Re: [PATCH V2 2/3] wt-status: pass struct repository and wt_status through function parameters

> > Thank you very much for the detailed explanation and for pointing towards
> > the bigger picture.
> >
> > From what I have understood, the worktree being NULL refers to the
> > primary worktree (as it does not indicate which repository so it means in
> > respect to the_repository). So if we want to access the primary worktree
> > of a specific repository or even the local repository, NULL does not carry
> > enough information.
> > And obviously, using NULL as primary worktree introduces extra checks and
> > measures as we saw in the previous discussion.
> >
> > I would be very interested (and the more logical step) to fixing worktree api
> > first, and then revisiting the wt-status series on top of that, once the API
> > makes it possible to rely on wt->repo without the NULL risks.
> >
> > So a possible in the worktree api cleanup approach could be,
> >
> > * Make primary worktree as an instance of struct worktree but seperate
> > it by having a marker like id = NULL.
> >
>
> I would like to point out that we already have a function which provides
> a main worktree, see both `get_main_worktree()` & `is_main_worktree()`.
> In short, a worktree with id = NULL seems to be treated as the main
> worktree.
>
> The harder part would be correcting all code where `struct worktree *`
> is passed and has special meaning for NULL vs non-NULL. See
> `strbuf_worktree_gitdir()` which also distinguishes between `wt ==
> NULL`, `wt->id == NULL` and `wt->id != NULL`.
>
> So cleanup would require identifying all such spots and fixing them too.
>
> > * Add this primary worktree in the struct repository (e.g. repo->primary_wt).
> >
>
> This also is tricky. We currently already store all worktrees in the
> repository in `struct strmap worktree_ref_stores`. Here, for the main
> worktree we use '\' (see `get_worktree_ref_store()`). So perhaps we
> should formalize using `\` for the main worktree everywhere.