@spackbot fix style

Let me see if I can fix that for you!

I was able to run spack style --fix for you!

==> Running style checks on spack
  selected: isort, mypy, black, flake8
==> Modified files
  lib/spack/spack/directives.py
==> Running isort checks
  isort checks were clean
==> Running mypy checks
Success: no issues found in 556 source files
  mypy checks were clean
==> Running black checks
reformatted lib/spack/spack/directives.py
All done! ✨ 🍰 ✨
1 file reformatted.
  black checks were clean
==> Running flake8 checks
  flake8 checks were clean
==> spack style checks were clean

I've updated the branch with style fixes.

Why not just extracting the base class somewhere, like in fftw?

In some cases (*) we don't want to push changes upstream, since we can't guarantee that every function of the affected package will work - "our tests pass + no one complains = it just works" approach.

(*) Mostly for Python packages we remove version restrictions set by package authors, so some functionality not used by CMS could be affected; also for many packages we remove gettext dependency since we don't need other languages and we need to save on image size

@spackbot fix style

Let me see if I can fix that for you!

I was able to run spack style --fix for you!

==> Running style checks on spack
  selected: isort, mypy, black, flake8
==> Modified files
  lib/spack/spack/directives.py
==> Running isort checks
  isort checks were clean
==> Running mypy checks
Success: no issues found in 566 source files
  mypy checks were clean
==> Running black checks
reformatted lib/spack/spack/directives.py
All done! ✨ 🍰 ✨
1 file reformatted.
  black checks were clean
==> Running flake8 checks
  flake8 checks were clean
==> spack style checks were clean

I've updated the branch with style fixes.

In some cases (*) we don't want to push changes upstream, since we can't guarantee that every function of the affected package will work - "our tests pass + no one complains = it just works" approach.

(*) Mostly for Python packages we remove version restrictions set by package authors, so some functionality not used by CMS could be affected; also for many packages we remove gettext dependency since we don't need other languages and we need to save on image size

So, TLDR, a different use case: crude hacking of recipe vs special implementation of a common package.

Superseded by #35045