'git submodule update --merge' merges the commit referenced by the
superproject into your local branch, instead of checking it out on
a detached HEAD.
As evidenced by the addition of "git submodule update --rebase", it
is useful to provide alternatives to the default 'checkout' behaviour
of "git submodule update". One such alternative is, when updating a
submodule to a new commit, to merge that commit into the current
local branch in that submodule. This is useful in workflows where
you want to update your submodule from its upstream, but you cannot
use --rebase, because you have downstream people working on top of
your submodule branch, and you don't want to disrupt their work.
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The addition of "submodule.<name>.rebase" demonstrates the usefulness of
alternatives to the default behaviour of "git submodule update". However,
by naming the config variable "submodule.<name>.rebase", and making it a
boolean choice, we are artificially constraining future git versions that
may want to add _more_ alternatives than just "rebase".
Therefore, while "submodule.<name>.rebase" is not yet in a stable git
release, future-proof it, by changing it from
submodule.<name>.rebase = true/false
to
submodule.<name>.update = rebase/checkout
where "checkout" specifies the default behaviour of "git submodule update"
(checking out the new commit to a detached HEAD), and "rebase" specifies
the --rebase behaviour (where the current local branch in the submodule is
rebase onto the new commit). Thus .update == checkout is equivalent to
.rebase == false, and .update == rebase is equivalent to .rebase == true.
Finally, leaving .update unset is equivalent to leaving .rebase unset.
In future git versions, other alternatives to "git submodule update"
behaviour can be included by adding them to the list of allowable values
for the submodule.<name>.update variable.
Signed-off-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
'git submodule update --rebase' rebases your local branch on top of what
would have been checked out to a detached HEAD otherwise.
In some cases, detaching the HEAD when updating a submodule complicates
the workflow to commit to this submodule (checkout master, rebase, then
commit). For submodules that require frequent updates but infrequent
(if any) commits, a rebase can be executed directly by the git-submodule
command, ensuring that the submodules stay on their respective branches.
git-config key: submodule.$name.rebase (bool)
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
