commit e9fd8af09224316c5919d6e1da8b17506bf71bab
author Bruce Dawson <brucedawson@chromium.org> Mon Jun 20 23:59:57 2022
committer Chromium LUCI CQ <chromium-scoped@luci-project-accounts.iam.gserviceaccount.com> Mon Jun 20 23:59:57 2022
tree cca2fe8109e210cef40fe971dbc4c2796ea664b4
parent 1ceb137b6fbd29d5e27afbc743bd0655cdee1aad

Suppress new Pylint warnings in mb_unittest.py

mb_unittest.py has been clean under Pylint for a while, but recently
started showing these errors:

  99:22: W0613: Unused argument 'env' (unused-argument)
  99:32: W0613: Unused argument 'buffer_output' (unused-argument)
  99:52: W0613: Unused argument 'stdin' (unused-argument)
  119:21: W0613: Unused argument 'mode' (unused-argument)
  793:4: W0201: Attribute 'ToSrcRelPath' defined outside __init__ (attribute-defined-outside-init)
  800:4: W0201: Attribute 'ToSrcRelPath' defined outside __init__ (attribute-defined-outside-init)
  833:4: W0201: Attribute 'ToSrcRelPath' defined outside __init__ (attribute-defined-outside-init)
  842:4: W0201: Attribute 'ToSrcRelPath' defined outside __init__ (attribute-defined-outside-init)

A bit of bisecting showed that the cause is a depot_tools change -
crrev.com/c/3711282 - that reduces the number of parallel jobs in Pylint
to avoid hangs and long startup times. For this particular Pylint task
the job-count calculation worked out to just using one job and
apparently more checks are done in that case!

It was quite unexpected that adjusting the job count would trigger more
warnings. Testing with presubmit --all configured to do serial
Pylint checks everywhere didn't find any other errors.

The unused-argument warnings were suppressed with 'del', the
attribute-defined-outside-init warnings were suppressed by turning off
that warning for this Pylint task, and while I was in PRESUBMIT.py some previously suppressed warnings were turned back on and fixed
because they are trivial or no longer firing.

This change was tested with this command:

  git cl presubmit --force --files tools/mb/mb_unittest.py

In addition to the unused-argument and attribute-defined-outside-int
warnings appearing when the checking became serial, testing of this
change revealed that the spurious "Module 'PRESUBMIT' has no
'CheckFreeze'" warning only shows up when the checking is parallel.

Bug: 1309977, 1336854
Change-Id: I3326cbadee330a587d97710c11ffcbbc01ad3df9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3712154
Reviewed-by: Gabriel Charette <gab@chromium.org>
Commit-Queue: Bruce Dawson <brucedawson@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1016013}