[BUG] Undeclared dependency on setuptools (pkg_resources)

[rodolfocarobene]

Hello,
recently, we encountered an error using Dash, related to the use of pkg_resources.

In particular, our project depends on dash, but not on setuptools (pkg_resources is distributed with it), so we were getting an error during testing:

.../.../.venv/lib/python3.9/site-packages/dash/dash.py", line 21, in <module>
    from pkg_resources import get_distribution, parse_version
ModuleNotFoundError: No module named 'pkg_resources'

The error is related to this line:

dash/dash/dash.py

Line 21 in db23cdc

from pkg_resources import get_distribution, parse_version

So at the moment dash is actually depending on setuptools without declaring it.

Moreover, the use of pkg_resources seems to be deprecated (https://setuptools.pypa.io/en/latest/pkg_resources.html) in favour of importlib.metadata (https://docs.python.org/3/library/importlib.metadata.html).

For our project, we can fix the issue adding the dependency on setuptools, but it's probably better if dash add it (or remove it completely).
Thanks in advance! :-)

[rodolfocarobene]

I think this is now fixed. Thanks!