Re: [PATCH v3 2/2] worktree add: add --orphan flag

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

On Sat, Nov 19 2022, Jacob Abel wrote:

> On 22/11/15 11:09PM, Ævar Arnfjörð Bjarmason wrote:
>>
>> On Thu, Nov 10 2022, Jacob Abel wrote:
>>
>> So, on a second read-through...
>>
>> >  'git worktree add' [-f] [--detach] [--checkout] [--lock [--reason <string>]]
>> > -		   [[-b | -B] <new-branch>] <path> [<commit-ish>]
>> > +		   [[-b | -B | --orphan] <new-branch>] <path> [<commit-ish>]
>>
>> This synopsis is now at least partially wrong, and ....
>>
>> > +--orphan <new-branch>::
>> > +	With `add`, create a new orphan branch named `<new-branch>` in the new
>> > +	worktree. See `--orphan` in linkgit:git-switch[1] for details.
>> > +
>> >  --porcelain::
>> > ....
>> >  #define BUILTIN_WORKTREE_ADD_USAGE \
>> >  	N_("git worktree add [-f] [--detach] [--checkout] [--lock [--reason <string>]]\n" \
>> > -	   "                 [[-b | -B] <new-branch>] <path> [<commit-ish>]")
>> > +	   "                 [[-b | -B | --orphan] <new-branch>] <path> [<commit-ish>]")
>>
>>
>> ...here we say the same, but surely it's only:
>>
>> 	git worktree add --orphan new-branch /tmp/orphan
>>
>> And not e.g.:
>>
>> 	git worktree add --orphan new-branch /tmp/orphan origin/next
>>
>> Or whatever, but it's incompatible with <commit-ish>. I think this on
>> top should fix it up:
>>
>> 	diff --git a/Documentation/git-worktree.txt b/Documentation/git-worktree.txt
>> 	index 1310bfb564f..3afef985154 100644
>> 	--- a/Documentation/git-worktree.txt
>> 	+++ b/Documentation/git-worktree.txt
>> 	@@ -10,7 +10,9 @@ SYNOPSIS
>> 	 --------
>> 	 [verse]
>> 	 'git worktree add' [-f] [--detach] [--checkout] [--lock [--reason <string>]]
>> 	-		   [[-b | -B | --orphan] <new-branch>] <path> [<commit-ish>]
>> 	+		   [[-b | -B] <new-branch>] <path> [<commit-ish>]
>> 	+'git worktree add' [-f] [--lock [--reason <string>]]
>> 	+		   --orphan <new-branch> <path>
>> 	 'git worktree list' [-v | --porcelain [-z]]
>> 	 'git worktree lock' [--reason <string>] <worktree>
>> 	 'git worktree move' <worktree> <new-path>
>> 	diff --git a/builtin/worktree.c b/builtin/worktree.c
>> 	index 71786b72f6b..2b811630b3a 100644
>> 	--- a/builtin/worktree.c
>> 	+++ b/builtin/worktree.c
>> 	@@ -17,7 +17,10 @@
>>
>> 	 #define BUILTIN_WORKTREE_ADD_USAGE \
>> 	 	N_("git worktree add [-f] [--detach] [--checkout] [--lock [--reason <string>]]\n" \
>> 	-	   "                 [[-b | -B | --orphan] <new-branch>] <path> [<commit-ish>]")
>> 	+	   "                 [[-b | -B] <new-branch>] <path> [<commit-ish>]"), \
>> 	+	N_("git worktree add [-f] [--lock [--reason <string>]]\n" \
>> 	+	   "                 --orphan <new-branch> <path>")
>> 	+
>> 	 #define BUILTIN_WORKTREE_LIST_USAGE \
>> 	 	N_("git worktree list [-v | --porcelain [-z]]")
>> 	 #define BUILTIN_WORKTREE_LOCK_USAGE \
>> 	@@ -668,6 +671,9 @@ static int add(int ac, const char **av, const char *prefix)
>> 	 	if (opts.orphan_branch && !opts.checkout)
>> 	 		die(_("'%s' and '%s' cannot be used together"), "--orphan",
>> 	 		    "--no-checkout");
>> 	+	if (opts.orphan_branch && ac == 2)
>> 	+		die(_("'%s' and '%s' cannot be used together"), "--orphan",
>> 	+		    _("<commit-ish>"));
>> 	 	if (lock_reason && !keep_locked)
>> 	 		die(_("the option '%s' requires '%s'"), "--reason", "--lock");
>> 	 	if (lock_reason)
>> 	diff --git a/t/t2400-worktree-add.sh b/t/t2400-worktree-add.sh
>> 	index 93c340f4aff..47461d02115 100755
>> 	--- a/t/t2400-worktree-add.sh
>> 	+++ b/t/t2400-worktree-add.sh
>> 	@@ -326,6 +326,10 @@ test_expect_success '"add" --orphan/--no-checkout mutually exclusive' '
>> 	 	test_must_fail git worktree add --orphan poodle --no-checkout bamboo
>> 	 '
>>
>> 	+test_expect_success '"add" --orphan and <commit-ish> mutually exclusive' '
>> 	+	test_must_fail git worktree add --orphan poodle bamboo main
>> 	+'
>> 	+
>> 	 test_expect_success '"add" -B/--detach mutually exclusive' '
>> 	 	test_must_fail git worktree add -B poodle --detach bamboo main
>> 	 '
>
> Yep, you are right. I applied the patch as part of this 2/2 patch and will
> include it in v4. When it comes to attribution, is there a preferred way to
> handle this?

Feel free to add my:

	Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>

I'm also fine with no attribution, but we add that for copyright
reasons, and this is *probably* significant enough to qualify, but I'm
no lawyer etc. Anyway, probably better to add it when in doubt...

>>
>> > -	if (ac < 2 && !new_branch && !opts.detach) {
>> > +	/*
>> > +	 * As the orphan cannot be created until the contents of branch
>> > +	 * are staged, opts.orphan_branch should be treated as both a boolean
>> > +	 * indicating that `--orphan` was selected and as the name of the new
>> > +	 * orphan branch from this point on.
>> > +	 */
>>
>> I've re-read this a couple of times, and I honestly still don't see what
>> point is trying to drive home.
>>
>> So, "--orphan" is an OPT_STRING(), so it always has a value:
>>
>> 	$ ./git worktree add --orphan
>> 	error: option `orphan' requires a value
>>
>> But we init it to NULL, and above we just used it as a boolean *and*
>> below.
>>
>> I.e. this comment would seem to me to fit with code where the reader
>> might be surprised that we're using "opts.orphan_branch" as a string
>> from then on, but we're just copying that to "new_branch", then we
>> always use "opts.orphan_branch" as a boolean for the rest of the
>> function.
>>
>> I may be missing something, but I think this would probably be better
>> just without this comment. E.g. we use "--track", "--lock-reason"
>> etc. in similar ways, and those don't have a comment like that.
>>
>
> Originally the new orphan branch's name was passed into
> `add_worktree(path, refname, opts)` via the `orphan_branch` field in `opts` and
> the branch which was to be checked out first(to mimic `git checkout --orphan`)
> was passed in via `refname`.
>
> Now that the behavior was changed to use `git switch`, that
> "checkout then make orphan" behavior was unneeded and `refname` also contains
> the name of the orphan branch.
>
> For `make_worktree_orphan(opts, child_env)` however since I used the same
> function signature as `checkout_worktree(opts, child_env)`, `refname` wasn't
> passed in and I used `opts->orphan_branch` to access the branch name from
> that scope.
>
> I can change `make_worktree_orphan(opts, child_env)` to
> `make_worktree_orphan(ref, opts, child_env)` instead and then `orphan_branch`
> would be able to be treated as a boolean like those other flags.

I think nothing needs to be changed here on my account, just pointing
out that I found the comment a bit confusing. Do with that what you will
:)

>>
>> > +	if (opts.orphan_branch) {
>> > +		new_branch = opts.orphan_branch;
>> > +	}
>> > +
>> > +	if (ac < 2 && !new_branch && !opts.detach && !opts.orphan_branch) {
>>
>> In general we shouldn't combine random "if"'s just because a a
>> sufficiently smart compiler could discover a way to reduce work.
>>
>> But in this case these seem to be inherently connected, we always want
>> the not-DWIM behavior with "orphan", no?
>>
>> So shouldn't this just be:
>>
>> 	if (opts.orphan_branch) {
>> 		...
>> 	} else if (ac < 2 && !new_branch && !opts.detach) {
>> 		....
>> 	}
>>
>> ?
>
> Yes. I've updated that for v4.

Nice!