PSR-12 for PHP and Airbnb's ESLint config for React requires LF line endings over CRLF. I see in the ESLint docs that they recommend adding a .gitattributes file with content similar to this:
*.js text eol=lf
I checked the Git documentation and it mentions that using eol can make paths be considered dirty. What is meant by this? I also notice there's mentions of core.safecrlf later in the docs, so can these types of conversions cause irreversible problems?
Will I also need to set core.autocrlf to false so that .gitattributes takes effect?
When you set a file in text mode in Git, that tells Git that you want it to perform end-of-line conversion. That means that Git will always write the file into its internal storage with LF endings, and then check out the endings that are specified, whether that's due to .gitattributes or various configuration options.
If, however, the repository already contains files with CRLF line endings checked in, then setting the eol option will cause the file to be checked into the repository with LF endings, as mentioned above. This will make Git think the file is modified, which it is. That's what's meant by making "the paths to be considered dirty."
The easiest way to solve this problem is to add the entries to .gitattributes, add the .gitattributes file, and then run git add --renormalize . and then commit. That way, any files which had CRLF endings will be converted to LF endings in the repository.
You don't also need to set core.autocrlf in addition. That behavior is overridden by the .gitattributes file.