Re: [PATCH 1/2] store submodule in common dir

[Junio C Hamano <gitster@pobox.com>]

Junio C Hamano <gitster@pobox.com> writes:

> My understanding of what Joakim wants to do is to have a top-level
> project that has three subdirectories, e.g. kernel/v2.2, kernel/v2.4
> and kernel/v2.6, each of which is a submodule that houses these
> versions of Linux kernel source, but only clone Linus's repository
> (as the up-to-late tree has all the necessary history to check out
> these past development tracks).  And that should be doable with
> just the main checkout, without any additional worktree (it's just
> the matter of having .git/modules/kernel%2fv2.6/ directory pointed
> by two symlinks from .git/modules/kernel%2fv2.[24], or something
> like that).

Actually I take the last part of that back.  When thought naively
about, it may appear that it should be doable, but because each of
the modules/* directory in the top-level project has to serve as the
$GIT_DIR for each submodule checkout, and the desire is to have
these three directories to have checkout of three different
branches, a single directory under modules/. that is shared among
three submodules would *not* work---they must have separate index,
HEAD, etc.

Theoretically we should be able to make modules/kernel%2fv2.[24]
additional "worktree"s of modules/kernel%2fv2.6, but given that
these are all "bare" repositories without an attached working tree,
I am not sure how that would supposed to work.  Thinking about
having multiple worktrees on a single bare repository makes me head
spin and ache X-<;-)