Triggered by one of brian's SHA-256 patch series, I looked at the reason why the SHA-1 collision test case passed when it shouldn't. Turns out that the regression test was not quite thorough enough, and the interactive rebase did regress recently. While in the area, I realized that the same bug exists in the code backing the rebase.missingCommitsCheck feature: the backed-up todo list uses shortened commit IDs that may very well become ambiguous during the rebase. For good measure, this patch series fixes that, too. Finally, I saw that git rebase --edit-todo reported the line in an awkward, maybe even incorrect, way when there was an ambiguous commit ID, and I also fixed that. To make sure that the code can be easily adapted to SHA-256 after these patches, I actually already made those adjustments on top and offered them up at https://github.com/bk2204/git/pull/1. Changes since v2: * Clarified in the first commit message that the change from a positive return value to a negative return value (to indicate failure, in both cases) both was intentional, and does not require any change in the corresponding function's only caller. Changes since v1: * Turned the error condition when parsing the todo list with just-expanded commit IDs failed into a BUG(). Johannes Schindelin (3): parse_insn_line(): improve error message when parsing failed rebase -i: re-fix short SHA-1 collision rebase -i: also avoid SHA-1 collisions with missingCommitsCheck rebase-interactive.c | 8 +++++--- sequencer.c | 18 ++++++++++++++---- t/t3404-rebase-interactive.sh | 17 +++++++++++++++-- 3 files changed, 34 insertions(+), 9 deletions(-) base-commit: d0654dc308b0ba76dd8ed7bbb33c8d8f7aacd783 Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-529%2Fdscho%2Fre-fix-rebase-i-with-sha-collisions-v3 Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-529/dscho/re-fix-rebase-i-with-sha-collisions-v3 Pull-Request: https://github.com/gitgitgadget/git/pull/529 Range-diff vs v2: 1: 2ae2e435b0 ! 1: 6f5c7b0325 parse_insn_line(): improve error message when parsing failed @@ -7,6 +7,11 @@ That makes it rather hard for users to understand what is going wrong, so let's fix that. + While at it, return a negative value from `parse_insn_line()` in case of + an error, as per our convention. This function's only caller, + `todo_list_parse_insn_buffer()`, cares only whether that return value is + non-zero or not, i.e. does not need to be changed. + Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx> diff --git a/sequencer.c b/sequencer.c 2: 102fa568dc = 2: 595ba81e09 rebase -i: re-fix short SHA-1 collision 3: 486e9413a6 = 3: b7b063408f rebase -i: also avoid SHA-1 collisions with missingCommitsCheck -- gitgitgadget