Re: [PATCH v2 4/4] mergetool: fix running in subdir when rerere enabled

On 2017-01-06 04:42, Johannes Sixt wrote:

Am 06.01.2017 um 02:09 schrieb Richard Hansen:

quoted

If rerere is enabled and no pathnames are given, run cd_to_toplevel
before running 'git diff --name-only' so that 'git diff --name-only'
sees the pathnames emitted by 'git rerere remaining'.

Also run cd_to_toplevel before running 'git rerere remaining' in case
'git rerere remaining' is ever changed to print pathnames relative to
the current directory rather than to $GIT_WORK_TREE.

This fixes a regression introduced in
57937f70a09c12ef484c290865dac4066d207c9c (v2.11.0).

Signed-off-by: Richard Hansen <redacted>
---
 git-mergetool.sh     | 1 +
 t/t7610-mergetool.sh | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/git-mergetool.sh b/git-mergetool.sh
index e52b4e4f2..67ea0d6db 100755
--- a/git-mergetool.sh
+++ b/git-mergetool.sh

@@ -456,6 +456,7 @@ main () {

     if test $# -eq 0 && test -e "$GIT_DIR/MERGE_RR"
     then
+        cd_to_toplevel
         set -- $(git rerere remaining)
         if test $# -eq 0
         then

This cannot be a complete solution. Why do we have another
cd_to_toplevel later, after `git diff --name-only -- "$@"`?

The arguments passed to 'git diff' (including the -O argument) are all 
interpreted as relative to the current working directory, yet 'git diff 
--name-only' outputs pathnames that are relative to the top-level 
directory.  Thus:

   * cd_to_toplevel MUST NOT be run before that 'git diff' command
     unless all pathnames relative to $PWD are converted to absolute (or
     relative to the top-level directory), and
   * cd_to_toplevel MUST be run after 'git diff' so that $files is
     interpreted correctly.

And now I realize that my change breaks -O<foo> if <foo> is relative to 
$PWD.  Grr.  Too bad we don't have tests for running mergetool 
-O<relative-path> from a subdirectory.

Maybe it is necessary to revert back to the flow control that we had
before 57937f70a09c ("mergetool: honor diff.orderFile", 2016-10-07)? It
did not have `test $# -eq 0` and `test -e "$GIT_DIR/MERGE_RR"` in a
single condition.

Reverting to the previous control flow won't work unless the -O pathname 
is converted to absolute (or relative to the top-level directory).  But 
I'll have to do that anyway.  Blech.

Do we already have a helper shell function somewhere that converts a 
pathname to absolute?  Thanks to symlinks it's trickier than one might 
expect.

Thanks,
Richard

-- Hannes