Hi Phillip, On Sun, 17 Jun 2018, Phillip Wood wrote: > On 17/06/18 06:37, Elijah Newren wrote: > > Ever since commit 18633e1a22 ("rebase -i: use the rebase--helper builtin", > > 2017-02-09), when a commit marked as 'reword' in an interactive rebase > > has conflicts and fails to apply, when the rebase is resumed that commit > > will be squashed into its parent with its commit message taken. > > > > The issue can be understood better by looking at commit 56dc3ab04b > > ("sequencer (rebase -i): implement the 'edit' command", 2017-01-02), which > > introduced error_with_patch() for the edit command. For the edit command, > > it needs to stop the rebase whether or not the patch applies cleanly. If > > the patch does apply cleanly, then when it resumes it knows it needs to > > amend all changes into the previous commit. If it does not apply cleanly, > > then the changes should not be amended. Thus, it passes !res (success of > > applying the 'edit' commit) to error_with_patch() for the to_amend flag. > > > > The problematic line of code actually came from commit 04efc8b57c > > ("sequencer (rebase -i): implement the 'reword' command", 2017-01-02). > > Note that to get to this point in the code: > > * !!res (i.e. patch application failed) > > * item->command < TODO_SQUASH > > * item->command != TODO_EDIT > > * !is_fixup(item->command) [i.e. not squash or fixup] > > So that means this can only be a failed patch application that is either a > > pick, revert, or reword. For any of those cases we want a new commit, so > > we should not set the to_amend flag. > > Unfortunately I'm not sure it's that simple. Looking and do_pick() sometimes > reword amends HEAD and sometimes it does not. In the "normal" case then the > commit is picked and committed with '--edit'. However when fast-forwarding the > code fast forwards to the commit to be reworded and then amends it. If the > root commit is being reworded it takes the same code path. While these cases > cannot fail with conflicts, it is possible for the user to cancel the commit > or for them to fail due to collisions with untracked files. > > If I remember correctly the shell version always picks the commit and then > calls 'git commit --amend' afterwards which is less efficient but consistent. > > I'm afraid I don't have a simple solution for fixing this, as currently > pick_commits() does not know if the commit was called with AMEND_MSG, I guess > that means adding some kind of flag for do_pick() to set. Oh, you're right, the fast-forwarding path would pose a problem. I think there is an easy way to resolve this, though: in the case that we do want to amend the to-be-reworded commit, we simply have to see whether HEAD points to the very same commit mentioned in the `reword` command: -- snip -- diff --git a/sequencer.c b/sequencer.c index 2dad7041960..99d33d4e063 100644 --- a/sequencer.c +++ b/sequencer.c @@ -3691,10 +3691,22 @@ static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts) intend_to_amend(); return error_failed_squash(item->commit, opts, item->arg_len, item->arg); - } else if (res && is_rebase_i(opts) && item->commit) + } else if (res && is_rebase_i(opts) && item->commit) { + int to_amend = 0; + + if (item->command == TODO_REWORD) { + struct object_id head; + + if (!get_oid("HEAD", &head) && + !oidcmp(&item->commit->object.oid, + &head)) + to_amend = 1; + } + return res | error_with_patch(item->commit, item->arg, item->arg_len, opts, res, - item->command == TODO_REWORD); + to_amend); + } } else if (item->command == TODO_EXEC) { char *end_of_arg = (char *)(item->arg + item->arg_len); int saved = *end_of_arg; -- snap -- Note that - this patch is only compile-tested, and - it is on top of my sequencer-shears branch thicket, so it might not apply cleanly to master, and - it could probably use a comment what we are doing here (see whether we wanted to amend a fast-forwarded commit). What do you think about this approach? Dscho