Re: Alternates and push

> We could instead redefine the semantics of the existing alternates
> mechanism.  This technically *breaks* backward compatibility, but I
> suspect it won't hurt many existing installations:
> 
>  - Declare that a freestanding object store is illegal.  In other words,
>    if a directory "$D/objects" is (1) used as $GIT_OBJECT_DIRECTORY's
>    value, (2) pointed by some repository's "alternates" file, or (3)
>    listed in $GIT_ALTERNATE_OBJECT_DIRECTORIES's value, this change makes
>    it illegal for "$D" not being a proper git repository.
> 
>    This will not break your example of your repository's object store
>    borrowing from the object store inside Linus's repository.
> 
>  - When you have "$D/objects" in alternates, start relying on "$D/refs"
>    being correct (i.e. repository $D is not corrupt).  This technically
>    makes the system slightly less robust, as we are depending on _other
>    people's_ good behaviour even more when you use alternates, but you are
>    already depending on them having good objects in $D/objects anyway, so
>    it is not a big deal.