Re: builtin command's prefix question

> The intention is:
>
>  * If GIT_DIR is set but not GIT_WORK_TREE (nor core.worktree in
>    config), you are either inside project.git/ directory of bare
>    repository or at the toplevel of worktree-full directory.  This has
>    been the traditional behaviour before GIT_WORK_TREE and we shouldn't
>    break the existing setups that assume this behaviour.  So in that
>    sense, with this combination:
>
>    - If the repository is bare, the value of the prefix should not
>      matter; the command that wants to look at prefix by definition
>      wants to run from a subdirectory but there is no notion of
>      "the user directory being a subdirectory of the top of the work
>      tree" in a bare repository;
>
>    - If the repository is not bare, the user directory _MUST_ be at the
>      top of the work tree, as that is what the traditional behaviour is.
>      Anything else would break existing setups.
>
>      IOW, if you use GIT_DIR and still want to run from a subdirectory
>      of the worktree, you must have either GIT_WORK_TREE or
>      core.worktree to tell where the top of the worktree is, and if you
>      don't, then you must be at the top.
>
>    So the right thing to do in this case is not going anywhere and using
>    prefix=NULL.

>  * I would say it is a misconfiguration if GIT_DIR is not set and
>    GIT_WORK_TREE is, as the sole purpose of GIT_WORK_TREE is so that you
>    can work from a subdirectory when you set GIT_DIR.  I may be missing
>    an obvious use case that this is useful, but I do not think of any.
>    Dscho may be able to correct me on this, as he fixed up the original
>    work tree series that was even messier quite a bit during the last
>    round.

> However, if we define setup() to behave this way when GIT_DIR is not
> defined and GIT_WORK_TREE is:
>
>  (1) internally pretend as if GIT_DIR was specified to be the
>      directory where the command was started from (iow, do getcwd()
>      once upon startup);
>
>  (2) chdir to GIT_WORK_TREE (which means "callers of setup() always
>      run from the top of the work tree");
>
>  (3) set prefix to NULL;

> ...
> While I still think the combination is simply crazy and does not make
> any sense, if enough users on the list agrees that it makes sense, I
> wouldn't mind setup() did (1) to (3) mentioned above.  The alternative
> is simply to declare GIT_WOR+1 on whatever way that makes worktree less complicated. so your alternative ++K_TREE without GIT_DIR is a nonsense and
> either error error out or ignore GIT_WORK_TREE, which might be easier to
> explain to people.