On 22/11/17 11:00AM, Ævar Arnfjörð Bjarmason wrote:
>
> On Tue, Nov 15 2022, Eric Sunshine wrote:
>
> > On Thu, Nov 10, 2022 at 6:32 PM Jacob Abel <jacobabel@xxxxxxxxxx> wrote:
> >> While working with the worktree based git workflow, I realised that setting
> >> up a new git repository required switching between the traditional and
> >> worktree based workflows. Searching online I found a SO answer [1] which
> >> seemed to support this and which indicated that adding support for this should
> >> not be technically difficult.
> >>
> >> * adding orphan branch functionality (as is present in `git-switch`)
> >> to `git-worktree-add`
> >
> > I haven't had a chance yet to read v3, but can we take a step back for
> > a moment and look at this topic from a slightly different angle?
> > Setting aside the value of adding --orphan to `git worktree add`
> > (which, I'm perfectly fine with, as mentioned earlier), I have a
> > question about whether the solution proposed by this series is the
> > best we can do.
> >
> > As I understand it, the actual problem this series wants to solve is
> > that it's not possible to create a new worktree from an empty bare
> > repository; for instance:
> >
> > % git init --bare foo.git
> > % git -C foo.git worktree add -b main bar
> > Preparing worktree (new branch 'main')
> > fatal: not a valid object name: 'HEAD'
> > %
> >
> > This series addresses that shortcoming by adding --orphan, so that the
> > following works:
> >
> > % git init --bare foo.git
> > % git -C foo.git worktree add --orphan main bar
> > Preparing worktree (new branch 'main')
> > %
> >
> > However, is this really the best and most user-friendly and most
> > discoverable solution? Is it likely that users are somehow going to
> > instinctively use --orphan when they see the "fatal: not a valid
> > object name: 'HEAD'" error message?
> >
> > Wouldn't a better solution be to somehow fix `git worktree add -b
> > <branch>` so that it just works rather than erroring out? I haven't
> > delved into the implementation to determine if this is possible, but
> > if it is, it seems a far superior "fix" for the problem shown above
> > since it requires no extra effort on the user's part, and doesn't
> > raise any discoverability red-flags (since nothing needs to be
> > "discovered" if `-b <branch>` works as expected in the first place).
> >
> > If fixing `-b <branch>` to "just work" is possible, then --orphan is
> > no longer a needed workaround but becomes "icing on the cake".
>
> That's a really good point, and we *could* "fix" that.
>
> But I don't see how to do it without overloading "-b" even further, in a
> way that some users either might not mean, or at least would be
> confusing.
>
> E.g. one script "manually clones" a repo because it does "git init",
> "git remote set-url", "git fetch" etc. Another one makes worktrees from
> those fresh checkouts once set up.
>
> If we "DWYM" here that second step will carry forward the bad state
> instead of erroring early.
>
> I haven't fully thought this throuh, so maybe it's fine, just
> wondering...
>
> ...an alternate way to perhaps to do this would be to detect this
> situation in add(), and emit an advise() telling the user that maybe
> they want to use "--orphan" for this?
>
Prior to writing this patch, I tried to determine if there was a succinct way
to make `-b` "just work" however I wasn't able to find one that wouldn't
introduce unintuitive behavior. My conclusion was that it was probably best
to break it out into a separate command as the other tools had.
I'd support adding an `advise()` for at least the basic case where you try to
create a worktree and no branches currently exist in the repository.
i.e. something like this:
% git init --bare foo.git
% git -C foo.git branch --list
% git -C foo.git worktree add foobar/
hint: If you meant to create a new initial branch for this repository,
hint: e.g. 'main', you can do so using the --orphan option:
hint:
hint: git worktree add --orphan main main/
hint:
fatal: invalid reference: 'foobar'
and
% git init --bare foo.git
% git -C foo.git --no-pager branch --list
% git -C foo.git worktree add -b foobar foobardir/
hint: If you meant to create a new initial branch for this repository,
hint: e.g. 'main', you can do so using the --orphan option:
hint:
hint: git worktree add --orphan main main/
hint:
fatal: invalid reference: 'foobar'
but not in the following circumstances:
% git init --bare foo.git
% ...
% git -C foo.git --no-pager branch --list
+ foo
bar
% git -C foo.git worktree add foobar/
Preparing worktree (new branch 'foobar')
HEAD is now at 319605f8f0 This is a commit message
or
% git init --bare foo.git
% ...
% git -C foo.git --no-pager branch --list
+ foo
bar
% git -C foo.git worktree add -b foobar foobardir/
Preparing worktree (new branch 'foobar)
HEAD is now at 319605f8f0 This is a commit message
Would there be any other circumstances where we'd definitely want an `advise()`?
Generally I'd assume that outside of those two circumstances, most users will
rarely intend to make an orphan without already knowing they absolutely need to
make an orphan.
