rebase -p -i: handle "no changes" gracefully

Since commit 376ccb8cbb453343998e734d8a1ce79f57a4e092 (rebase -i: style
fixes and minor cleanups), unchanged SHA-1s are no longer mapped via
$REWRITTEN.  But the updating phase was not prepared for the old head
not being rewritten.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index f83e00f..cd7e43f 100755 (executable)
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -322,7 +322,12 @@ do_next () {
                test -f "$DOTEST"/current-commit &&
                        current_commit=$(cat "$DOTEST"/current-commit) &&
                        git rev-parse HEAD > "$REWRITTEN"/$current_commit
-               NEWHEAD=$(cat "$REWRITTEN"/$OLDHEAD)
+               if test -f "$REWRITTEN"/$OLDHEAD
+               then
+                       NEWHEAD=$(cat "$REWRITTEN"/$OLDHEAD)
+               else
+                       NEWHEAD=$OLDHEAD
+               fi
        else
                NEWHEAD=$(git rev-parse HEAD)
        fi &&

diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 907c7f9..74a7eb3 100755 (executable)
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -184,6 +184,12 @@ test_expect_success 'retain authorship when squashing' '
        git show HEAD | grep "^Author: Twerp Snog"
 '
 
+test_expect_success '-p handles "no changes" gracefully' '
+       HEAD=$(git rev-parse HEAD) &&
+       git rebase -i -p HEAD^ &&
+       test $HEAD = $(git rev-parse HEAD)
+'
+
 test_expect_success 'preserve merges with -p' '
        git checkout -b to-be-preserved master^ &&
        : > unrelated-file &&