I'm experiencing massive slowdown when going from

2.16.0rc1

to

2.16.0.rc2

(or

2.16.0

) when running checks on BUILD files with

pants tailor --check update-build-files --check ::

- from checks of each file taking <1s to 5-25 seconds per file. I have parallelism set to

process_execution_local_parallelism=2

- problem goes away when this setting is changed to 1. This is a quite large repo, containing ~230 BUILD files.

Huh, would be good to pinpoint this

@happy-kitchen-89482 I figured this out; I've re-read the docs https://www.pantsbuild.org/docs/python-lockfiles#lockfiles-for-tools and noticed there's a syntax change for requirements, I missed that earlier. After changing:

[black]
interpreter_constraints = ["==3.8.*"]
install_from_resolve = "python-default"

to

[black]
interpreter_constraints = ["==3.8.*"]
install_from_resolve = "python-default"
requirements = ["//3rdparty/python:requirements-dev#black"]

it works without problems on 2.16.0 - so I'm not sure what was the default value in rc1 vs rc2, but it was a configuration issue on my side after all.

Ah cool. Although - if you omit

requirements

it should still work, it'll just use the entire lockfile, which is probably not what you want.

Makes sense, thanks!