upgrade pydot2 to be forward-setuptools-friendly

[tiborsimko]

Current behaviour

Yadage depends on pydot2 for visualisation:

$ rg -C 3 pydot2 setup.py 
49-        "viz": [
50-            # manually adding extras of adage[extra] because of pip
51-            # issue https://github.com/pypa/pip/issues/3189
52:            "pydot2",
53-            "pygraphviz",
54-            "pydotplus",
55-        ],

The last release of pydot2 happened in January 2014.

With the new versions of setuptools, this leads to installation problems. Here is a small demonstrator:

$ mkvirtualenv test -p python3.8
$ pip install --upgrade pip setuptools
$ cd src/yadage
$ pip install '.[viz]'
...
   Complete output (1 lines):
    error in pydot2 setup command: use_2to3 is invalid.

Workaround

Do not update setuptools, then things will work.

Expected behaviour

It would be really great to make yadage dependent on latest-greatest dot-handling packages, instead of relying on the too old pydot2 package. For example, upgrade to pydot, which is being actively maintained.

Notes

Ditto for other viz dependencies, e.g. pydotplus was last released in December 2014. (But it works with latest setuptools.)

[lukasheinrich]

I think @matthewfeickert found the same thing

[matthewfeickert]

I think @matthewfeickert found the same thing

Yup. For examples of where I had to move from pydot2 to pydot c.f.

• ci: Add CI using GitHub Actions workflows  adage#17
• ci: Fix Python tests CI workflow recast-hep/recast-atlas#43