Re: [PATCH v2] sequencer: do not squash 'reword' commits when we hit conflicts

> 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.
> 
> Signed-off-by: Elijah Newren <newren@gmail.com>
> ---
> Differences since v1 (Thanks to Eric Sunshine for the suggestions):
>   * Add test_when_finished "reset_rebase" calls
>   * Remove unnecessary word from description of test
> 
>  sequencer.c              |  2 +-
>  t/t3423-rebase-reword.sh | 48 ++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 49 insertions(+), 1 deletion(-)
>  create mode 100755 t/t3423-rebase-reword.sh
> 
> diff --git a/sequencer.c b/sequencer.c
> index cca968043e..9e6d1ee368 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -3217,7 +3217,7 @@ static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts)
>  			} else if (res && is_rebase_i(opts) && item->commit)
>  				return res | error_with_patch(item->commit,
>  					item->arg, item->arg_len, opts, res,
> -					item->command == TODO_REWORD);
> +					0);