fix: Resolve incorrect platform specific dependency

[ewianda]

This change addresses a bug where pip.parse selects the wrong requirement entry when multiple extras are listed with platform-specific markers.

🔍 Problem:

In a requirements.txt generated by tools like uv or poetry, it's valid to have multiple entries for the same package, each with different extras and sys_platform markers, for example:

optimum[onnxruntime]==1.17.1 ; sys_platform == 'darwin'
optimum[onnxruntime-gpu]==1.17.1 ; sys_platform == 'linux'

The current implementation in [parse_requirements.bzl](https://github.com/bazel-contrib/rules_python/blob/032f6aa738a673b13b605dabf55465c6fc1a56eb/python/private/pypi/parse_requirements.bzl#L114-L126) uses a sort-by-length heuristic to select the “best” requirement when there are multiple entries with the same base name. This works well in legacy requirements.txt files where:

my_dep
my_dep[foo]
my_dep[foo,bar]

...would indicate an intent to select the most specific subset of extras (i.e. the longest name).

However, this heuristic breaks in the presence of platform markers, where extras are not subsets, but distinct variants. In the example above, Bazel mistakenly selects optimum[onnxruntime-gpu] on macOS because it's a longer match, even though it is guarded by a Linux-only marker.

✅ Fix:

This PR modifies the behavior to:

1. Add the requirement marker as part of the sorting key.
2. Then apply the longest-match logic to drop duplicate requirements with different extras but the same markers.

This ensures that only applicable requirements are considered during resolution, preserving correctness in multi-platform environments.

🧪 Before:

On macOS, the following entry is incorrectly selected:

optimum[onnxruntime-gpu]==1.17.1 ; sys_platform == 'linux'

✅ After:

Correct entry is selected:

optimum[onnxruntime]==1.17.1 ; sys_platform == 'darwin'

close #2690

[aignas]

Could you please add a CHANGELOG item for future reference?

[ewianda]

@aignas is this good to, merge. It is currently a blocker for us

[aignas]

Could you please also update the PR description to be more descriptive please? The PR template has good suggestions on how to structure it (i.e. the user visible change in behaviour should be explained).

[aignas]

The improvements to the requirements utility are great, thank you!

[ewianda]

@aignas I am getting

ERROR: /home/ewianda/.cache/bazel/_bazel_ewianda/da4b4cc49e0e621570c9e24d6f1eab95/external/rules_python~/python/private/pypi/extension.bzl:231:25: Traceback (most recent call last):
        File "/home/ewianda/.cache/bazel/_bazel_ewianda/da4b4cc49e0e621570c9e24d6f1eab95/external/rules_python~/python/private/pypi/extension.bzl", line 611, column 25, in _pip_impl
                mods = parse_modules(module_ctx)
        File "/home/ewianda/.cache/bazel/_bazel_ewianda/da4b4cc49e0e621570c9e24d6f1eab95/external/rules_python~/python/private/pypi/extension.bzl", line 487, column 36, in parse_modules
                out = _create_whl_repos(
        File "/home/ewianda/.cache/bazel/_bazel_ewianda/da4b4cc49e0e621570c9e24d6f1eab95/external/rules_python~/python/private/pypi/extension.bzl", line 231, column 25, in _create_whl_repos
                fail("Attempting to creating a duplicate library {} for {}".format(
Error in fail: Attempting to creating a duplicate library py_deps_311_optimum_py3_none_any_508bc55d for optimum

Where should I be looking to fix this

[ewianda]

NVM, it is coming from uv astral-sh/uv#8915 (comment)
optimum[onnxruntime-gpu]==1.17.1 ; sys_platform == 'linux'
optimum[onnxruntime]==1.17.1 ; sys_platform == 'darwin'

have same hashes so the repo name is thesame