What are magento2 blacklists?

Question

There is a grunt task black-list-generator that does this:

Running tasks: black-list-generator

Running "black-list-generator" task
Collect data from app/code/**/*.js: Start!
Collect data from app/code/**/*.js: Finish!
Collect data from app/design/**/*.js: Start!
Collect data from app/design/**/*.js: Finish!
Collect data from dev/tests/js/jasmine/tests/**/*.js: Start!
Collect data from dev/tests/js/jasmine/tests/**/*.js: Finish!
Collect data from lib/web/mage/**/*.js: Start!
Collect data from lib/web/mage/**/*.js: Finish!
The file was saved!

Done, without errors.

And some files with module names inside like:

vendor/magento/magento2-base/dev/tests/static/testsuite/Magento/Test/Integrity/Library/_files/blacklist.txt

But don't understand what that task actually does and how are blacklist.txt files used in the application.

Answer 1

Before merge new PR with bugs fixes and features the Magento 2 core teams run builds with different types of tests.

This blacklist.txt is used by the Magento static tests. Some js files, phtml views, etc. contain old code formatting, not verified escaping, docblock annotations, etc. and if remove this files from blacklists the Magento static tests will be failed.

During to refactor, the Magento core teams improve this legacy files to corresponding standards and remove refactored files from blacklist.