Re: [PATCH] unpack-trees.c: assume submodules are clean during check-out

On 2007-08-05 10:46, Sven Verdoolaege wrote:

quoted

$ git checkout experimental-death-ray
$ git submodules update
(return a week later, woozy from the vacation.)
$ git checkout master

Here, it'll warn that your submodule isn't up-to-date.

quoted

(hack hack hack)
$ git commit -a -m "fixed typos"

And if you run "git status" first, it'll tell you that the submodule
(still) isn't up-to-date.

quoted

$ git push
(Oops. You've just accidentally committed the wrong submodule heads.)

You always have to be careful when doing "git commit -a".

Exactly. You now have to be very careful, whereas previously
$ git checkout master && vi foo && git commit -a -m "fixed typos"
was perfectly safe.

Worse yet, it could also be a script making similar assumptions. For
example, consider the tree filter in git-filter-branch. It used to be
fine, but will now corrupt the rewritten trees when submodules are
involved. Here's the relevant code from git-filter-branch.sh:

-----------------------------------------------------------------
while read commit parents; do
...
		git read-tree -i -m $commit
...
		git checkout-index -f -u -a ||
			die "Could not checkout the index"
...
		eval "$filter_tree" < /dev/null ||
			die "tree filter failed: $filter_tree"

		git diff-index -r $commit | cut -f 2- | tr '\n' '\0' | \
			xargs -0 git update-index --add --replace --remove
...
	sh -c "$filter_commit" "git commit-tree" \
		$(git write-tree) $parentstr < ../message > ../map/$commit
done <../revs
-----------------------------------------------------------------

quoted

Another approach is for pull, checkout etc. to automatically update the
submodule' head ref, but no more.

Then everything, including "git submodule update", would assume
that the submodule is up-to-date.

With that approach, "git submodule update" would fetch the submodule's
head commit (which could be missing), and then check it against the
submodule's index (and maybe its work tree).

  Eran