Error installing pact-python in Python 3.12 virtual environment: Invalid version string

[varun-prakash]

When I run pip install pact-python in a virtual environment using Python 3.12, I encounter the following error:

...\pip\_vendor\packaging\version.py", line 202, in __init__
    raise InvalidVersion(f"Invalid version: {version!r}")
pip._vendor.packaging.version.InvalidVersion: Invalid version: ''

I've already tried creating a new virtual environment and updating pip, but the issue still persists.

[JP-Ellis]

In order to properly diagnose the issue, I will need to have more information.

Can you please let me know:

• What operating system are you on?
• If on Windows, is this within WSL?
• What version of Pact Python (or the FFI/CLI packages) are you trying to install? Or just the latest?
• Can you share the output of pip --version
• Can you share the output of python --version
• Have you made sure that the virtual environment is properly activated by validating which pip or python command you are using? I.e., which pip and which python should find executables located within your venv.
• Is the issue also present of you use uv? I.e., instead of pip install ..., use uv pip install ... (and please also share uv --version if that also doesn't work).

You appear to have also omitted a large portion of the trace, so while I can see it is complaining about an invalid version, it is unclear which package this is coming from. Can you share it?

[antoniodellelce]

Same issue with python 3.13.7; it works specifying 2.3.3 instead of the latest 3.0.1

this is the output of installing running pip install pact_python with PIP_RESOLVER_DEBUG=1

$ pip install  pact_python
Reporter.starting()
Reporter.adding_requirement(SpecifierRequirement('pact_python'), None)
Collecting pact_python
  Using cached pact_python-3.0.1-py3-none-any.whl.metadata (11 kB)
Reporter.starting_round(0)
Reporter.adding_requirement(RequiresPythonRequirement('>=3.10'), LinkCandidate('https://files.pythonhosted.org/packages/9c/ff/e96767b7242cc00291b78cd5abb20a5c9ee1264c11061446f4195a7f9bb5/pact_python-3.0.1-py3-none-any.whl (from https://pypi.org/simple/pact-python/) (requires-python:>=3.10)'))
Reporter.adding_requirement(SpecifierRequirement('pact-python-ffi~=0.4.0'), LinkCandidate('https://files.pythonhosted.org/packages/9c/ff/e96767b7242cc00291b78cd5abb20a5c9ee1264c11061446f4195a7f9bb5/pact_python-3.0.1-py3-none-any.whl (from https://pypi.org/simple/pact-python/) (requires-python:>=3.10)'))
Collecting pact-python-ffi~=0.4.0 (from pact_python)
  Using cached pact_python_ffi-0.4.28.2-cp310-abi3-macosx_12_0_arm64.whl.metadata (8.3 kB)
Reporter.adding_requirement(SpecifierRequirement('yarl~=1.0'), LinkCandidate('https://files.pythonhosted.org/packages/9c/ff/e96767b7242cc00291b78cd5abb20a5c9ee1264c11061446f4195a7f9bb5/pact_python-3.0.1-py3-none-any.whl (from https://pypi.org/simple/pact-python/) (requires-python:>=3.10)'))
Requirement already satisfied: yarl~=1.0 in /Users/antonio.dellelce/projects/v-env/lib/python3.13/site-packages (from pact_python) (1.22.0)

The stack trace is practically the same.

[billdirks]

We are hitting this in CI on the great-expectations repo. You can see the full ci output and backtrace here. The full configuration for this ci step is here.

We are using python 3.12 on ubuntu-latest and are trying to install pact-python>=2.0.1 when we hit this error. If I pin pact-python>=2.0.1,<3, the installation goes through successfully (it also was fine until the latest release of 3.0).

Here is the backtrace I am seeing:

Collecting pact-python-ffi~=0.4.0 (from pact-python>=2.0.1->-r /home/runner/work/great_expectations/great_expectations/reqs/requirements-dev-lite.txt (line 7))
  Downloading pact_python_ffi-0.4.28.2-cp310-abi3-manylinux_2_24_x86_64.manylinux_2_28_x86_64.whl.metadata (8.3 kB)
Collecting yarl~=1.0 (from pact-python>=2.0.1->-r /home/runner/work/great_expectations/great_expectations/reqs/requirements-dev-lite.txt (line 7))
  Downloading yarl-1.22.0-cp312-cp312-manylinux2014_x86_64.manylinux_2_17_x86_64.manylinux_2_28_x86_64.whl.metadata (75 kB)
ERROR: Exception:
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_internal/cli/base_command.py", line 107, in _run_wrapper
    status = _inner_run()
             ^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_internal/cli/base_command.py", line 98, in _inner_run
    return self.run(options, args)
           ^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_internal/cli/req_command.py", line 71, in wrapper
    return func(self, options, args)
           ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_internal/commands/install.py", line 393, in run
    requirement_set = resolver.resolve(
                      ^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_internal/resolution/resolvelib/resolver.py", line 98, in resolve
    result = self._result = resolver.resolve(
                            ^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_vendor/resolvelib/resolvers/resolution.py", line 596, in resolve
    state = resolution.resolve(requirements, max_rounds=max_rounds)
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_vendor/resolvelib/resolvers/resolution.py", line 508, in resolve
    failure_criterion = self._attempt_to_pin_criterion(name)
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_vendor/resolvelib/resolvers/resolution.py", line 220, in _attempt_to_pin_criterion
    criteria = self._get_updated_criteria(candidate)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_vendor/resolvelib/resolvers/resolution.py", line 210, in _get_updated_criteria
    for requirement in self._p.get_dependencies(candidate=candidate):
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_internal/resolution/resolvelib/provider.py", line 276, in <genexpr>
    return (r for r in candidate.iter_dependencies(with_requires) if r is not None)
                       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_internal/resolution/resolvelib/candidates.py", line 259, in iter_dependencies
    for r in requires:
             ^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_internal/metadata/importlib/_dists.py", line 220, in iter_dependencies
    elif not extras and req.marker.evaluate({"extra": ""}):
                        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_vendor/packaging/markers.py", line 347, in evaluate
    return _evaluate_markers(
           ^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_vendor/packaging/markers.py", line 239, in _evaluate_markers
    groups[-1].append(_eval_op(lhs_value, op, rhs_value))
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_vendor/packaging/markers.py", line 187, in _eval_op
    return spec.contains(lhs, prereleases=True)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_vendor/packaging/specifiers.py", line 552, in contains
    normalized_item = _coerce_version(item)
                      ^^^^^^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_vendor/packaging/specifiers.py", line 28, in _coerce_version
    version = Version(version)
              ^^^^^^^^^^^^^^^^
  File "/opt/hostedtoolcache/Python/3.12.11/x64/lib/python3.12/site-packages/pip/_vendor/packaging/version.py", line 202, in __init__
    raise InvalidVersion(f"Invalid version: {version!r}")
pip._vendor.packaging.version.InvalidVersion: Invalid version: ''
Error: Process completed with exit code 2.

[billdirks]

I can reproduce by setting up a new virtual environment and doing pip install pact-python:

python --version
# Python 3.12.9

python -m venv venv
source venv/bin/activate
pip install pact-python

which produces the same backtrace as above.

[JP-Ellis]

Thanks all for the feedback! Clearly something was botched in 3.0.1. I will investigate first thing in the morning, and then release 3.0.2.

UPDATE: As a stop-gap, it is possible to udr uv as a drop-in replacement for pip and it seems to work fine for me:

root@8db83ef7ae3e:/mwe# uv venv
Using CPython 3.12.11 interpreter at: /usr/local/bin/python
Creating virtual environment at: .venv
Activate with: source .venv/bin/activate

root@8db83ef7ae3e:/mwe# uv pip install pact-python
Resolved 8 packages in 205ms
Prepared 8 packages in 744ms
Installed 8 packages in 10ms
 + cffi==2.0.0
 + idna==3.10
 + multidict==6.7.0
 + pact-python==3.0.1
 + pact-python-ffi==0.4.28.2
 + propcache==0.4.0
 + pycparser==2.23
 + yarl==1.22.0

UPDATE 2: I have identified this as an issue with pip and the packaged version of packaging that it uses. See pypa/packaging#938 for the upstream issue.