Re: [PATCH v3 2/2] rebase-interactive: warn if commit is dropped with `rebase --edit-todo'

[Phillip Wood <phillip.wood123@gmail.com>]

Hi Alban

On 02/12/2019 23:47, Alban Gruin wrote:
 > [...]
> diff --git a/sequencer.c b/sequencer.c
> index 181bb35f5f..75d5ad0496 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -4271,8 +4271,20 @@ int sequencer_continue(struct repository *r, struct replay_opts *opts)
>   	if (read_populate_opts(opts))
>   		return -1;
>   	if (is_rebase_i(opts)) {
> +		struct todo_list backup = TODO_LIST_INIT;
> +
>   		if ((res = read_populate_todo(r, &todo_list, opts)))
>   			goto release_todo_list;
> +
> +		if (strbuf_read_file(&backup.buf, rebase_path_todo_backup(), 0) > 0) {
> +			todo_list_parse_insn_buffer(r, backup.buf.buf, &backup);
> +			res = todo_list_check(&backup, &todo_list);
> +			todo_list_release(&backup);

This causes problems if the user edits the todo list and then later runs 
'git rebase --continue' after resolving conflicts as the backup todo 
list has a bunch of commands that have already been processed but they 
are seen as missing

This test fails

test_expect_success 'rebase.missingCommitsCheck = error after resolving 
conflicts' '
	test_config rebase.missingCommitsCheck error &&
	(
		set_fake_editor &&
		FAKE_LINES="break 2 3 4" git rebase -i A E
	) &&
	git rebase --edit-todo &&
	test_must_fail git rebase --continue &&
	echo x >file1 &&
	git add file1 &&
	git rebase --continue
'

I think it would be better to write a file if the check fails when 
editing the todo list and check for the presence of that file when 
continuing and error out if it exists. This would also allow --edit-todo 
to only remove the backup file if there are no outstanding errors from 
the last edit and so check that those errors are fixed by the second 
edit. I think we'd only want to do this if rebase.missingCommitsCheck is 
set to error.

Best Wishes

Phillip

> +
> +			if (res)
> +				goto release_todo_list;
> +		}
> +
>   		if (commit_staged_changes(r, opts, &todo_list))
>   			return -1;
>   	} else if (!file_exists(get_todo_path(opts)))
> @@ -4986,12 +4998,6 @@ int todo_list_write_to_file(struct repository *r, struct todo_list *todo_list,
>   	return res;
>   }
>   
> -static const char edit_todo_list_advice[] =
> -N_("You can fix this with 'git rebase --edit-todo' "
> -"and then run 'git rebase --continue'.\n"
> -"Or you can abort the rebase with 'git rebase"
> -" --abort'.\n");
> -
>   /* skip picking commits whose parents are unchanged */
>   static int skip_unnecessary_picks(struct repository *r,
>   				  struct todo_list *todo_list,
> @@ -5089,11 +5095,7 @@ int complete_action(struct repository *r, struct replay_opts *opts, unsigned fla
>   		todo_list_release(&new_todo);
>   
>   		return error(_("nothing to do"));
> -	}
> -
> -	if (todo_list_parse_insn_buffer(r, new_todo.buf.buf, &new_todo) ||
> -	    todo_list_check(todo_list, &new_todo)) {
> -		fprintf(stderr, _(edit_todo_list_advice));
> +	} else if (res == -4) {
>   		checkout_onto(r, opts, onto_name, &onto->object.oid, orig_head);
>   		todo_list_release(&new_todo);
>   
> diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
> index 29a35840ed..9051c1e11d 100755
> --- a/t/t3404-rebase-interactive.sh
> +++ b/t/t3404-rebase-interactive.sh
> @@ -1343,6 +1343,89 @@ test_expect_success 'rebase -i respects rebase.missingCommitsCheck = error' '
>   	test B = $(git cat-file commit HEAD^ | sed -ne \$p)
>   '
>   
> +test_expect_success 'rebase --edit-todo respects rebase.missingCommitsCheck = ignore' '
> +	test_config rebase.missingCommitsCheck ignore &&
> +	rebase_setup_and_clean missing-commit &&
> +	set_fake_editor &&
> +	FAKE_LINES="break 1 2 3 4 5" git rebase -i --root &&
> +	FAKE_LINES="1 2 3 4" git rebase --edit-todo 2>actual &&
> +	git rebase --continue 2>actual &&
> +	test D = $(git cat-file commit HEAD | sed -ne \$p) &&
> +	test_i18ngrep \
> +		"Successfully rebased and updated refs/heads/missing-commit" \
> +		actual
> +'
> +
> +test_expect_success 'rebase --edit-todo respects rebase.missingCommitsCheck = warn' '
> +	cat >expect <<-EOF &&
> +	error: invalid line 1: badcmd $(git rev-list --pretty=oneline --abbrev-commit -1 master~4)
> +	Warning: some commits may have been dropped accidentally.
> +	Dropped commits (newer to older):
> +	 - $(git rev-list --pretty=oneline --abbrev-commit -1 master)
> +	To avoid this message, use "drop" to explicitly remove a commit.
> +	EOF
> +	tail -n4 expect >expect.2 &&
> +	test_config rebase.missingCommitsCheck warn &&
> +	rebase_setup_and_clean missing-commit &&
> +	set_fake_editor &&
> +	test_must_fail env FAKE_LINES="bad 1 2 3 4 5" \
> +		git rebase -i --root &&
> +	cp .git/rebase-merge/git-rebase-todo.backup orig &&
> +	FAKE_LINES="2 3 4" git rebase --edit-todo 2>actual.2 &&
> +	head -n5 actual.2 >actual &&
> +	test_i18ncmp expect actual &&
> +	cp orig .git/rebase-merge/git-rebase-todo &&
> +	FAKE_LINES="1 2 3 4" git rebase --edit-todo 2>actual.2 &&
> +	head -n4 actual.2 >actual &&
> +	test_i18ncmp expect.2 actual &&
> +	git rebase --continue 2>actual &&
> +	test D = $(git cat-file commit HEAD | sed -ne \$p) &&
> +	test_i18ngrep \
> +		"Successfully rebased and updated refs/heads/missing-commit" \
> +		actual
> +'
> +
> +test_expect_success 'rebase --edit-todo respects rebase.missingCommitsCheck = error' '
> +	cat >expect <<-EOF &&
> +	error: invalid line 1: badcmd $(git rev-list --pretty=oneline --abbrev-commit -1 master~4)
> +	Warning: some commits may have been dropped accidentally.
> +	Dropped commits (newer to older):
> +	 - $(git rev-list --pretty=oneline --abbrev-commit -1 master)
> +	To avoid this message, use "drop" to explicitly remove a commit.
> +
> +	Use '\''git config rebase.missingCommitsCheck'\'' to change the level of warnings.
> +	The possible behaviours are: ignore, warn, error.
> +
> +	You can fix this with '\''git rebase --edit-todo'\'' and then run '\''git rebase --continue'\''.
> +	Or you can abort the rebase with '\''git rebase --abort'\''.
> +	EOF
> +	tail -n10 expect >expect.2 &&
> +	test_config rebase.missingCommitsCheck error &&
> +	rebase_setup_and_clean missing-commit &&
> +	set_fake_editor &&
> +	test_must_fail env FAKE_LINES="bad 1 2 3 4 5" \
> +		git rebase -i --root &&
> +	cp .git/rebase-merge/git-rebase-todo.backup orig &&
> +	test_must_fail env FAKE_LINES="2 3 4" \
> +		git rebase --edit-todo 2>actual &&
> +	test_i18ncmp expect actual &&
> +	test_must_fail git rebase --continue 2>actual &&
> +	test_i18ncmp expect actual &&
> +	cp orig .git/rebase-merge/git-rebase-todo &&
> +	test_must_fail env FAKE_LINES="1 2 3 4" \
> +		git rebase --edit-todo 2>actual &&
> +	test_i18ncmp expect.2 actual &&
> +	test_must_fail git rebase --continue 2>actual &&
> +	test_i18ncmp expect.2 actual &&
> +	cp orig .git/rebase-merge/git-rebase-todo &&
> +	FAKE_LINES="1 2 3 4 drop 5" git rebase --edit-todo &&
> +	git rebase --continue 2>actual &&
> +	test D = $(git cat-file commit HEAD | sed -ne \$p) &&
> +	test_i18ngrep \
> +		"Successfully rebased and updated refs/heads/missing-commit" \
> +		actual
> +'
> +
>   test_expect_success 'respects rebase.abbreviateCommands with fixup, squash and exec' '
>   	rebase_setup_and_clean abbrevcmd &&
>   	test_commit "first" file1.txt "first line" first &&
>