Re: [PATCH v2 00/21] Support multiple worktrees

> Duy Nguyen <pclouds@gmail.com> writes:
>
>> I've got a better version [1] that fixes everything I can think of
>> (there's still some room for improvements). I'm going to use it a bit
>> longer before reposting again. But here's its basic design without
>> going down to code
>>
>> New .git file format includes two lines:
>> -- 8< --
>> gitid: <id>
>> gitdir: <path>
>> -- 8< --
>>
>> Which would set $GIT_COMMON_DIR to <path> and $GIT_DIR to
>> <path>/repos/<id>. Repository split is the same as before, worktree
>> stuff in $GIT_DIR, the rest in $GIT_COMMON_DIR. This .git file format
>> takes precedence over core.worktree but can still be overriden with
>> $GIT_WORK_TREE. The main interface to create new worktree is "git
>> checkout --to".
>>
>> "repos" belongs to $GIT_COMMON_DIR (i.e. shared across all checkouts).
>> The new worktrees (which I call "linked checkouts") can also access
>> HEAD of the original worktree via a virtual path "main/HEAD". This
>> makes it possible for a linked checkout to detach HEAD of the main
>> one.
>
> I am not happy with the choice of "main/HEAD" that would squat on a
> good name for remote-tracking branch (i.e. s/origin/main/), though.
> $GIT_DIR/COMMON_HEAD perhaps?

>> The interesting thing is support for third party scripts (or hooks,
>> maybe) so that they could work with both old and new git versions
>> without some sort of git version/feature detection. Of course old git
>> versions will only work with ordinary worktrees. To that end, "git
>> rev-parse --git-dir" behavior could be changed by two environment
>> variables. $GIT_ONE_PATH makes 'rev-parse --git-dir' return the .git
>> _file_ in this case, which makes it much easier to pass the repo's
>> checkout view around with "git --git-dir=... ".$GIT_COMMON_DIR_PATH
>> makes 'rev-parse --git-dir' return $GIT_COMMON_DIR if it's from a
>> linked checkout, or $GIT_DIR otherwise.
>
> I do not understand why you need to go such a route.
>
> Existing scripts that works only in a real repository will only know
> "git rev-parse --git-dir" as the way to get the real GIT_DIR and
> would not care about the "common" thing.  Scripts updated to work
> well with the "common" thing needs to be aware of the "common" thing
> anyway, so adding "git rev-parse --common-git-dir" or somesuch that
> only these updated knows would be sufficient, no?