feat: Add wildcards/regular expressions support to all options in _config.yml

[t1m013y]

Summary

My idea is to add wildcards/regular expressions support for all options in config file (_config.yml) that accepts file or directory (e.g. include, exclude, keep_files)

Motivation

I think this feature should be added to jekyll core because most text/code editors create additional files in project directory and they are not always in separate directory. I thint it would be comfortably to exclude these files by adding few regexp lines to config file instead of manually adding each file to ignore list.

Drawbacks

I don't see any big drawbacks in this feature. Maybe it can conflict with file/directory names that contains regexp characters like ^ or $ but I think it is unlikely that someone will create files/directories with regexp-like names. Also I have idea to add additional options like exclude_regexp, keep_files_regexp etc to avoid conflicts with usual files/directories names.

[mattr-]

Wildcards haven't traditionally been supported in those fields because they're unsafe due to path traversal attacks. While path traversal attacks don't have the same impact on a static site generator compared to a web server, we do need to be aware of and mitigate the problem somehow.

I would welcome a PR to support glob wildcards for these fields but adding regular expression support for these fields is not something I'm in favor of adding.

[t1m013y]

Wildcards haven't traditionally been supported in those fields because they're unsafe due to path traversal attacks.

How about adding separate options like exclude_regexp etc and printing warning if they are used?

[mattr-]

Wildcards haven't traditionally been supported in those fields because they're unsafe due to path traversal attacks.

How about adding separate options like exclude_regexp etc and printing warning if they are used?

No. Our config is full of too many options as it is.

[t1m013y]

Ok. Maybe I will make plugin later.