In 0041797449 (vimdiff: new implementation with layout support,
2022-03-30), we introduced a completely new implementation of the
`vimdiff` backend for `git mergetool`.
In this implementation, we no longer call `vim` directly but we
accumulate in the variable `FINAL_CMD` an arbitrary number of commands
for `vim` to execute, which necessitates the use of `eval` to split the
commands properly into multiple command-line arguments.
That same `eval` command also needs to pass the paths to `vim`, and
while it looks as if they are quoted correctly, that quoting only
reaches the `eval` instruction and is lost after that, therefore paths
that contain whitespace characters (or other characters that are
interpreted by the POSIX shell) are handled incorrectly.
This is a simple reproducer:
git init -b main bam-merge-fail
cd bam-merge-fail
echo a>"a file.txt"
git add "a file.txt"
git commit -m "added 'a file.txt'"
echo b>"a file.txt"
git add "a file.txt"
git commit -m "diverged b 'a file.txt'"
git checkout -b c HEAD~
echo c>"a file.txt"
git add "a file.txt"
git commit -m "diverged c 'a file.txt'"
git checkout main
git merge c
git mergetool --tool=vimdiff
With Git v2.37.0/v2.37.1, this will open 7 buffers, not four, and not
display the correct contents at all.
To fix this, let's not expand the variables containing the path
parameters before passing them to the `eval` command, but let that
command expand the variables instead.
This fixes https://github.com/git-for-windows/git/issues/3945
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
ccc7b5148b