Extends #1029
Closes https://github.com/astral-sh/puffin/issues/1038
Instead of always using the current Python version for builds when a
target version is provided, we will do our best to use a compatible
Python version for builds.
Removes behavior where Python versions without patch versions were
always assumed to be the latest known patch version (previously
discussed in https://github.com/astral-sh/puffin/pull/534). While this
was convenient for resolutions which include packages which require
minimum patch versions e.g. `requires-python=">=3.7.4"`, it conflicts
with the idea that the target Python version you provide is the
_minimum_ compatible version. Additionally, it complicates interpreter
lookup as we cannot tell if the user has asked for that specific patch
version or not.
## Summary
This PR ensures that when the user passes in `--python-version`, we
adjust the _markers_ to match the target version, thus forcing us to
select compatible wheels for the `--python-version`, rather than the
installed version.
## Context
Let's call Python 3.10 the "installed" environment and Python 3.12 the
"target" environment. For each version, we have _both_ a Python version
(to match against `Requires-Python`) and a set of tags (to match against
wheels).
The rules for resolution are as follows...
- For each package, for each version, we try to find the "best
candidate" for resolution and installation.
- We first look for a wheel that's compatible with the _target_
environment. This requires testing against both the `Requires-Python`
and the markers. (We won't have to build or run this code, so the
_installed_ version is irrelevant.) **(This PR corrects _this_ bullet --
previously, we validated against the _installed_ markers, rather than
the target markers.)**
- If we can't find a compatible wheel, we accept any _incompatible_
wheel as long as there's a source distribution. The source distribution
_must_ be compatible with the target environment. (We won't have to
build or run this code, so the _installed_ version is irrelevant.)
- If there are no wheels, then the source distribution must be
compatible with _both_ the installed and target environments, since we
need to build it.
This is all true for the top-level resolution. When we perform a
sub-resolution (when resolving the build dependencies of a source
distribution), we should _only_ use the installed environment, and
ignore the target environment, since we assume that the dependencies
will be the same in both environments once built -- so our goal is
"just" to build the distribution, without concern for which build
dependencies it uses.
Closes https://github.com/astral-sh/puffin/issues/883.
The semantics are a bit unintuitive because `--python-version` is a
preference when looking for a python version without a venv, but if we
don't find that exact version we'll take `python3` and patch the
markers. This will make more sense once we start provisioning python
builds.
We can now resolve black with both python 3.8 and 3.12, with or without
that python version being in scope. In the example below,
`PATH=$HOME/.cargo/bin:/usr/bin` removes the pyenv builds and leaves
only `python3`, which is python 3.11.
```console
$ RUST_LOG=puffin::commands=debug cargo run --bin puffin -q -- pip-compile -v scripts/benchmarks/requirements/black.in --python-version py38
0.004108s DEBUG puffin::commands::pip_compile Using Python 3.8 at /home/konsti/.local/bin/python3.8
Resolved 8 packages in 44ms
# This file was autogenerated by Puffin v0.0.1 via the following command:
# puffin pip-compile -v scripts/benchmarks/requirements/black.in --python-version py38
black==23.11.0
[...]
platformdirs==4.0.0
# via black
tomli==2.0.1
# via black
typing-extensions==4.8.0
# via black
$ PATH=$HOME/.cargo/bin:/usr/bin RUST_LOG=puffin::commands=debug cargo run --bin puffin -q -- pip-compile -v scripts/benchmarks/requirements/black.in --python-version py38
0.004315s DEBUG puffin::commands::pip_compile Using Python 3.11 at /usr/bin/python3
Resolved 8 packages in 43ms
# This file was autogenerated by Puffin v0.0.1 via the following command:
# puffin pip-compile -v scripts/benchmarks/requirements/black.in --python-version py38
black==23.11.0
[...]
platformdirs==4.0.0
# via black
tomli==2.0.1
# via black
typing-extensions==4.8.0
# via black
```
```console
$ RUST_LOG=puffin::commands=debug cargo run --bin puffin -q -- pip-compile -v scripts/benchmarks/requirements/black.in --python-version py312
0.004216s DEBUG puffin::commands::pip_compile Using Python 3.12 at /home/konsti/.local/bin/python3.12
Resolved 6 packages in 37ms
# This file was autogenerated by Puffin v0.0.1 via the following command:
# puffin pip-compile -v scripts/benchmarks/requirements/black.in --python-version py312
black==23.11.0
[...]
platformdirs==4.0.0
# via black
$ PATH=$HOME/.cargo/bin:/usr/bin RUST_LOG=puffin::commands=debug cargo run --bin puffin -q -- pip-compile -v scripts/benchmarks/requirements/black.in --python-version py312
0.004190s DEBUG puffin::commands::pip_compile Using Python 3.11 at /usr/bin/python3
Resolved 6 packages in 39ms
# This file was autogenerated by Puffin v0.0.1 via the following command:
# puffin pip-compile -v scripts/benchmarks/requirements/black.in --python-version py312
black==23.11.0
[...]
platformdirs==4.0.0
# via black
```
Fixes#235.
Co-authored-by: Charlie Marsh <charlie.r.marsh@gmail.com>
Zanie Blue