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
HEAD.
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/$ref now, for your inspecting pleasure, in addition to the
reflogs (since it is easier to inspect "git show-ref | grep original" than
to inspect all the reflogs).
This commit also adds the --force option to remove .git-rewrite/ and all
refs from refs/original/ before filtering.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/git-filter-branch.sh b/git-filter-branch.sh
index 0d000ed..0ff3475 100755
--- a/git-filter-branch.sh
+++ b/git-filter-branch.sh
@@ -78,6 +78,8 @@
filter_commit='git commit-tree "$@"'
filter_tag_name=
filter_subdir=
+orig_namespace=refs/original/
+force=
while case "$#" in 0) usage;; esac
do
case "$1" in
@@ -85,6 +87,11 @@
shift
break
;;
+ --force|-f)
+ shift
+ force=t
+ continue
+ ;;
-*)
;;
*)
@@ -126,24 +133,43 @@
--subdirectory-filter)
filter_subdir="$OPTARG"
;;
+ --original)
+ orig_namespace="$OPTARG"
+ ;;
*)
usage
;;
esac
done
-dstbranch="$1"
-shift
-test -n "$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
+t)
+ rm -rf "$tempdir"
+;;
+'')
+ test -d "$tempdir" &&
+ die "$tempdir already exists, please remove it"
+esac
mkdir -p "$tempdir/t" &&
+tempdir="$(cd "$tempdir"; pwd)" &&
cd "$tempdir/t" &&
workdir="$(pwd)" ||
die ""
+# Make sure refs/original is empty
+git for-each-ref > "$tempdir"/backup-refs
+while read sha1 type name
+do
+ case "$force,$name" in
+ ,$orig_namespace*)
+ die "Namespace $orig_namespace not empty"
+ ;;
+ t,$orig_namespace*)
+ git update-ref -d "$name" $sha1
+ ;;
+ esac
+done < "$tempdir"/backup-refs
+
case "$GIT_DIR" in
/*)
;;
@@ -153,6 +179,29 @@
esac
export GIT_DIR GIT_WORK_TREE=.
+# These refs should be updated if their heads were rewritten
+
+git rev-parse --revs-only --symbolic "$@" |
+while read ref
+do
+ # normalize ref
+ case "$ref" in
+ HEAD)
+ ref="$(git symbolic-ref "$ref")"
+ ;;
+ refs/*)
+ ;;
+ *)
+ ref="$(git for-each-ref --format='%(refname)' |
+ grep /"$ref")"
+ esac
+
+ git check-ref-format "$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 @@
test $commits -eq 0 && die "Found nothing to rewrite"
+# Rewrite the commits
+
i=0
while read commit parents; do
i=$(($i+1))
@@ -234,22 +285,75 @@
$(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
+do
+ 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")
+ do
+ map $p >> "$workdir"/../map/$sha1
+ done
+done < "$tempdir"/heads
+
+# Finally update the refs
+
+_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
+_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
+count=0
+echo
+while read ref
+do
+ # 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 '$ref' is unchanged" &&
+ continue
+
+ case "$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
- ret=1
- fi
+ $_x40)
+ echo "Ref '$ref' was rewritten"
+ git update-ref -m "filter-branch: rewrite" \
+ "$ref" $rewritten $sha1 ||
+ die "Could not rewrite $ref"
;;
-esac
+ *)
+ # NEEDSWORK: possibly add -Werror, making this an error
+ warn "WARNING: '$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 $ref"
+ ;;
+ esac
+ git update-ref -m "filter-branch: backup" "$orig_namespace$ref" $sha1
+ count=$(($count+1))
+done < "$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 [ "$filter_tag_name" ]; then
git for-each-ref --format='%(objectname) %(objecttype) %(refname)' refs/tags |
@@ -286,6 +390,8 @@
cd ../..
rm -rf "$tempdir"
-printf "\nRewritten history saved to the $dstbranch branch\n"
+echo
+test $count -gt 0 && echo "These refs were rewritten:"
+git show-ref | grep ^"$orig_namespace"
exit $ret
