How to unignore folder with a particular name (e.g. Sync) that can be located anywhere inside the repository and Recursively allow everything inside it, violating every other rule of gitignore?
The solution proposed (!/**/Sync/**/*) would not work alone, because It is not possible to re-include a file if a parent directory of that file is excluded.
So if you have a .gitignore with:
*
!.gitignore
You must whitelist folders first (!*/) and then exclude files (!**/Sync/**, no need for **/*)
The end result would be a .gitignore like:
*
!.gitignore
!*/
!**/Sync/**
Don't forget to check with any file which .gitignore rule applies with:
git check-ignore -v -- aFile
Note: / would be needed (for !**/Sync/**) if you wanted to anchor the whitelist from the top of your repository.
If not, no / needed: this would be relative to wherever your .gitignore is).
From gitignore man page:
If the pattern does not contain a slash
/, Git treats it as a shell glob pattern and checks for a match against the pathname relative to the location of the.gitignorefile (relative to the toplevel of the work tree if not from a.gitignorefile).