Should we use mypy with pre-commit or with pytest images ?

[VannTen]

Is your feature request related to a problem? Please describe. I notice we use two ways of running mypy, via pre-commit, and via the thoth-pytest* image. We should remove one of those two, for the sake of consistency (+ less maintenance).

Here is my understanding of the two alternatives:

pre-commit:

• pros:
  • easy to upgrade (pre-commit autoupdate)
  • available for local development (identical to CI)
  • (In the future): hooks install can be shared between runs and repos (cache sharing once we have tekton pipelines in prow)
• cons:
  • types hints from other thoth packages are not available (AFAIK). We can probably fix that by having a types-thoth package with types-stub only (I think). Means some work.

separate image (same as pytest):

• pros:
  • install from the repo under test (if I read correctly) so has access to types hints from thoth-* packages it uses (at least, it should have).
• cons:
  • (Pretty much the reverse of pre-commit pros)

Any prefs ? @goern @harshad16

[goern]

I'd rate "local dev" as a huge pro, therefor I would prefer the pre-commit alternative

/kind documentation /priority important-soon

[VannTen]

/sig devsecops

[VannTen]

Actually, it looks like pytest has a --mypy option. So we could run it as one pytest test. One benefit is that it will complain when it will use types hints from installed dependency (should they not be in types-all) whereas pre-commit will not install anything from the repository.

(for example, compare the difference in output on current master of thoth-station/adviser bewteen pipenv run pytest and pre-commit run --all-files mypy` )