'todo_list_write_to_file' may overwrite the static buffer, originating
from 'find_unique_abbrev', that was used to store the short commit hash
'c' for "# Rebase a..b onto c" message in the todo editor. This is
because the buffer that is returned from 'find_unique_abbrev' is valid
until 4 more calls to `find_unique_abbrev` are made.
As 'todo_list_write_to_file' calls 'find_unique_abbrev' for each rebased
commit, the hash for 'c' is overwritten if there are 4 or more commits
in the rebase. This behavior has been broken since its introduction.
Fix by storing the short onto commit hash in a different buffer that
remains valid, before calling 'todo_list_write_to_file'.
Found-by: Jussi Keränen <jussike@xxxxxxxxx>
Signed-off-by: Antti Keränen <detegr@rbx.email>
Acked-by: Alban Gruin <alban.gruin@xxxxxxxxx>
---
sequencer.c | 5 +++--
t/t3404-rebase-interactive.sh | 6 ++++++
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/sequencer.c b/sequencer.c
index fd7701c88a..e2007dbb8c 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -5178,13 +5178,14 @@ int complete_action(struct repository *r, struct replay_opts *opts, unsigned fla
struct string_list *commands, unsigned autosquash,
struct todo_list *todo_list)
{
- const char *shortonto, *todo_file = rebase_path_todo();
+ char shortonto[GIT_MAX_HEXSZ + 1];
+ const char *todo_file = rebase_path_todo();
struct todo_list new_todo = TODO_LIST_INIT;
struct strbuf *buf = &todo_list->buf, buf2 = STRBUF_INIT;
struct object_id oid = onto->object.oid;
int res;
- shortonto = find_unique_abbrev(&oid, DEFAULT_ABBREV);
+ find_unique_abbrev_r(shortonto, &oid, DEFAULT_ABBREV);
if (buf->len == 0) {
struct todo_item *item = append_new_todo(todo_list);
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 4a7d21f898..1b4fa0843e 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -1760,6 +1760,12 @@ test_expect_success 'correct error message for commit --amend after empty pick'
test_i18ngrep "middle of a rebase -- cannot amend." err
'
+test_expect_success 'todo has correct onto hash' '
+ GIT_SEQUENCE_EDITOR=cat git rebase -i no-conflict-branch~4 no-conflict-branch >actual &&
+ onto=$(git rev-parse --short HEAD~4) &&
+ test_i18ngrep "^# Rebase ..* onto $onto" actual
+'
+
# This must be the last test in this file
test_expect_success '$EDITOR and friends are unchanged' '
test_editor_unchanged
--
2.27.0.395.g84249cff14
