flatpak-builder can't process frozenlist

[brccabral]

Hi,
I am trying to create a Flatpak app that uses aiohttp which has frozenlist as dependency.
I used flatpak-pip-generator to create the dependencies, but when running flatpak-builder it fails with Cannot import 'pep517_backend.hooks'
I am not sure if it is related to #577

Details

# Generated with flatpak-pip-generator --runtime=org.gnome.Sdk//49 --yaml --requirements-file ../bigcam-requirements.txt --output ../bigcam-requirements
build-commands: []
buildsystem: simple
modules:
- name: python3-aiohttp
  buildsystem: simple
  build-commands:
  - pip3 install --verbose --exists-action=i --no-index --find-links="file://${PWD}"
    --prefix=${FLATPAK_DEST} "aiohttp==3.13.4" --no-build-isolation
  sources:
  - type: file
    url: https://files.pythonhosted.org/packages/0f/15/5bf3b99495fb160b63f95972b81750f18f7f4e02ad051373b669d17d44f2/aiohappyeyeballs-2.6.1-py3-none-any.whl
    sha256: f349ba8f4b75cb25c99c5c2d84e997e485204d2902a9597802b0371f09331fb8
  - type: file
    url: https://files.pythonhosted.org/packages/45/4a/064321452809dae953c1ed6e017504e72551a26b6f5708a5a80e4bf556ff/aiohttp-3.13.4.tar.gz
    sha256: d97a6d09c66087890c2ab5d49069e1e570583f7ac0314ecf98294c1b6aaebd38
  - type: file
    url: https://files.pythonhosted.org/packages/fb/76/641ae371508676492379f16e2fa48f4e2c11741bd63c48be4b12a6b09cba/aiosignal-1.4.0-py3-none-any.whl
    sha256: 053243f8b92b990551949e63930a839ff0cf0b0ebbe0597b0f3fb19e1a0fe82e
  - type: file
    url: https://files.pythonhosted.org/packages/64/b4/17d4b0b2a2dc85a6df63d1157e028ed19f90d4cd97c36717afef2bc2f395/attrs-26.1.0-py3-none-any.whl
    sha256: c647aa4a12dfbad9333ca4e71fe62ddc36f4e63b2d260a37a8b83d2f043ac309
  - type: file
    url: https://files.pythonhosted.org/packages/2d/f5/c831fac6cc817d26fd54c7eaccd04ef7e0288806943f7cc5bbf69f3ac1f0/frozenlist-1.8.0.tar.gz
    sha256: 3ede829ed8d842f6cd48fc7081d7a41001a56f1f38603f9d49bf3020d59a31ad
  - type: file
    url: https://files.pythonhosted.org/packages/0e/61/66938bbb5fc52dbdf84594873d5b51fb1f7c7794e9c0f5bd885f30bc507b/idna-3.11-py3-none-any.whl
    sha256: 771a87f49d9defaf64091e6e6fe9c18d4833f140bd19464795bc32d966ca37ea
  - type: file
    url: https://files.pythonhosted.org/packages/1a/c2/c2d94cbe6ac1753f3fc980da97b3d930efe1da3af3c9f5125354436c073d/multidict-6.7.1.tar.gz
    sha256: ec6652a1bee61c53a3e5776b6049172c53b6aaba34f18c9ad04f82712bac623d
  - type: file
    url: https://files.pythonhosted.org/packages/9e/da/e9fc233cf63743258bff22b3dfa7ea5baef7b5bc324af47a0ad89b8ffc6f/propcache-0.4.1.tar.gz
    sha256: f48107a8c637e80362555f37ecf49abe20370e557cc4ab374f04ec4423c97c3d
  - type: file
    url: https://files.pythonhosted.org/packages/23/6e/beb1beec874a72f23815c1434518bfc4ed2175065173fb138c3705f658d4/yarl-1.23.0.tar.gz
    sha256: 53b1ea6ca88ebd4420379c330aea57e258408dd0df9af0992e5de2078dc9f5d5

...
Processing ./aiohappyeyeballs-2.6.1-py3-none-any.whl (from aiohttp==3.13.4)
Processing ./aiosignal-1.4.0-py3-none-any.whl (from aiohttp==3.13.4)
Requirement already satisfied: attrs>=17.3.0 in /usr/lib/python3.13/site-packages (from aiohttp==3.13.4) (25.4.0)
Processing ./frozenlist-1.8.0.tar.gz (from aiohttp==3.13.4)
  Running command Preparing metadata (pyproject.toml)
  Preparing metadata (pyproject.toml) ... done
ERROR: Exception:
Traceback (most recent call last):
  File "/usr/lib/python3.13/site-packages/pip/_internal/cli/base_command.py", line 107, in _run_wrapper
    status = _inner_run()
  File "/usr/lib/python3.13/site-packages/pip/_internal/cli/base_command.py", line 98, in _inner_run
    return self.run(options, args)
           ~~~~~~~~^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/pip/_internal/cli/req_command.py", line 85, in wrapper
    return func(self, options, args)
  File "/usr/lib/python3.13/site-packages/pip/_internal/commands/install.py", line 388, in run
    requirement_set = resolver.resolve(
        reqs, check_supported_wheels=not options.target_dir
    )
  File "/usr/lib/python3.13/site-packages/pip/_internal/resolution/resolvelib/resolver.py", line 99, in resolve
    result = self._result = resolver.resolve(
                            ~~~~~~~~~~~~~~~~^
        collected.requirements, max_rounds=limit_how_complex_resolution_can_be
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/lib/python3.13/site-packages/pip/_vendor/resolvelib/resolvers/resolution.py", line 601, in resolve
    state = resolution.resolve(requirements, max_rounds=max_rounds)
  File "/usr/lib/python3.13/site-packages/pip/_vendor/resolvelib/resolvers/resolution.py", line 513, in resolve
    failure_criterion = self._attempt_to_pin_criterion(name)
  File "/usr/lib/python3.13/site-packages/pip/_vendor/resolvelib/resolvers/resolution.py", line 220, in _attempt_to_pin_criterion
    criteria = self._get_updated_criteria(candidate)
  File "/usr/lib/python3.13/site-packages/pip/_vendor/resolvelib/resolvers/resolution.py", line 211, in _get_updated_criteria
    self._add_to_criteria(criteria, requirement, parent=candidate)
    ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/pip/_vendor/resolvelib/resolvers/resolution.py", line 150, in _add_to_criteria
    if not criterion.candidates:
           ^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/pip/_vendor/resolvelib/structs.py", line 194, in __bool__
    return bool(self._sequence)
  File "/usr/lib/python3.13/site-packages/pip/_internal/resolution/resolvelib/found_candidates.py", line 165, in __bool__
    self._bool = any(self)
                 ~~~^^^^^^
  File "/usr/lib/python3.13/site-packages/pip/_internal/resolution/resolvelib/found_candidates.py", line 149, in <genexpr>
    return (c for c in iterator if id(c) not in self._incompatible_ids)
                       ^^^^^^^^
  File "/usr/lib/python3.13/site-packages/pip/_internal/resolution/resolvelib/found_candidates.py", line 39, in _iter_built
    candidate = func()
  File "/usr/lib/python3.13/site-packages/pip/_internal/resolution/resolvelib/factory.py", line 180, in _make_candidate_from_link
    base: BaseCandidate | None = self._make_base_candidate_from_link(
                                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        link, template, name, version
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/lib/python3.13/site-packages/pip/_internal/resolution/resolvelib/factory.py", line 226, in _make_base_candidate_from_link
    self._link_candidate_cache[link] = LinkCandidate(
                                       ~~~~~~~~~~~~~^
        link,
        ^^^^^
    ...<3 lines>...
        version=version,
        ^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/lib/python3.13/site-packages/pip/_internal/resolution/resolvelib/candidates.py", line 318, in __init__
    super().__init__(
    ~~~~~~~~~~~~~~~~^
        link=link,
        ^^^^^^^^^^
    ...<4 lines>...
        version=version,
        ^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/lib/python3.13/site-packages/pip/_internal/resolution/resolvelib/candidates.py", line 161, in __init__
    self.dist = self._prepare()
                ~~~~~~~~~~~~~^^
  File "/usr/lib/python3.13/site-packages/pip/_internal/resolution/resolvelib/candidates.py", line 238, in _prepare
    dist = self._prepare_distribution()
  File "/usr/lib/python3.13/site-packages/pip/_internal/resolution/resolvelib/candidates.py", line 329, in _prepare_distribution
    return preparer.prepare_linked_requirement(self._ireq, parallel_builds=True)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/pip/_internal/operations/prepare.py", line 543, in prepare_linked_requirement
    return self._prepare_linked_requirement(req, parallel_builds)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.13/site-packages/pip/_internal/operations/prepare.py", line 658, in _prepare_linked_requirement
    dist = _get_prepared_distribution(
        req,
    ...<3 lines>...
        self.check_build_deps,
    )
  File "/usr/lib/python3.13/site-packages/pip/_internal/operations/prepare.py", line 77, in _get_prepared_distribution
    abstract_dist.prepare_distribution_metadata(
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        build_env_installer, build_isolation, check_build_deps
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/lib/python3.13/site-packages/pip/_internal/distributions/sdist.py", line 71, in prepare_distribution_metadata
    self.req.prepare_metadata()
    ~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib/python3.13/site-packages/pip/_internal/req/req_install.py", line 530, in prepare_metadata
    self.metadata_directory = generate_metadata(
                              ~~~~~~~~~~~~~~~~~^
        build_env=self.build_env,
        ^^^^^^^^^^^^^^^^^^^^^^^^^
        backend=self.pep517_backend,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        details=details,
        ^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/lib/python3.13/site-packages/pip/_internal/operations/build/metadata.py", line 34, in generate_metadata
    distinfo_dir = backend.prepare_metadata_for_build_wheel(metadata_dir)
  File "/usr/lib/python3.13/site-packages/pip/_internal/utils/misc.py", line 715, in prepare_metadata_for_build_wheel
    return super().prepare_metadata_for_build_wheel(
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
        metadata_directory=metadata_directory,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        config_settings=cs,
        ^^^^^^^^^^^^^^^^^^^
        _allow_fallback=_allow_fallback,
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_impl.py", line 224, in prepare_metadata_for_build_wheel
    return self._call_hook(
           ~~~~~~~~~~~~~~~^
        "prepare_metadata_for_build_wheel",
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    ...<4 lines>...
        },
        ^^
    )
    ^
  File "/usr/lib/python3.13/site-packages/pip/_vendor/pyproject_hooks/_impl.py", line 402, in _call_hook
    raise BackendUnavailable(
    ...<4 lines>...
    )
pip._vendor.pyproject_hooks._impl.BackendUnavailable: Cannot import 'pep517_backend.hooks'
Error: module python3-aiohttp: Child process exited with code 2