Re: git-apply does not work in a sub-directory of a Git repository

On Thu, Mar 24, 2016 at 11:50 PM, Junio C Hamano [off-list ref] wrote:

Nguyễn Thái Ngọc Duy  [off-list ref] writes:

quoted

quoted

On Wed, Mar 23, 2016 at 11:55 PM, Junio C Hamano [off-list ref] wrote:

quoted

The include/exclude mechanism does use wildmatch() but does not use
the pathspec mechanism (it predates the pathspec machinery that was
made reusable in places like this).  We should be able to

    $ cd d/e/e/p/d/i/r
    $ git apply --include=:/ ../../../../../../../patch

to lift this limitation.  IOW, we can think of the use_patch() to
include only the paths in the subdirectory we are in by default, but
we can make it allow --include/--exclude command line option to
override that default.

I went with a new option instead of changing --include.

It might be a "workable" band-aid, but would be an unsatisfying UI
if it were the endgame state.  You do not say "git grep --whole" (by
the way, "whole" is a bad option name, as you cannot tell "100% of
*what*" you are referring to--what you are widening is the limit
based on the location in the directory structure, so the option name
should have some hint about it, e.g. "full-tree" or something) and
this command will become an odd-man-out.

I haven't thought things through, but thinking out aloud a few
points...

  An existing user/script may be working in a subdirectory of a huge
  working tree and relies on the current behaviour that outside world
  is excluded by default, and may be passing --exclude to further
  limit the extent of damage by applying the patch to a subset of
  paths in the current directory that itself is also huge.  And that
  use case would not be harmed by such a change.

  On the other hand, an existing user/script would not be passing an
  "--include" that names outside the current subdirectory to force
  them to be included, because it is known for the past 10 years not
  to have any effect at all.

Real-world .gitignore patterns have taught me that even if it does not
have any effect, it might still be present in some scripts, waiting
for a chance to bite me.

So a better alternative may be to conditionally disable the "Paths
outside are not touched regardless of --include" logic, i.e. we
exclude paths outside by default just as before, but if there is at
least one explicit "--include" given, we skip this "return 0".

That way, we do not have to commit to turning --include/--exclude to
pathspec (which I agree is a huge change in behaviour that may not
be a good idea) and we do not have to add "--full-tree" that is only
understood by "apply" but not other commands that operate on the
current directory by default.

But your suggestion is good and I can't think of any better. We could
introduce pathspec as ftiler after "--", but it does not look elegant,
and it overlaps with --include/--exclude.

Perhaps we can start to warn people if --include is specified but has
no effect for a cycle or two, then we can do as you suggested?
-- 
Duy