maintainers.go: correct handling of globs

maintainers.go does not handle globs as described in MAINTAINERS.
Instead of only matching the files inside a directory, it also matches
everything below. Also, a glob used in between (`e.g. path/to/*/dir`)
could lead to matching many more paths unexpectedly.

This is caused by the way paths using globs are converted to regegular
expressions for use with gerrit:

1. The script converts all paths with trailing slash to a path with
   trailing glob. That means, a recursive match on a directory gets
   converted to match only the files in the directory (at least
   according to the documentation - if there wasn't 2).

   Example: `path/to/dir/` becomes `path/to/dir/*`

2. When converting the path to a regex, all globs get converted to
   prefix matching by replacing the glob by `.*`. Instead of only
   matching the files in the directory, everything below matches,
   which is a) not what the documentation states and b) the opposite
   of what 1. did first.

   Example: `path/to/dir/*` becomes `^path/to/dir/.*$`

In sum, this leads to all sorts of issues. Examples:
  - `path/*/dir`    becomes `^path/.*/dir$`
  - `path/to/dir/*` becomes `^path/to/dir/.*$`
  - `path/to/*.c`   becomes `^path/to/.*\.c$`

This change fixes that behaviour by:
- dropping the wrong conversion from 1. above.
- fixing glob matching by replacing `*` by `[^/]`.
- handling paths with trailing `/` as prefix, as documented.

The change was not split because these changes depend on each other and
splitting would break recursive matching between the commits.

Tests:
1. diffed output before and after is equal (!= the same)
2. manual testing of glob matching

Change-Id: I4347a60874e4f07e41bdee43cc312547bea99008
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/52275
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>

0 files changed, 0 insertions, 0 deletions