[PATCH/RFC] filter-branch: Fix to allow replacing submodules with another content

[Michal Sojka <sojkam1@fel.cvut.cz>]

When git filter-branch is used to replace a submodule with another
content, it always fails on the first commit. Consider a repository with
directory submodule containing a submodule. If I want to remove the
submodule and replace it with a file, the following command fails.

git filter-branch --tree-filter 'rm -rf submodule &&
				 git rm -q submodule &&
				 mkdir submodule &&
				 touch submodule/file'

The error message is:
error: submodule: is a directory - add files inside instead

The reason is that git diff-index, which generates a part of the list of
files to update-index, emits also the removed submodule even if it was
replaced by a real directory.

Adding --ignored-submodules solves the problem for me and
tests in t7003-filter-branch.sh passes correctly.

Signed-off-by: Michal Sojka <sojkam1@fel.cvut.cz>
---
 git-filter-branch.sh |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 195b5ef..d4ac7fb 100755
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -331,7 +331,7 @@ while read commit parents; do
 			die "tree filter failed: $filter_tree"
 
 		(
-			git diff-index -r --name-only $commit &&
+			git diff-index -r --name-only --ignore-submodules $commit && 
 			git ls-files --others
 		) > "$tempdir"/tree-state || exit
 		git update-index --add --replace --remove --stdin \
-- 
1.6.6