stash: don't delete untracked files that match pathspec

Currently when 'git stash push -- <pathspec>' is used, untracked files
that match the pathspec will be deleted, even though they do not end up
in a stash anywhere.

This is because the original commit introducing the pathspec feature in
git stash push (df6bba0937 ("stash: teach 'push' (and 'create_stash') to
honor pathspec", 2017-02-28)) used the sequence of 'git reset <pathspec>
&& git ls-files --modified <pathspec> | git checkout-index && git clean
<pathspec>'.

The intention was to emulate what 'git reset --hard -- <pathspec>' would
do.  The call to 'git clean' was supposed to clean up the files that
were unstaged by 'git reset'.  This would work fine if the pathspec
doesn't match any files that were untracked before 'git stash push --
<pathspec>'.  However if <pathspec> matches a file that was untracked
before invoking the 'stash' command, all untracked files matching the
pathspec would inadvertently be deleted as well, even though they
wouldn't end up in the stash, and are therefore lost.

This behaviour was never what was intended, only blobs that also end up
in the stash should be reset to their state in HEAD, previously
untracked files should be left alone.

To achieve this, first match what's in the index and what's in the
working tree by adding all changes to the index, ask diff-index what
changed between HEAD and the current index, and then apply that patch in
reverse to get rid of the changes, which includes removal of added
files and resurrection of removed files.

Reported-by: Reid Price <reid.price@gmail.com>
Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-stash.sh b/git-stash.sh
index 8b2ce9afdab6d67e8b9af5fc97a30dc6941323f2..b48b16474865bb9540c0fa108299d77b2f00ecbb 100755 (executable)
--- a/git-stash.sh
+++ b/git-stash.sh
@@ -315,10 +315,9 @@ push_stash () {
 
                if test $# != 0
                then
-                       git reset -q -- "$@"
-                       git ls-files -z --modified -- "$@" |
+                       git add -u -- "$@" |
                        git checkout-index -z --force --stdin
-                       git clean --force -q -d -- "$@"
+                       git diff-index -p --cached --binary HEAD -- "$@" | git apply --index -R
                else
                        git reset --hard -q
                fi

diff --git a/t/t3903-stash.sh b/t/t3903-stash.sh
index 3b1ac1971af1d972b77b3dfe8ae4a56e00e1fa55..1cd85e70e90d6796c75a94ce73606ef691c4e483 100755 (executable)
--- a/t/t3903-stash.sh
+++ b/t/t3903-stash.sh
@@ -971,4 +971,36 @@ test_expect_success 'stash -k -- <pathspec> leaves unstaged files intact' '
        test foo,bar = $(cat foo),$(cat bar)
 '
 
+test_expect_success 'stash -- <subdir> leaves untracked files in subdir intact' '
+       git reset &&
+       >subdir/untracked &&
+       >subdir/tracked1 &&
+       >subdir/tracked2 &&
+       git add subdir/tracked* &&
+       git stash -- subdir/ &&
+       test_path_is_missing subdir/tracked1 &&
+       test_path_is_missing subdir/tracked2 &&
+       test_path_is_file subdir/untracked &&
+       git stash pop &&
+       test_path_is_file subdir/tracked1 &&
+       test_path_is_file subdir/tracked2 &&
+       test_path_is_file subdir/untracked
+'
+
+test_expect_success 'stash -- <subdir> works with binary files' '
+       git reset &&
+       >subdir/untracked &&
+       >subdir/tracked &&
+       cp "$TEST_DIRECTORY"/test-binary-1.png subdir/tracked-binary &&
+       git add subdir/tracked* &&
+       git stash -- subdir/ &&
+       test_path_is_missing subdir/tracked &&
+       test_path_is_missing subdir/tracked-binary &&
+       test_path_is_file subdir/untracked &&
+       git stash pop &&
+       test_path_is_file subdir/tracked &&
+       test_path_is_file subdir/tracked-binary &&
+       test_path_is_file subdir/untracked
+'
+
 test_done