Is it PyOpenSSL or pyOpenSSL or pyopenssl? With this change you don't
have to care. Write it as pYoPeNSsL for all I care¹.
Can we do it like that? Yes, we can. Distribution names should be matched
with `re.IGNORECASE` according to the wheel specification².
[1] https://packaging.python.org/en/latest/specifications/core-metadata/#name
[2] Just kidding, please make it look sane.
The usage of wheel should be restricted to the hook. I discovered this
when trying to remove wheel from the Python bootstrap. Some packages
that needed wheel did not need it added explicitly because they use this
hook. This implicit change to the dependency tree shouldn't happen (even
though it is mostly harmless).
Since the wheel file name is based on the package metadata instead of
what we set in the derivation, if you set the version as `unstable-YYYYMMDD`,
for example, the hook would silently fail. We will ignore the version
now and just use a glob instead to match anything that has the package
name in its path.
Fixes#248185.
Prior to this commit, pythonRelaxDeps would only support removing
version constraints from "Requires-Dist" lines formatted in a particular
way ("foo (>= 1.2.3)"). This way is deprecated as per PyPA Core Metadata
Specs v2.1 [1]:
> Tools parsing the format should accept optional parentheses around
> this, but tools generating it should not use parentheses.
Additionally, a "Requires-Dist" dependency specification can contain
other metadata than just package name and version (extra names,
environment marker). These were being silently dropped by the prior
version of pythonRelaxDeps, or the version could not be relaxed.
The actual grammar is defined in PEP 508 [2]. Our tool of choice here is
sed extended regexps, so there's only so much we can do to be correct
with this parser. The regexp implemented in this commit makes an attempt
at supporting [extra] names, ; env_markers, as well as version specs
without parentheses. There are still unsupported features (URL specs) as
well as unhandled edge cases, but at some point trying to make the
regexp better is bound to awake ZALGO [3].
[1] https://packaging.python.org/en/latest/specifications/core-metadata/#requires-dist-multiple-use
[2] https://peps.python.org/pep-0508/#grammar
[3] https://stackoverflow.com/a/1732454/179806
We have a common pattern here in nixpkgs for Python applications: when a
Python package ships with either a requirements.txt or setup.py file, we
generally end up having to modify its version restriction, otherwise we have
build failures since we package only one specific version of each package
normally.
However, this end up being done in a completely ad-hoc way: some people
use substituteInPlace, some others use sed, others uses patches, etc.
In many cases, the code ends up being buggy, so it may work in one
version and breaks on the next one. We can instead implement one
standard way of doing this, and trying to be a correct as possible.
So this is what this commit does: it implements a new build hook, that
when called will automatically patch the wheel file. This is one of the
most generic ways to patch Python dependencies, and should work in
multiple cases.
