Re: Strangeness with git-add and nested repositories

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

>  * "git add -- path/to/subdir/file", when any of path/, path/to/,
>    path/to/subdir/ is a Git repository that is different from the
>    current Git repository, must fail.

If any of the leading directories in that long path is actually a
git repository that is different from the current one, it shouldn't
have added it.  IOW, adding the path is a bug.

"git add A/B/C" usually enforces this rule by

 - check A; if A is a separate repository (A/.git exists, etc.),
   do not add this path;

   - check A/B; if A/B is a separate repository, ignore;

     - check A/B/C; if A/B/C is a separate repository, ignore.
       otherwise add it.

When given multiple paths, e.g. "git add A/B/C A/D", it tries to
"optimize" things by first finding common leading directory (in this
case "A/") and doing something slightly different, and I think the
bug Andrew saw lies in that codepath.  It is likely that the code is
forgetting to make sure that there is no top of enclosed working
tree in the common leading directory part of the path.