PATCH] Allow git-filter-branch to process large repositories with lots of branches.

As noted in several forums, a recommended way to move trees between
repositories is to use git-filter-branch to revise the history for a
single tree 
(http://gbayer.com/development/moving-files-from-one-git-repository-to-anot
her-preserving-history/,
http://stackoverflow.com/questions/1365541/how-to-move-files-from-one-git-r
epo-to-another-not-a-clone-preserving-history).

However, this can lead to argument list too long errors when the original
repository has many retained branches (>6k)

/usr/local/git/libexec/git-core/git-filter-branch: line 270:
/usr/local/git/libexec/git-core/git: Argument list too long
Could not get the commits

Piping the output from git rev-parse directly into git rev-list avoids
this problem, since the rev-parse output is not processed as a command
line argument.
---
 git-filter-branch.sh | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index ac2a005..d7e0fae 100755
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh

@@ -255,8 +255,6 @@ else
 	remap_to_ancestor=t
 fi
 
-rev_args=$(git rev-parse --revs-only "$@")
-
 case "$filter_subdir" in
 "")
 	eval set -- "$(git rev-parse --sq --no-revs "$@")"

@@ -267,8 +265,9 @@ case "$filter_subdir" in
 	;;
 esac
 
+git rev-parse --revs-only "$@" | \
 git rev-list --reverse --topo-order --default HEAD \
-	--parents --simplify-merges $rev_args "$@" > ../revs ||
+	--parents --simplify-merges --stdin "$@" > ../revs ||
 	die "Could not get the commits"
 commits=$(wc -l <../revs | tr -d " ")
 

-- 
1.8.3.2