pytest --version should also display information about installed plugins

[ssbarnea]

At this moment pytest --version does only output one line with its current version, missing to mention other essential informations which do affect its execution: installed plugins and python version.

Based on other tools that support plugins I dare to suggest extending the display to something similar with tox output:

$ tox --version
3.21.3 imported from /Users/ssbarnea/.pyenv/versions/3.8.6/lib/python3.8/site-packages/tox/__init__.py
registered plugins:
    tox-envreport-0.2.1 at /Users/ssbarnea/.pyenv/versions/3.8.6/lib/python3.8/site-packages/tox_envreport/plugin.py
    tox-ansible-1.0.5.dev1 at /Users/ssbarnea/c/a/tox-ansible/src/tox_ansible/hooks.py

I do not have a strong opinion regarding if those paths should be printed, but plugins and their versions are essential.

Also it would be wise to assure that the first line still starts with pytest <version>, so it would be unlikely to break parsing of version, if anyone did this. I mention this because recently Ansible managed to break even this, by adding some other bit between tool name and the version... :p

[The-Compiler]

It already does this with --version --version - see #7169 and #7128. Given that the change was introduced because some people felt --version was too verbose (and there's precedence for repeating the argument for more verbose version info in other tools), I don't see a reason to go back.

[ssbarnea]

Ooops, I kinda deserve a RTFM on that..... It is the first time when I see that --version is used like that, maybe I would have seen more logic on enabling it via -v instead of repeating it. Anyway sorry for creating a false bug report and thanks!

[nicoddemus]

maybe I would have seen more logic on enabling it via -v instead of repeating it

That was the original idea, but other tools (including Python) follow the same approach: #3692 (comment)

[ssbarnea]

I did not see this documented on https://clig.dev/ but it would not be a bad idea to make a pull-request to improve it and to mention that displaying version twice could display more information. That guide is very useful for anyone writing CLI tools.