12.8'
DEBUG uv 0.5.6 (Homebrew 2024-12-03)
DEBUG Using Python request `==3.12.8` from explicit request
DEBUG Searching for Python ==3.12.8 in virtual environments or search path
TRACE Searching PATH for executables: python3, python
TRACE Checking `PATH` directory for interpreters: /opt/homebrew/bin
TRACE Found possible Python executable: /opt/homebrew/bin/python3
TRACE Cached interpreter info for Python 3.13.0, skipping probing: /opt/homebrew/bin/python3
DEBUG Found `cpython-3.13.0-macos-aarch64-none` at `/opt/homebrew/bin/python3` (search path)
DEBUG Skipping interpreter at `/opt/homebrew/opt/python@3.13/bin/python3.13` from search path: does not satisfy request `==3.12.8`
TRACE Checking `PATH` directory for interpreters: /opt/homebrew/sbin
TRACE Checking `PATH` directory for interpreters: /usr/local/bin
TRACE Checking `PATH` directory for interpreters: /System/Cryptexes/App/usr/bin
TRACE Checking `PATH` directory for interpreters: /usr/bin
TRACE Found possible Python executable: /usr/bin/python3
TRACE Querying interpreter executable at /usr/bin/python3
DEBUG Found `cpython-3.9.6-macos-aarch64-none` at `/usr/bin/python3` (search path)
DEBUG Skipping interpreter at `/Applications/Xcode.app/Contents/Developer/usr/bin/python3` from search path: does not satisfy request `==3.12.8`
TRACE Checking `PATH` directory for interpreters: /bin
TRACE Checking `PATH` directory for interpreters: /usr/sbin
TRACE Checking `PATH` directory for interpreters: /sbin
TRACE Checking `PATH` directory for interpreters: /Library/Apple/usr/bin
TRACE Checking `PATH` directory for interpreters: /Users/aloenr01/.cargo/bin
TRACE Checking `PATH` directory for interpreters: /Applications/iTerm.app/Contents/Resources/utilities
error: No interpreter found for Python ==3.12.8 in virtual environments or search path

What I think is happening is that uv python list code does this:

uv/crates/uv-python/src/discovery.rs

Lines 499 to 501 in 3aaa959

	.chain(find_all_minor(implementation, version, &dir_clone))
	.filter(|path| !is_windows_store_shim(path))
	.inspect(|path| trace!("Found possible Python executable: {}", path.display()))

where the find_all_minor means it can pick up on /opt/homebrew/bin/python3.12.

But when asking for ==3.12.8 specifically, it doesn't consider that 3.12 could be it:

uv/crates/uv-python/src/discovery.rs

Lines 579 to 581 in 3aaa959

	VersionRequest::MajorMinor(_, _, _)
	| VersionRequest::MajorMinorPatch(_, _, _, _)
	| VersionRequest::MajorMinorPrerelease(_, _, _, _) => Either::Right(iter::empty()),

_Originally posted by in #9668, but that issue was unrelated. CC @zanieb _

System Information:

• uv 0.5.6 (Homebrew 2024-12-03)
• macOS Sonoma 14.7.1 (23H222)
• arm64

[zanieb]

Thank you!

Does uv python find 3.12.8 work? (instead of uv python find ==3.12.8)

[aDotInTheVoid]

Does uv python find 3.12.8 work?

Yes it does:

% uv python find 3.12.8
/opt/homebrew/opt/python@3.12/bin/python3.12

Although this doesn't work in the requires-python field of pyproject.toml (sorry, I maybe should have put this in the issue, not sure if it's the same codepath or not):

% uv sync
error: Failed to parse: `pyproject.toml`
  Caused by: TOML parse error at line 4, column 19
  |
4 | requires-python = "3.12.8"
  |                   ^^^^^^^^
Failed to parse version: Unexpected end of version specifier, expected operator:
3.12.8
^^^^^^

And with requires-python = "==3.12.8" if fails in the same way as before:

% uv sync
error: No interpreter found for Python ==3.12.8 in search path

Full Log

% rm -rf ./.venv
% RUST_LOG=uv=trace  uv sync
DEBUG uv 0.5.6 (Homebrew 2024-12-03)
DEBUG Found project root: `/Users/alona/dev/feeds`
DEBUG No workspace root found, using project root
DEBUG Using Python request `==3.12.8` from `requires-python` metadata
DEBUG Searching for Python ==3.12.8 in search path
TRACE Searching PATH for executables: python3, python
TRACE Checking `PATH` directory for interpreters: /Users/alona/.vscode/extensions/ms-python.python-2024.20.0-darwin-arm64/python_files/deactivate/zsh
TRACE Checking `PATH` directory for interpreters: /Users/alona/.vscode/extensions/ms-python.python-2024.20.0-darwin-arm64/python_files/deactivate/zsh
TRACE Checking `PATH` directory for interpreters: /opt/homebrew/bin
TRACE Found possible Python executable: /opt/homebrew/bin/python3
TRACE Cached interpreter info for Python 3.13.0, skipping probing: /opt/homebrew/bin/python3
DEBUG Found `cpython-3.13.0-macos-aarch64-none` at `/opt/homebrew/bin/python3` (search path)
DEBUG Skipping interpreter at `/opt/homebrew/opt/python@3.13/bin/python3.13` from search path: does not satisfy request `==3.12.8`
TRACE Checking `PATH` directory for interpreters: /opt/homebrew/sbin
TRACE Checking `PATH` directory for interpreters: /usr/local/bin
TRACE Checking `PATH` directory for interpreters: /System/Cryptexes/App/usr/bin
TRACE Checking `PATH` directory for interpreters: /usr/bin
TRACE Found possible Python executable: /usr/bin/python3
TRACE Querying interpreter executable at /usr/bin/python3
DEBUG Found `cpython-3.9.6-macos-aarch64-none` at `/usr/bin/python3` (search path)
DEBUG Skipping interpreter at `/Applications/Xcode.app/Contents/Developer/usr/bin/python3` from search path: does not satisfy request `==3.12.8`
TRACE Checking `PATH` directory for interpreters: /bin
TRACE Checking `PATH` directory for interpreters: /usr/sbin
TRACE Checking `PATH` directory for interpreters: /sbin
TRACE Checking `PATH` directory for interpreters: /Library/Apple/usr/bin
TRACE Checking `PATH` directory for interpreters: /Users/alona/.cargo/bin
TRACE Checking `PATH` directory for interpreters: /Applications/iTerm.app/Contents/Resources/utilities
error: No interpreter found for Python ==3.12.8 in search path

[zanieb]

Ah okay thanks that's helpful context.

w.r.t.

uv/crates/uv-python/src/discovery.rs

Lines 579 to 581 in 3aaa959

	VersionRequest::MajorMinor(_, _, _)
	| VersionRequest::MajorMinorPatch(_, _, _, _)
	| VersionRequest::MajorMinorPrerelease(_, _, _, _) => Either::Right(iter::empty()),

we should be in the VersionRequest::Range case there. And if not, we should be returning the possible names in VersionRequest::executable_names

uv/crates/uv-python/src/discovery.rs

Line 1770 in cfd0079

pub(crate) fn executable_names(

I'm not sure what's going on yet.