Runtime dependency on setuptools

[blaggacao]

Imported here:

commitizen/commitizen/changelog.py

Line 33 in b8fc1ee

import pkg_resources

Types of changes

Please put an x in the box that applies

• Bugfix

Without it in a pristine python environment:

cz --help
Traceback (most recent call last):
  File "/nix/store/8wvn1d6hfdcribcinn21rzlkvjvzab2p-python3.8-commitizen-1.23.0/bin/.cz-wrapped", line 6, in <module>
    from commitizen.cli import main
  File "/nix/store/k4h5dy9yqdm8gisdmbhzg75m06p1fb9z-python3-3.8.3-env/lib/python3.8/site-packages/commitizen/cli.py", line 9, in <module>
    from commitizen import commands, config
  File "/nix/store/k4h5dy9yqdm8gisdmbhzg75m06p1fb9z-python3-3.8.3-env/lib/python3.8/site-packages/commitizen/commands/__init__.py", line 1, in <module>
    from .bump import Bump
  File "/nix/store/k4h5dy9yqdm8gisdmbhzg75m06p1fb9z-python3-3.8.3-env/lib/python3.8/site-packages/commitizen/commands/bump.py", line 7, in <module>
    from commitizen.commands.changelog import Changelog
  File "/nix/store/k4h5dy9yqdm8gisdmbhzg75m06p1fb9z-python3-3.8.3-env/lib/python3.8/site-packages/commitizen/commands/changelog.py", line 6, in <module>
    from commitizen import changelog, factory, git, out
  File "/nix/store/k4h5dy9yqdm8gisdmbhzg75m06p1fb9z-python3-3.8.3-env/lib/python3.8/site-packages/commitizen/changelog.py", line 33, in <module>
    import pkg_resources

[blaggacao]

Not sure about the correct version constraint: please amend.

[blaggacao]

What would be a more appropriate version constraint? (this is latest on pypi as of today)

[woile]

Could you provide the full traceback? Thanks!

[blaggacao]

Could you provide the full traceback? Thanks!

Actually that's the full traceback when running cz --help - What where you expecting? (Or I'm misinterpreting?)

[woile]

I was expecting an exception at the end. It's not clear why it fails.
Which OS are you on?

[blaggacao]

Oh sorry! Might be that I clipped that unintentionally.

The exception was that pkg_resources is not importable.
This modules is made available by setuptools.

In a python environment without setuptools installed this results in an error as per the dependencies declared in the pyproject.toml.

In such a environment, the truth is: setuptools is a runtime dependency because of this import.

The python environment is the one crafted by the following nix expression:

   4   │   mach-nix = import (
   5   │     builtins.fetchGit {
   6   │       url = "https://github.com/DavHau/mach-nix/";
   7   │       ref = "2.0.1";
   8   │     }
   9   │   );
  10   │
  11   │   commitizenPython = mach-nix.mkPython {
  12   │     python = pkgs.python38;
  13   │     requirements = ''
  14   │       commitizen
  15   │       setuptools
  16   │     '';
  17   │   };

What this does:

1. takes a bare pkgs.python38
2. adds commitizen (from pypi)
3. additionally declares (unexposed) dependency setuptools - this is the motivation for this PR

With this setup it works. If I left setuptools undeclared, it would result in the exception.

Hypothesis: In most common standard python environments setuptools might be shipped or available.
But that doesn't change the fact that it still is a runtime dependency.

[blaggacao]

Note: https://github.com/DavHau/mach-nix/ has it's build in completely resolved dependency graph of all pypi packages (250MB database). This database is published every 12 hours or so and used for static dependency resolution. Since setuptools is not declared, the tool cannot generate the complete runtime closure for commitizen and I have to complement it manually.

[blaggacao]

@woile Apologies for the noise... Does my latter explanation make sense? I still wonder what an appropriate version of setuptools would be, though.

[woile]

Hey, yes, thanks, I gotta research now, I don't want to run in the issue that it doesn't work in a machine which already has setuptools.

[blaggacao]

Yeah, I understand. I think tagging the lowest possible setuptools version, which also implements pkg_resouces, upwards could be pretty safe.

[woile]

We have removed the dependency 🎉 You can try the latest version 💪