Update: Improve perf not traversing default ignored dirs (fixes #5679)

[alberto]

Replaces #6215

[eslintbot]

LGTM

[mention-bot]

By analyzing the blame information on this pull request, we identified @IanVS, @gronke and @jrajav to be potential reviewers

[alberto]

Testing with PR on this repo:

$ time ./bin/eslint.js node_modules/

real    0m0.366s
user    0m0.329s
sys 0m0.050s

vs. master

$ time ./bin/eslint.js node_modules/

real    0m2.447s
user    0m2.199s
sys 0m0.276s

[gronke]

To entirely skip ignoring bower_components or node_modules when at least one pattern negates a path within them is a good compromise that will be an improvement for probably most of the use cases.

👍

[eslintbot]

LGTM

[ilyavolodin]

LGTM

[samccone]

This is good, and is a good first pass improvement :) 👍

[nzakas]

I'd call this getIgnoredFoldersGlobPatterns (our conventions have methods beginning with verbs)

[nzakas]

Looks great, just a couple of very small stylistic things.

[eslintbot]

LGTM

[alberto]

@nzakas PR updated

[nzakas]

LGTM. Awesome stuff!

[SimenB]

Any chance of doing a quick patch release of this?

Before: node_modules/.bin/eslint . 10.76s user 2.53s system 76% cpu 17.312 total
After: node_modules/.bin/eslint . 0.91s user 0.11s system 81% cpu 1.250 total

[ilyavolodin]

@SimenB We try to do releases every other Friday. So next release should be towards the end of this week.