Re: [PATCH v4 4/4] worktree: make add <path> dwim

From: Junio C Hamano <gitster@pobox.com>
Date: Nov 24, 2017, 07:11 UTC
Message-ID: <xmqq1skonoaw.fsf@gitster.mtv.corp.google.com>
In-Reply-To: <20171122223020.2780-5-t.gummerer@gmail.com>

Thomas Gummerer <t.gummerer@gmail.com> writes:

Show 14 quoted lines

> Currently 'git worktree add <path>' creates a new branch named after the
> basename of the <path>, that matches the HEAD of whichever worktree we
> were on when calling "git worktree add <path>".
>
> Make 'git worktree add <path> behave more like the dwim machinery in
> 'git checkout <new-branch>', i.e. check if the new branch name uniquely
> matches the branch name of a remote tracking branch, and if so check out
> that branch and set the upstream to the remote tracking branch.
>
> This is a change of behaviour compared to the current behaviour, where
> we create a new branch matching HEAD.  However as 'git worktree' is
> still an experimental feature, and it's easy to notice/correct the
> behaviour in case it's not what the user desired it's probably okay to
> break existing behaviour here.

Is it "easy to notice"? I doubt it. Even if you assume that everybody uses bash prompt that shows the name of the branch, the user sees the same name of the branch in either mode.

> In order to also satisfy users who want the current behaviour of
> creating a new branch from HEAD, add a '--no-track' flag, which disables
> the new behaviour, and keeps the old behaviour of creating a new branch
> from the head of the current worktree.

I am not sure if this is a good match for "--track/--no-track"; which branch is to be checked out (either "automatically from the unique remote-tracking branch" or "the current one") is one choice, and whether the resulting branch is marked explicitly as integrating with the remote or not is another choice within one branch of the first choice. IOW, this makes it impossible to say "create the branch based on the unique remote-tracking branch, but do not add the two branch.*.{merge,remote} variables".

Also, you have several mention of "remote tracking branch" in these patches. Please consistently spell them as "remote-tracking branch" to be consistent with Documentation/glossary-content.txt and avoid a casual/careful reference to "tracking branch" if possible, unless it is quite clear to the readers that you are being loose for the sake of brevity. Some people used "tracking branch" to mean the local branch that is marked as the branch to integrate with the work on a branch at a remote that caused user confusion in the past.

That is

    refs/remotes/origin/topic is a remote-tracking branch for the
    branch 'topic' that came from the 'origin' remote.

    when you have branch.foo.remote=origin and
    branch.foo.merge=refs/heads/topic, then your local branch foo is
    marked to integrate with the 'topic' branch at the 'origin'
    remote.

and these two are quite different things that people in the past and over time loosely used a phrase "tracking branch" to cause confusion.