[PATCH v2] rebase -i: Fix possibly wrong onto hash in todo
From: Antti Keränen <hidden>
Date: 2020-08-13 17:43:21
Subsystem:
the rest · Maintainer:
Linus Torvalds
'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 [off-list ref] Signed-off-by: Antti Keränen <redacted> Acked-by: Alban Gruin <redacted> --- 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