Re: [GSoC][PATCH v3 2/3] cherry-pick/revert: add --skip option

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

Hi Rohit

This is definitely moving in the right direction.

On 13/06/2019 05:05, Rohit Ashiwal wrote:
> git am or rebase have a --skip flag to skip the current commit if the
> user wishes to do so. During a cherry-pick or revert a user could
> likewise skip a commit, but needs to use 'git reset' (or in the case
> of conflicts 'git reset --merge'), followed by 'git (cherry-pick |
> revert) --continue' to skip the commit. This is more annoying and
> sometimes confusing on the users' part. Add a `--skip` option to make
> skipping commits easier for the user and to make the commands more
> consistent.
> 
> In the next commit, we will change the advice messages and some tests
> hence finishing the process of teaching revert and cherry-pick
> "how to skip commits".
> 
> Signed-off-by: Rohit Ashiwal <rohit.ashiwal265@gmail.com>
> ---
> changes:
>     - Remove `reset_merge` from last revision[1] and modified `reset_for_rollback`
>       and signature of `rollback_single_pick` to handle if `--skip` flag
>     - Modify test which gave "ambiguous refname" warning[2]
> 
> [1]: https://public-inbox.org/git/20190608191958.4593-1-rohit.ashiwal265@gmail.com/T/#m11a573a3b91dfd2fcfae40c6ecc2148f8c92e10c
> [2]: https://public-inbox.org/git/20190608191958.4593-1-rohit.ashiwal265@gmail.com/T/#m586cb8930cfcb737e4f19662f0eef3716b1e9d35
> 
>  Documentation/git-cherry-pick.txt |   4 +-
>  Documentation/git-revert.txt      |   4 +-
>  Documentation/sequencer.txt       |   4 ++
>  builtin/revert.c                  |   5 ++
>  sequencer.c                       |  67 +++++++++++++++++---
>  sequencer.h                       |   1 +
>  t/t3510-cherry-pick-sequence.sh   | 102 ++++++++++++++++++++++++++++++
>  7 files changed, 171 insertions(+), 16 deletions(-)
> 
> diff --git a/Documentation/git-cherry-pick.txt b/Documentation/git-cherry-pick.txt
> index 754b16ce0c..955880ab88 100644
> --- a/Documentation/git-cherry-pick.txt
> +++ b/Documentation/git-cherry-pick.txt
> @@ -10,9 +10,7 @@ SYNOPSIS
>  [verse]
>  'git cherry-pick' [--edit] [-n] [-m parent-number] [-s] [-x] [--ff]
>  		  [-S[<keyid>]] <commit>...
> -'git cherry-pick' --continue
> -'git cherry-pick' --quit
> -'git cherry-pick' --abort
> +'git cherry-pick' --continue | --skip | --abort | --quit
>  
>  DESCRIPTION
>  -----------
> diff --git a/Documentation/git-revert.txt b/Documentation/git-revert.txt
> index 0c82ca5bc0..ffce98099c 100644
> --- a/Documentation/git-revert.txt
> +++ b/Documentation/git-revert.txt
> @@ -9,9 +9,7 @@ SYNOPSIS
>  --------
>  [verse]
>  'git revert' [--[no-]edit] [-n] [-m parent-number] [-s] [-S[<keyid>]] <commit>...
> -'git revert' --continue
> -'git revert' --quit
> -'git revert' --abort
> +'git revert' --continue | --skip | --abort | --quit
>  
>  DESCRIPTION
>  -----------
> diff --git a/Documentation/sequencer.txt b/Documentation/sequencer.txt
> index 5a57c4a407..3bceb56474 100644
> --- a/Documentation/sequencer.txt
> +++ b/Documentation/sequencer.txt
> @@ -3,6 +3,10 @@
>  	`.git/sequencer`.  Can be used to continue after resolving
>  	conflicts in a failed cherry-pick or revert.
>  
> +--skip::
> +	Skip the current commit and continue with the rest of the
> +	sequence.
> +
>  --quit::
>  	Forget about the current operation in progress.  Can be used
>  	to clear the sequencer state after a failed cherry-pick or
> diff --git a/builtin/revert.c b/builtin/revert.c
> index d4dcedbdc6..5dc5891ea2 100644
> --- a/builtin/revert.c
> +++ b/builtin/revert.c
> @@ -102,6 +102,7 @@ static int run_sequencer(int argc, const char **argv, struct replay_opts *opts)
>  		OPT_CMDMODE(0, "quit", &cmd, N_("end revert or cherry-pick sequence"), 'q'),
>  		OPT_CMDMODE(0, "continue", &cmd, N_("resume revert or cherry-pick sequence"), 'c'),
>  		OPT_CMDMODE(0, "abort", &cmd, N_("cancel revert or cherry-pick sequence"), 'a'),
> +		OPT_CMDMODE(0, "skip", &cmd, N_("skip current commit and continue"), 's'),
>  		OPT_CLEANUP(&cleanup_arg),
>  		OPT_BOOL('n', "no-commit", &opts->no_commit, N_("don't automatically commit")),
>  		OPT_BOOL('e', "edit", &opts->edit, N_("edit the commit message")),
> @@ -151,6 +152,8 @@ static int run_sequencer(int argc, const char **argv, struct replay_opts *opts)
>  			this_operation = "--quit";
>  		else if (cmd == 'c')
>  			this_operation = "--continue";
> +		else if (cmd == 's')
> +			this_operation = "--skip";
>  		else {
>  			assert(cmd == 'a');
>  			this_operation = "--abort";
> @@ -210,6 +213,8 @@ static int run_sequencer(int argc, const char **argv, struct replay_opts *opts)
>  		return sequencer_continue(the_repository, opts);
>  	if (cmd == 'a')
>  		return sequencer_rollback(the_repository, opts);
> +	if (cmd == 's')
> +		return sequencer_skip(the_repository, opts);
>  	return sequencer_pick_revisions(the_repository, opts);
>  }
>  
> diff --git a/sequencer.c b/sequencer.c
> index 918cb5d761..6b78a26920 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -2733,25 +2733,26 @@ static int rollback_is_safe(void)
>  
>  static int reset_for_rollback(const struct object_id *oid)
>  {
> -	const char *argv[4];	/* reset --merge <arg> + NULL */
> +	struct argv_array argv = ARGV_ARRAY_INIT;	/* reset --merge <arg> + NULL */
>  
> -	argv[0] = "reset";
> -	argv[1] = "--merge";
> -	argv[2] = oid_to_hex(oid);
> -	argv[3] = NULL;
> -	return run_command_v_opt(argv, RUN_GIT_CMD);
> +	argv_array_pushl(&argv, "reset", "--merge", NULL);
> +
> +	if (!is_null_oid(oid))
> +		argv_array_push(&argv, oid_to_hex(oid));
> +

argv_array_pushl() copies the strings so you need to call
argv_array_clear() when you're done with it.

> +	return run_command_v_opt(argv.argv, RUN_GIT_CMD);>  }
>  
> -static int rollback_single_pick(struct repository *r)
> +static int rollback_single_pick(struct repository *r, unsigned int is_skip)
>  {
>  	struct object_id head_oid;
>  
>  	if (!file_exists(git_path_cherry_pick_head(r)) &&
> -	    !file_exists(git_path_revert_head(r)))
> +	    !file_exists(git_path_revert_head(r)) && !is_skip)
>  		return error(_("no cherry-pick or revert in progress"));
>  	if (read_ref_full("HEAD", 0, &head_oid, NULL))
>  		return error(_("cannot resolve HEAD"));
> -	if (is_null_oid(&head_oid))
> +	if (is_null_oid(&head_oid) && !is_skip)
>  		return error(_("cannot abort from a branch yet to be born"));

The changes here look good. One thing though - this still does not check
if we're on the final pick or not. The more I think about it the more I
think it shouldn't matter but I'm bothered about why abort refuses to
run on the null oid. I've cc'd Jonathan in case he can remember why this
code is here. I looked at the discussion [1] of the patch [2] that
introduced this but that bit doesn't seem to have been discussed.

[1]
https://public-inbox.org/git/20111211195836.GA25482@elie.hsd1.il.comcast.net/T/#u

[2]
https://github.com/git/git/commit/539047c19ec040819b6f6af2d55714195b812abb

>  	return reset_for_rollback(&head_oid);
>  }
> @@ -2770,7 +2771,7 @@ int sequencer_rollback(struct repository *r, struct replay_opts *opts)
>  		 * If CHERRY_PICK_HEAD or REVERT_HEAD indicates
>  		 * a single-cherry-pick in progress, abort that.
>  		 */
> -		return rollback_single_pick(r);
> +		return rollback_single_pick(r, 0);
>  	}
>  	if (!f)
>  		return error_errno(_("cannot open '%s'"), git_path_head_file());
> @@ -2805,6 +2806,52 @@ int sequencer_rollback(struct repository *r, struct replay_opts *opts)
>  	return -1;
>  }
>  
> +int sequencer_skip(struct repository *r, struct replay_opts *opts)
> +{
> +	enum replay_action action = -1;
> +	sequencer_get_last_command(r, &action);
> +
> +	switch (opts->action) {
> +	case REPLAY_REVERT:
> +		if (!file_exists(git_path_revert_head(r))) {
> +			if (action == REPLAY_REVERT) {
> +				if (!rollback_is_safe())
> +					goto give_advice;
> +				else
> +					break;
> +			}
> +			return error(_("no revert in progress"));
> +		}
> +		break;
> +	case REPLAY_PICK:
> +		if (!file_exists(git_path_cherry_pick_head(r))) {
> +			if (action == REPLAY_PICK) {
> +				if (!rollback_is_safe())
> +					goto give_advice;
> +				else
> +					break;
> +			}
> +			return error(_("no cherry-pick in progress"));
> +		}
> +		break;
> +	default:
> +		BUG("the control must not reach here");
> +	}
> +
> +	if (rollback_single_pick(r, 1))
> +		return error(_("failed to skip the commit"));
> +	if (!is_directory(git_path_seq_dir()))
> +		return 0;
> +
> +	return sequencer_continue(r, opts);
> +
> +give_advice:
> +	advise(_("have you committed already?\n"
> +		 "try \"git %s --continue\""),
> +		 action == REPLAY_REVERT ? "revert" : "cherry-pick");
> +	return error(_("there is nothing to skip"));
> +}
> +
>  static int save_todo(struct todo_list *todo_list, struct replay_opts *opts)
>  {
>  	struct lock_file todo_lock = LOCK_INIT;
> diff --git a/sequencer.h b/sequencer.h
> index 0c494b83d4..731b9853eb 100644
> --- a/sequencer.h
> +++ b/sequencer.h
> @@ -129,6 +129,7 @@ int sequencer_pick_revisions(struct repository *repo,
>  			     struct replay_opts *opts);
>  int sequencer_continue(struct repository *repo, struct replay_opts *opts);
>  int sequencer_rollback(struct repository *repo, struct replay_opts *opts);
> +int sequencer_skip(struct repository *repo, struct replay_opts *opts);
>  int sequencer_remove_state(struct replay_opts *opts);
>  
>  #define TODO_LIST_KEEP_EMPTY (1U << 0)
> diff --git a/t/t3510-cherry-pick-sequence.sh b/t/t3510-cherry-pick-sequence.sh
> index 941d5026da..f85ef51cac 100755
> --- a/t/t3510-cherry-pick-sequence.sh
> +++ b/t/t3510-cherry-pick-sequence.sh
> @@ -93,6 +93,108 @@ test_expect_success 'cherry-pick cleans up sequencer state upon success' '
>  	test_path_is_missing .git/sequencer
>  '
>  
> +test_expect_success 'cherry-pick --skip requires cherry-pick in progress' '
> +	pristine_detach initial &&
> +	test_must_fail git cherry-pick --skip
> +'
> +
> +test_expect_success 'revert --skip requires revert in progress' '
> +	pristine_detach initial &&
> +	test_must_fail git revert --skip
> +'
> +
> +test_expect_success 'cherry-pick --skip to skip commit' '
> +	pristine_detach initial &&
> +	test_must_fail git cherry-pick anotherpick &&
> +	test_must_fail git revert --skip &&
> +	git cherry-pick --skip &&
> +	test_cmp_rev initial HEAD &&
> +	test_path_is_missing .git/CHERRY_PICK_HEAD
> +'
> +
> +test_expect_success 'revert --skip to skip commit' '
> +	pristine_detach anotherpick &&
> +	test_must_fail git revert anotherpick~1 &&
> +	test_must_fail git cherry-pick --skip &&
> +	git revert --skip &&
> +	test_cmp_rev anotherpick HEAD
> +'
> +
> +test_expect_success 'skip "empty" commit' '
> +	pristine_detach picked &&
> +	test_commit dummy foo d &&
> +	test_must_fail git cherry-pick anotherpick &&
> +	git cherry-pick --skip &&
> +	test_cmp_rev dummy HEAD
> +'
> +
> +test_expect_success 'skip a commit and check if rest of sequence is correct' '
> +	pristine_detach initial &&
> +	echo e >expect &&
> +	cat >expect.log <<-EOF &&
> +	OBJID
> +	:100644 100644 OBJID OBJID M	foo
> +	OBJID
> +	:100644 100644 OBJID OBJID M	foo
> +	OBJID
> +	:100644 100644 OBJID OBJID M	unrelated
> +	OBJID
> +	:000000 100644 OBJID OBJID A	foo
> +	:000000 100644 OBJID OBJID A	unrelated
> +	EOF
> +	test_must_fail git cherry-pick base..yetanotherpick &&
> +	test_must_fail git cherry-pick --skip &&
> +	echo d >foo &&
> +	git add foo &&
> +	git cherry-pick --continue &&
> +	{
> +		git rev-list HEAD |
> +		git diff-tree --root --stdin |
> +		sed "s/$OID_REGEX/OBJID/g"
> +	} >actual.log &&
> +	test_cmp expect foo &&
> +	test_cmp expect.log actual.log
> +'
> +
> +test_expect_success 'check advice when we move HEAD by committing' '
> +	pristine_detach initial &&
> +	cat >expect <<-EOF &&
> +	hint: have you committed already?
> +	hint: try "git cherry-pick --continue"
> +	error: there is nothing to skip
> +	fatal: cherry-pick failed
> +	EOF
> +	test_must_fail git cherry-pick base..yetanotherpick &&
> +	echo c >foo &&
> +	git commit -a &&
> +	test_path_is_missing .git/CHERRY_PICK_HEAD &&
> +	test_must_fail git cherry-pick --skip 2>advice &&
> +	test_cmp expect advice

When you compare a translated string you need to use test_i18ncmp to
avoid test breakages when running under GET_TEXT_POISON. The CI suite
shows this up [3]. There are instructions for running tests under travis
in Documentation/SubmittingPatches.txt or Johannes can advise you about
using his CI setup with pull requests on gitgitgadget (and maybe git.git?)

Best Wishes

Phillip


[3] https://travis-ci.org/phillipwood/git/jobs/545251777

> +'
> +
> +test_expect_success 'allow skipping commit but not abort for a new history' '
> +	pristine_detach initial &&
> +	cat >expect <<-EOF &&
> +	error: cannot abort from a branch yet to be born
> +	fatal: cherry-pick failed
> +	EOF
> +	git checkout --orphan new_disconnected &&
> +	git reset --hard &&
> +	test_must_fail git cherry-pick anotherpick &&
> +	test_must_fail git cherry-pick --abort 2>advice &&
> +	git cherry-pick --skip &&
> +	test_cmp expect advice
> +'
> +
> +test_expect_success 'allow skipping stopped cherry-pick because of untracked file modifications' '
> +	pristine_detach initial &&
> +	git rm --cached unrelated &&
> +	git commit -m "untrack unrelated" &&
> +	test_must_fail git cherry-pick initial base &&
> +	test_path_is_missing .git/CHERRY_PICK_HEAD &&
> +	git cherry-pick --skip
> +'
> +
>  test_expect_success '--quit does not complain when no cherry-pick is in progress' '
>  	pristine_detach initial &&
>  	git cherry-pick --quit
>