Handle duplicated package metadata when using importlib.metadata

[kemzeb]

Fixes #341.

Using an environment similar to the one shown in the issue:

$ PYTHONPATH=/workspaces/pipdeptree/temp-site-pkgs/ pipdeptree -a -d 0
Warning!!! Duplicate package metadata found:
"/home/vscode/.local/lib/python3.9/site-packages"
  pluggy                           1.4.0            (using 1.4.0, "/workspaces/pipdeptree/temp-site-pkgs")
  packaging                        24.0             (using 24.0, "/workspaces/pipdeptree/temp-site-pkgs")
  tomli                            2.0.1            (using 2.0.1, "/workspaces/pipdeptree/temp-site-pkgs")
  pytest                           8.1.1            (using 8.1.1, "/workspaces/pipdeptree/temp-site-pkgs")
  exceptiongroup                   1.2.0            (using 1.2.0, "/workspaces/pipdeptree/temp-site-pkgs")
  iniconfig                        2.0.0            (using 2.0.0, "/workspaces/pipdeptree/temp-site-pkgs")
"/usr/local/lib/python3.9/site-packages"
  pip                              23.0.1           (using 24.0, "/home/vscode/.local/lib/python3.9/site-packages")
------------------------------------------------------------------------
chardet==5.2.0
covdefaults==2.3.0
coverage==7.4.4
diff_cover==8.0.3
distlib==0.3.8
exceptiongroup==1.2.0
filelock==3.13.3
gitdb==4.0.11
GitPython==3.1.41
iniconfig==2.0.0
Jinja2==3.1.3
MarkupSafe==2.1.5
packaging==24.0
pip==24.0
pipdeptree==2.16.3.dev3+g91d21e3.d20240403
platformdirs==4.2.0
pluggy==1.4.0
Pygments==2.17.2
pytest==8.1.1
pytest-cov==5.0.0
pytest-mock==3.14.0
setuptools==69.0.3
smmap==5.0.1
tomli==2.0.1
virtualenv==20.25.1
wheel==0.42.0

[kemzeb]

Make it a draft for now so that I can write a test or two and see if I can refactor the code at all 👍👍

[kemzeb]

One other thing I should mention, I think users who have an older pip installed on their system may get the duplicate metadata warning message as when they install pipdeptree they will also most likely install the latest pip version (and since the former pip is installed on the system it most likely won't be removed). Here's an example:

$ pipdeptree
Warning!!! Duplicate package metadata found:
"/usr/local/lib/python3.8/site-packages"
  pip                              23.0.1           (using 24.0, "/home/vscode/.local/lib/python3.8/site-packages")
------------------------------------------------------------------------
covdefaults==2.3.0
└── coverage [required: >=6.0.2, installed: 7.4.4]
diff_cover==8.0.3
├── chardet [required: >=3.0.0, installed: 5.2.0]
├── Jinja2 [required: >=2.7.1, installed: 3.1.3]
. . .

Should we accept this, or should we handle this special case in some way?

Edit: Now that I think about it, this will only happen if they are using a version of pip<23.1.2 (where pip install will just use the system-provided pip if it is >=23.1.2) so I don't think we need to handle this.

[kemzeb]

Gonna merge this and cut a 2.17.0 release!

[kemzeb]

Thanks re-running the workflow (not sure why coverage for _discovery.py was failing when it passed previously). Seeing that there are no further issues I'll cut a new release 👍