bug#34621: [PATCH] Fix rgrep in dired taking default search file pattern from directory name (e.g. *.11 for django-1.11)

[Juri Linkov]

> I've updated the patch following input from Drew and Juri.
> This now adds 'grep-default-file-pattern-function' which major modes
> can implement.
> Dired implements this to take the extension of the file at point, with
> a default of 'all',
> thus solving the issue I was having with the django-1.11 directory
> mentioned earlier in the thread.
> Behaviour for major modes that don't implement
> 'grep-default-file-pattern-function' will remain as before.

Thanks, this is better than previous versions.

Even more, you don't need any changes in dired.el.  Just use in grep.el

  (run-hook-with-args-until-success 'file-name-at-point-functions)

because 'file-name-at-point-functions' already has the right value in Dired.

You can call it at the very beginning of grep-read-files in the same 'or'
before buffer-file-name, so the existing code will take care about getting
its file extension.