setup: sanitize absolute and funny paths in get_pathspec()
The prefix_path() function called from get_pathspec() is
responsible for translating list of user-supplied pathspecs to
list of pathspecs that is relative to the root of the work
tree. When working inside a subdirectory, the user-supplied
pathspecs are taken to be relative to the current subdirectory.
Among special path components in pathspecs, we used to accept
and interpret only "." ("the directory", meaning a no-op) and
".." ("up one level") at the beginning. Everything else was
passed through as-is.
For example, if you are in Documentation/ directory of the
project, you can name Documentation/howto/maintain-git.txt as:
howto/maintain-git.txt
../Documentation/howto/maitain-git.txt
../././Documentation/howto/maitain-git.txt
but not as:
howto/./maintain-git.txt
$(pwd)/howto/maintain-git.txt
This patch updates prefix_path() in several ways:
- If the pathspec is not absolute, prefix (i.e. the current
subdirectory relative to the root of the work tree, with
terminating slash, if not empty) and the pathspec is
concatenated first and used in the next step. Otherwise,
that absolute pathspec is used in the next step.
- Then special path components "." (no-op) and ".." (up one
level) are interpreted to simplify the path. It is an error
to have too many ".." to cause the intermediate result to
step outside of the input to this step.
- If the original pathspec was not absolute, the result from
the previous step is the resulting "sanitized" pathspec.
Otherwise, the result from the previous step is still
absolute, and it is an error if it does not begin with the
directory that corresponds to the root of the work tree. The
directory is stripped away from the result and is returned.
- In any case, the resulting pathspec in the array
get_pathspec() returns omit the ones that caused errors.
With this patch, the last two examples also behave as expected.
Signed-off-by: Junio C Hamano <gitster@pobox.com>