lint: bring back sentry.lint.sentry_check:SentryCheck

[joshuarli]

Upgrading to flake8 3.5.0 caused pycodestyle's register_check to silently ignore our custom checker, so we're missing out on some linting. Fortunately, flake8 3.5.0 lets us use local plugins via setup.cfg as documented here.

[mattrobenolt]

So after being extremely mad at computers, this really is the only sensible way to do it now. There's not a way to programmatically register extensions/plugins without digging really deep into things that flake8 does not want you to dig deep into and would be too much of a hack.

but this also means that this snippet of config needs to exist in all repos that try to use our checks since it won't inherit from the sentry repo in my testing.

And lastly, now that it's actually running our checks, it points out linter violations that you introduced in a commit while linters weren't running. So fix that up. :)

[mattrobenolt]

Scanning all the repos I have, the only one that seems to actually do this ouside of this one are:

getsentry/getsentry and getsentry/sentry-plugins

[joshuarli]

@mattrobenolt so flake8 doesn't yet support file-level error ignores. It's currently possible with an additional plugin, but we probably don't want more stuff. I'd have to inline # noqa: B314 for every print statement (there are 15) in our lint engine. Or can just disable linting entirely on that one file with # flake8: noqa. What do you say?

[mattrobenolt]

Right. Just don’t use print. You can use like,

def echo(s, err=False):
  fp = sys.stderr if err else sys.stdout
  fp.write(s)
  fp.flush()

[joshuarli]

Note: we discussed this briefly outside of the issue and we're just going to noqa the print lines.

[joshuarli]

So the currently pinned pycodestyle 2.3.0 in #9000 is kind of buggy. For example:

(sentry) josh@akashi.local sentry lint/fix-sentry-check $ bin/lint --python src/sentry/deletions/__init__.py
/Users/josh/sentry/sentry/src/sentry/deletions/__init__.py:29:1: E302 expected 2 blank lines, found 1
/Users/josh/sentry/sentry/src/sentry/deletions/__init__.py:37:5: E306 expected 1 blank line before a nested definition, found 0
/Users/josh/sentry/sentry/src/sentry/deletions/__init__.py:38:5: E306 expected 1 blank line before a nested definition, found 0
/Users/josh/sentry/sentry/src/sentry/deletions/__init__.py:39:5: E306 expected 1 blank line before a nested definition, found 0
/Users/josh/sentry/sentry/src/sentry/deletions/__init__.py:40:5: E306 expected 1 blank line before a nested definition, found 0
/Users/josh/sentry/sentry/src/sentry/deletions/__init__.py:41:5: E306 expected 1 blank line before a nested definition, found 0
... like 50 more lines of this

Bumping to 2.3.1 fixes this, but the latest 2.4.0 does not work with flake8 3.5.0.