1713178 - Make `black` linter setup (really, all Python linters) avoid updating the virtualenv when they're already installed

Status: RESOLVED FIXED

(Developer Infrastructure :: Lint and Formatting, enhancement)

Description

[Nick Alexander :nalexander [he/him]]

Right now, the black linter's setup function always makes sure its virtualenv is fresh. That's correct, but very slow. (On my aging Macbook Pro, it's about ~8s of wall time. Linting with black, for comparison, takes ~1s for a small file.) We already fetch black's version for logging. I propose that we look for and version check the binary before we try to update it, hopefully speeding this up. This is, I think, what we do for eslint, which is much faster.

There are other slow Python-based linters as well that could use a similar process, but sadly extracting version numbers probably varies by tool.

Comment 1

[Nick Alexander :nalexander [he/him]]

Attachment: Bug 1713178 - Make `black` linter setup avoid updating the virtualenv if it's installed. r?ahal

This could be easily generalized to avoid the updating the virtualenv
more generally, but I think this functionality should be in the
virtualenv_manager -- something like install_pip_binary(...) -- so
I've just done the most impactful example here.

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a2dc0b41afce
Make `black` linter setup avoid updating the virtualenv if it's installed. r=ahal

Comment 3

[Iulian Moraru]

https://hg.mozilla.org/mozilla-central/rev/a2dc0b41afce