From: Phillip Wood <phillip.wood@xxxxxxxxxxxxx> After rebasing, ORIG_HEAD is supposed to point to the old HEAD of the rebased branch. The code used find_unique_abbrev() to obtain the object name of the old HEAD and wrote to both .git/rebase-merge/orig-head (used by `rebase --abort` to go back to the previous state) and to ORIG_HEAD. The buffer find_unique_abbrev() gives back is volatile, unfortunately, and was overwritten after the former file is written but before ORIG_FILE is written, leaving an incorrect object name in it. Avoid relying on the volatile buffer of find_unique_abbrev(), and instead supply our own buffer to keep the object name. I think that all of the users of head_hash should actually be using opts->orig_head instead as passing a string rather than a struct object_id around is a hang over from the scripted implementation. This patch just fixes the immediate bug and adds a regression test based on Caspar's reproduction example[1]. The users will be converted to use struct object_id and head_hash removed in the next few commits. [1] https://lore.kernel.org/git/CAFzd1+7PDg2PZgKw7U0kdepdYuoML9wSN4kofmB_-8NHrbbrHg@xxxxxxxxxxxxxx Reported-by: Caspar Duregger <herr.kaste@xxxxxxxxx> Signed-off-by: Phillip Wood <phillip.wood@xxxxxxxxxxxxx> --- builtin/rebase.c | 10 +++++----- t/t3404-rebase-interactive.sh | 11 +++++++++++ 2 files changed, 16 insertions(+), 5 deletions(-) diff --git a/builtin/rebase.c b/builtin/rebase.c index eeca53382f..cd101b2559 100644 --- a/builtin/rebase.c +++ b/builtin/rebase.c @@ -270,15 +270,15 @@ static int edit_todo_file(unsigned flags) } static int get_revision_ranges(struct commit *upstream, struct commit *onto, - struct object_id *orig_head, const char **head_hash, + struct object_id *orig_head, char *head_hash, char **revisions, char **shortrevisions) { struct commit *base_rev = upstream ? upstream : onto; const char *shorthead; - *head_hash = find_unique_abbrev(orig_head, GIT_MAX_HEXSZ); + find_unique_abbrev_r(head_hash, orig_head, GIT_MAX_HEXSZ); *revisions = xstrfmt("%s...%s", oid_to_hex(&base_rev->object.oid), - *head_hash); + head_hash); shorthead = find_unique_abbrev(orig_head, DEFAULT_ABBREV); @@ -327,7 +327,7 @@ static void split_exec_commands(const char *cmd, struct string_list *commands) static int do_interactive_rebase(struct rebase_options *opts, unsigned flags) { int ret; - const char *head_hash = NULL; + char head_hash[GIT_MAX_HEXSZ]; char *revisions = NULL, *shortrevisions = NULL; struct strvec make_script_args = STRVEC_INIT; struct todo_list todo_list = TODO_LIST_INIT; @@ -335,7 +335,7 @@ static int do_interactive_rebase(struct rebase_options *opts, unsigned flags) struct string_list commands = STRING_LIST_INIT_DUP; if (get_revision_ranges(opts->upstream, opts->onto, &opts->orig_head, - &head_hash, &revisions, &shortrevisions)) + head_hash, &revisions, &shortrevisions)) return -1; if (init_basic_state(&replay, diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh index 07a1617351..1e56696e4f 100755 --- a/t/t3404-rebase-interactive.sh +++ b/t/t3404-rebase-interactive.sh @@ -1797,6 +1797,17 @@ test_expect_success 'todo has correct onto hash' ' test_i18ngrep "^# Rebase ..* onto $onto" actual ' +test_expect_success 'ORIG_HEAD is updated correctly' ' + test_when_finished "git checkout master && git branch -D test-orig-head" && + git checkout -b test-orig-head A && + git commit --allow-empty -m A1 && + git commit --allow-empty -m A2 && + git commit --allow-empty -m A3 && + git commit --allow-empty -m A4 && + git rebase master && + test_cmp_rev ORIG_HEAD test-orig-head@{1} +' + # This must be the last test in this file test_expect_success '$EDITOR and friends are unchanged' ' test_editor_unchanged -- gitgitgadget
