Commit dfd05e38 authored by Johannes Schindelin's avatar Johannes Schindelin Committed by Junio C Hamano

filter-branch: Big syntax change; support rewriting multiple refs

We used to take the first non-option argument as the name for the new
branch.  This syntax is not extensible to support rewriting more than just

Instead, we now have the following syntax:

	git filter-branch [<filter options>...] [<rev-list options>]

All positive refs given in <rev-list options> are rewritten.  Yes,
in-place.  If a ref was changed, the original head is stored in
refs/original/$ref now, for your inspecting pleasure, in addition to the
reflogs (since it is easier to inspect "git show-ref | grep original" than
to inspect all the reflogs).

This commit also adds the --force option to remove .git-rewrite/ and all
refs from refs/original/ before filtering.
Signed-off-by: Johannes Schindelin's avatarJohannes Schindelin <>
Signed-off-by: default avatarJunio C Hamano <>
parent 3b38ec16
......@@ -12,7 +12,7 @@ SYNOPSIS
[--index-filter <command>] [--parent-filter <command>]
[--msg-filter <command>] [--commit-filter <command>]
[--tag-name-filter <command>] [--subdirectory-filter <directory>]
[-d <directory>] <new-branch-name> [<rev-list options>...]
[-d <directory>] [-f | --force] [<rev-list options>...]
......@@ -26,10 +26,9 @@ information) will be preserved.
The command takes the new branch name as a mandatory argument and
the filters as optional arguments. If you specify no filters, the
commits will be recommitted without any changes, which would normally
have no effect and result in the new branch pointing to the same
branch as your current branch. Nevertheless, this may be useful in
the future for compensating for some git bugs or such, therefore
such a usage is permitted.
have no effect. Nevertheless, this may be useful in the future for
compensating for some git bugs or such, therefore such a usage is
*WARNING*! The rewritten history will have different object names for all
the objects and will not converge with the original branch. You will not
......@@ -38,8 +37,9 @@ original branch. Please do not use this command if you do not know the
full implications, and avoid using it anyway, if a simple single commit
would suffice to fix your problem.
Always verify that the rewritten version is correct before disposing
the original branch.
Always verify that the rewritten version is correct: The original refs,
if different from the rewritten ones, will be stored in the namespace
Note that since this operation is extensively I/O expensive, it might
be a good idea to redirect the temporary directory off-disk, e.g. on
......@@ -142,6 +142,11 @@ definition impossible to preserve signatures at any rate.)
does this in the '.git-rewrite/' directory but you can override
that choice by this parameter.
`git filter-branch` refuses to start with an existing temporary
directory or when there are already refs starting with
'refs/original/', unless forced.
When options are given after the new branch name, they will
be passed to gitlink:git-rev-list[1]. Only commits in the resulting
......@@ -156,14 +161,14 @@ Suppose you want to remove a file (containing confidential information
or copyright violation) from all commits:
git filter-branch --tree-filter 'rm filename' newbranch
git filter-branch --tree-filter 'rm filename' HEAD
A significantly faster version:
git filter-branch --index-filter 'git update-index --remove filename' newbranch
git filter-branch --index-filter 'git update-index --remove filename' HEAD
Now, you will get the rewritten history saved in the branch 'newbranch'
(your current branch is left untouched).
......@@ -172,25 +177,25 @@ To set a commit (which typically is at the tip of another
history) to be the parent of the current initial commit, in
order to paste the other history behind the current history:
git filter-branch --parent-filter 'sed "s/^\$/-p <graft-id>/"' newbranch
git filter-branch --parent-filter 'sed "s/^\$/-p <graft-id>/"' HEAD
(if the parent string is empty - therefore we are dealing with the
initial commit - add graftcommit as a parent). Note that this assumes
history with a single root (that is, no merge without common ancestors
happened). If this is not the case, use:
git filter-branch --parent-filter \
'cat; test $GIT_COMMIT = <commit-id> && echo "-p <graft-id>"' newbranch
'cat; test $GIT_COMMIT = <commit-id> && echo "-p <graft-id>"' HEAD
or even simpler:
echo "$commit-id $graft-id" >> .git/info/grafts
git filter-branch newbranch $graft-id..
git filter-branch $graft-id..HEAD
To remove commits authored by "Darl McBribe" from the history:
......@@ -208,7 +213,7 @@ git filter-branch --commit-filter '
git commit-tree "$@";
fi' newbranch
fi' HEAD
The shift magic first throws away the tree id and then the -p
......@@ -238,14 +243,14 @@ A--B-----C
To rewrite only commits D,E,F,G,H, but leave A, B and C alone, use:
git filter-branch ... new-H C..H
git filter-branch ... C..H
To rewrite commits E,F,G,H, use one of these:
git filter-branch ... new-H C..H --not D
git filter-branch ... new-H D..H --not C
git filter-branch ... C..H --not D
git filter-branch ... D..H --not C
To move the whole tree into a subdirectory, or remove it from there:
......@@ -255,7 +260,7 @@ git filter-branch --index-filter \
'git ls-files -s | sed "s-\t-&newsubdir/-" |
git update-index --index-info &&
mv $ $GIT_INDEX_FILE' directorymoved
......@@ -78,6 +78,8 @@ filter_msg=cat
filter_commit='git commit-tree "$@"'
while case "$#" in 0) usage;; esac
case "$1" in
......@@ -85,6 +87,11 @@ do
......@@ -126,24 +133,43 @@ do
test -n "$dstbranch" || die "missing branch name"
git show-ref "refs/heads/$dstbranch" 2> /dev/null &&
die "branch $dstbranch already exists"
test ! -e "$tempdir" || die "$tempdir already exists, please remove it"
case "$force" in
rm -rf "$tempdir"
test -d "$tempdir" &&
die "$tempdir already exists, please remove it"
mkdir -p "$tempdir/t" &&
tempdir="$(cd "$tempdir"; pwd)" &&
cd "$tempdir/t" &&
workdir="$(pwd)" ||
die ""
# Make sure refs/original is empty
git for-each-ref > "$tempdir"/backup-refs
while read sha1 type name
case "$force,$name" in
die "Namespace $orig_namespace not empty"
git update-ref -d "$name" $sha1
done < "$tempdir"/backup-refs
case "$GIT_DIR" in
......@@ -153,6 +179,29 @@ case "$GIT_DIR" in
# These refs should be updated if their heads were rewritten
git rev-parse --revs-only --symbolic "$@" |
while read ref
# normalize ref
case "$ref" in
ref="$(git symbolic-ref "$ref")"
ref="$(git for-each-ref --format='%(refname)' |
grep /"$ref")"
git check-ref-format "$ref" && echo "$ref"
done > "$tempdir"/heads
test -s "$tempdir"/heads ||
die "Which ref do you want to rewrite?"
export GIT_INDEX_FILE="$(pwd)/../index"
git read-tree || die "Could not seed the index"
......@@ -174,6 +223,8 @@ commits=$(wc -l <../revs | tr -d " ")
test $commits -eq 0 && die "Found nothing to rewrite"
# Rewrite the commits
while read commit parents; do
......@@ -234,22 +285,75 @@ while read commit parents; do
$(git write-tree) $parentstr < ../message > ../map/$commit
done <../revs
src_head=$(tail -n 1 ../revs | sed -e 's/ .*//')
target_head=$(head -n 1 ../map/$src_head)
case "$target_head" in
echo Nothing rewritten
# In case of a subdirectory filter, it is possible that a specified head
# is not in the set of rewritten commits, because it was pruned by the
# revision walker. Fix it by mapping these heads to the next rewritten
# ancestor(s), i.e. the boundaries in the set of rewritten commits.
# NEEDSWORK: we should sort the unmapped refs topologically first
while read ref
sha1=$(git rev-parse "$ref"^0)
test -f "$workdir"/../map/$sha1 && continue
# Assign the boundarie(s) in the set of rewritten commits
# as the replacement commit(s).
# (This would look a bit nicer if --not --stdin worked.)
for p in $((cd "$workdir"/../map; ls | sed "s/^/^/") |
git rev-list $ref --boundary --stdin |
sed -n "s/^-//p")
map $p >> "$workdir"/../map/$sha1
done < "$tempdir"/heads
# Finally update the refs
while read ref
# avoid rewriting a ref twice
test -f "$orig_namespace$ref" && continue
sha1=$(git rev-parse "$ref"^0)
rewritten=$(map $sha1)
test $sha1 = "$rewritten" &&
warn "WARNING: Ref '$ref' is unchanged" &&
case "$rewritten" in
echo "Ref '$ref' was deleted"
git update-ref -m "filter-branch: delete" -d "$ref" $sha1 ||
die "Could not delete $ref"
git update-ref refs/heads/"$dstbranch" $target_head ||
die "Could not update $dstbranch with $target_head"
if [ $(wc -l <../map/$src_head) -gt 1 ]; then
echo "WARNING: Your commit filter caused the head commit to expand to several rewritten commits. Only the first such commit was recorded as the current $dstbranch head but you will need to resolve the situation now (probably by manually merging the other commits). These are all the commits:" >&2
sed 's/^/ /' ../map/$src_head >&2
echo "Ref '$ref' was rewritten"
git update-ref -m "filter-branch: rewrite" \
"$ref" $rewritten $sha1 ||
die "Could not rewrite $ref"
# NEEDSWORK: possibly add -Werror, making this an error
warn "WARNING: '$ref' was rewritten into multiple commits:"
warn "$rewritten"
warn "WARNING: Ref '$ref' points to the first one now."
rewritten=$(echo "$rewritten" | head -n 1)
git update-ref -m "filter-branch: rewrite to first" \
"$ref" $rewritten $sha1 ||
die "Could not rewrite $ref"
git update-ref -m "filter-branch: backup" "$orig_namespace$ref" $sha1
done < "$tempdir"/heads
# TODO: This should possibly go, with the semantics that all positive given
# refs are updated, and their original heads stored in refs/original/
# Filter tags
if [ "$filter_tag_name" ]; then
git for-each-ref --format='%(objectname) %(objecttype) %(refname)' refs/tags |
......@@ -286,6 +390,8 @@ fi
cd ../..
rm -rf "$tempdir"
printf "\nRewritten history saved to the $dstbranch branch\n"
test $count -gt 0 && echo "These refs were rewritten:"
git show-ref | grep ^"$orig_namespace"
exit $ret
......@@ -30,24 +30,24 @@ test_expect_success 'setup' '
H=$(git rev-parse H)
test_expect_success 'rewrite identically' '
git-filter-branch H2
git-filter-branch branch
test_expect_success 'result is really identical' '
test $H = $(git rev-parse H2)
test $H = $(git rev-parse HEAD)
test_expect_success 'rewrite, renaming a specific file' '
git-filter-branch --tree-filter "mv d doh || :" H3
git-filter-branch -f --tree-filter "mv d doh || :" HEAD
test_expect_success 'test that the file was renamed' '
test d = $(git show H3:doh)
test d = $(git show HEAD:doh)
git tag oldD H3~4
git tag oldD HEAD~4
test_expect_success 'rewrite one branch, keeping a side branch' '
git-filter-branch --tree-filter "mv b boh || :" modD D..oldD
git branch modD oldD &&
git-filter-branch -f --tree-filter "mv b boh || :" D..modD
test_expect_success 'common ancestor is still common (unchanged)' '
......@@ -69,7 +69,8 @@ test_expect_success 'filter subdirectory only' '
git rm a &&
test_tick &&
git commit -m "again not subdir" &&
git-filter-branch --subdirectory-filter subdir sub
git branch sub &&
git-filter-branch -f --subdirectory-filter subdir refs/heads/sub
test_expect_success 'subdirectory filter result looks okay' '
......@@ -89,7 +90,8 @@ test_expect_success 'setup and filter history that requires --full-history' '
test_tick &&
git commit -m "again subdir on master" &&
git merge branch &&
git-filter-branch --subdirectory-filter subdir sub-master
git branch sub-master &&
git-filter-branch -f --subdirectory-filter subdir sub-master
test_expect_success 'subdirectory filter result looks okay' '
......@@ -100,7 +102,8 @@ test_expect_success 'subdirectory filter result looks okay' '
test_expect_success 'use index-filter to move into a subdirectory' '
git-filter-branch --index-filter \
git branch directorymoved &&
git-filter-branch -f --index-filter \
"git ls-files -s | sed \"s-\\t-&newsubdir/-\" |
git update-index --index-info &&
......@@ -108,9 +111,10 @@ test_expect_success 'use index-filter to move into a subdirectory' '
test -z "$(git diff HEAD directorymoved:newsubdir)"'
test_expect_success 'stops when msg filter fails' '
! git-filter-branch --msg-filter false nonono &&
rm -rf .git-rewrite &&
! git rev-parse nonono
old=$(git rev-parse HEAD) &&
! git-filter-branch -f --msg-filter false &&
test $old = $(git rev-parse HEAD) &&
rm -rf .git-rewrite
test_expect_success 'author information is preserved' '
......@@ -118,7 +122,8 @@ test_expect_success 'author information is preserved' '
git add i &&
test_tick &&
GIT_AUTHOR_NAME="B V Uips" git commit -m bvuips &&
git-filter-branch --msg-filter "cat; \
git branch preserved-author &&
git-filter-branch -f --msg-filter "cat; \
test \$GIT_COMMIT != $(git rev-parse master) || \
echo Hallo" \
preserved-author &&
......@@ -129,7 +134,8 @@ test_expect_success "remove a certain author's commits" '
echo i > i &&
test_tick &&
git commit -m i i &&
git-filter-branch --commit-filter "\
git branch removed-author &&
git-filter-branch -f --commit-filter "\
if [ \"\$GIT_AUTHOR_NAME\" = \"B V Uips\" ];\
......@@ -148,4 +154,9 @@ test_expect_success "remove a certain author's commits" '
test 0 = $(git rev-list --author="B V Uips" removed-author | wc -l)
test_expect_success 'barf on invalid name' '
! git filter-branch -f master xy-problem &&
! git filter-branch -f HEAD^
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment