[thirdparty/git.git] / git-filter-branch.sh

#!/bin/sh
#
# Rewrite revision history
# Copyright (c) Petr Baudis, 2006
# Minimal changes to "port" it to core-git (c) Johannes Schindelin, 2007
#
# Lets you rewrite the revision history of the current branch, creating
# a new branch. You can specify a number of filters to modify the commits,
# files and trees.

# The following functions will also be available in the commit filter:

functions=$(cat << \EOF
warn () {
	echo "$*" >&2
}

map()
{
	# if it was not rewritten, take the original
	if test -r "$workdir/../map/$1"
	then
		cat "$workdir/../map/$1"
	else
		echo "$1"
	fi
}

# if you run 'skip_commit "$@"' in a commit filter, it will print
# the (mapped) parents, effectively skipping the commit.

skip_commit()
{
	shift;
	while [ -n "$1" ];
	do
		shift;
		map "$1";
		shift;
	done;
}

# if you run 'git_commit_non_empty_tree "$@"' in a commit filter,
# it will skip commits that leave the tree untouched, commit the other.
git_commit_non_empty_tree()
{
	if test $# = 3 && test "$1" = $(git rev-parse "$3^{tree}"); then
		map "$3"
	else
		git commit-tree "$@"
	fi
}
# override die(): this version puts in an extra line break, so that
# the progress is still visible

die()
{
	echo >&2
	echo "$*" >&2
	exit 1
}
EOF
)

eval "$functions"

finish_ident() {
	# Ensure non-empty id name.
	echo "case \"\$GIT_$1_NAME\" in \"\") GIT_$1_NAME=\"\${GIT_$1_EMAIL%%@*}\" && export GIT_$1_NAME;; esac"
	# And make sure everything is exported.
	echo "export GIT_$1_NAME"
	echo "export GIT_$1_EMAIL"
	echo "export GIT_$1_DATE"
}

set_ident () {
	parse_ident_from_commit author AUTHOR committer COMMITTER
	finish_ident AUTHOR
	finish_ident COMMITTER
}

USAGE="[--env-filter <command>] [--tree-filter <command>]
	[--index-filter <command>] [--parent-filter <command>]
	[--msg-filter <command>] [--commit-filter <command>]
	[--tag-name-filter <command>] [--subdirectory-filter <directory>]
	[--original <namespace>] [-d <directory>] [-f | --force]
	[<rev-list options>...]"

OPTIONS_SPEC=
. git-sh-setup

if [ "$(is_bare_repository)" = false ]; then
	require_clean_work_tree 'rewrite branches'
fi

tempdir=.git-rewrite
filter_env=
filter_tree=
filter_index=
filter_parent=
filter_msg=cat
filter_commit=
filter_tag_name=
filter_subdir=
orig_namespace=refs/original/
force=
prune_empty=
remap_to_ancestor=
while :
do
	case "$1" in
	--)
		shift
		break
		;;
	--force|-f)
		shift
		force=t
		continue
		;;
	--remap-to-ancestor)
		# deprecated ($remap_to_ancestor is set now automatically)
		shift
		remap_to_ancestor=t
		continue
		;;
	--prune-empty)
		shift
		prune_empty=t
		continue
		;;
	-*)
		;;
	*)
		break;
	esac

	# all switches take one argument
	ARG="$1"
	case "$#" in 1) usage ;; esac
	shift
	OPTARG="$1"
	shift

	case "$ARG" in
	-d)
		tempdir="$OPTARG"
		;;
	--env-filter)
		filter_env="$OPTARG"
		;;
	--tree-filter)
		filter_tree="$OPTARG"
		;;
	--index-filter)
		filter_index="$OPTARG"
		;;
	--parent-filter)
		filter_parent="$OPTARG"
		;;
	--msg-filter)
		filter_msg="$OPTARG"
		;;
	--commit-filter)
		filter_commit="$functions; $OPTARG"
		;;
	--tag-name-filter)
		filter_tag_name="$OPTARG"
		;;
	--subdirectory-filter)
		filter_subdir="$OPTARG"
		remap_to_ancestor=t
		;;
	--original)
		orig_namespace=$(expr "$OPTARG/" : '\(.*[^/]\)/*$')/
		;;
	*)
		usage
		;;
	esac
done

case "$prune_empty,$filter_commit" in
,)
	filter_commit='git commit-tree "$@"';;
t,)
	filter_commit="$functions;"' git_commit_non_empty_tree "$@"';;
,*)
	;;
*)
	die "Cannot set --prune-empty and --commit-filter at the same time"
esac

case "$force" in
t)
	rm -rf "$tempdir"
;;
'')
	test -d "$tempdir" &&
		die "$tempdir already exists, please remove it"
esac
orig_dir=$(pwd)
mkdir -p "$tempdir/t" &&
tempdir="$(cd "$tempdir"; pwd)" &&
cd "$tempdir/t" &&
workdir="$(pwd)" ||
die ""

# Remove tempdir on exit
trap 'cd "$orig_dir"; rm -rf "$tempdir"' 0

ORIG_GIT_DIR="$GIT_DIR"
ORIG_GIT_WORK_TREE="$GIT_WORK_TREE"
ORIG_GIT_INDEX_FILE="$GIT_INDEX_FILE"
GIT_WORK_TREE=.
export GIT_DIR GIT_WORK_TREE

# Make sure refs/original is empty
git for-each-ref > "$tempdir"/backup-refs || exit
while read sha1 type name
do
	case "$force,$name" in
	,$orig_namespace*)
		die "Cannot create a new backup.
A previous backup already exists in $orig_namespace
Force overwriting the backup with -f"
	;;
	t,$orig_namespace*)
		git update-ref -d "$name" $sha1
	;;
	esac
done < "$tempdir"/backup-refs

# The refs should be updated if their heads were rewritten
git rev-parse --no-flags --revs-only --symbolic-full-name \
	--default HEAD "$@" > "$tempdir"/raw-heads || exit
sed -e '/^^/d' "$tempdir"/raw-heads >"$tempdir"/heads

test -s "$tempdir"/heads ||
	die "Which ref do you want to rewrite?"

GIT_INDEX_FILE="$(pwd)/../index"
export GIT_INDEX_FILE

# map old->new commit ids for rewriting parents
mkdir ../map || die "Could not create map/ directory"

# we need "--" only if there are no path arguments in $@
nonrevs=$(git rev-parse --no-revs "$@") || exit
if test -z "$nonrevs"
then
	dashdash=--
else
	dashdash=
	remap_to_ancestor=t
fi

git rev-parse --revs-only "$@" >../parse

case "$filter_subdir" in
"")
	eval set -- "$(git rev-parse --sq --no-revs "$@")"
	;;
*)
	eval set -- "$(git rev-parse --sq --no-revs "$@" $dashdash \
		"$filter_subdir")"
	;;
esac

git rev-list --reverse --topo-order --default HEAD \
	--parents --simplify-merges --stdin "$@" <../parse >../revs ||
	die "Could not get the commits"
commits=$(wc -l <../revs | tr -d " ")

test $commits -eq 0 && die "Found nothing to rewrite"

# Rewrite the commits
report_progress ()
{
	if test -n "$progress" &&
		test $git_filter_branch__commit_count -gt $next_sample_at
	then
		count=$git_filter_branch__commit_count

		now=$(date +%s)
		elapsed=$(($now - $start_timestamp))
		remaining=$(( ($commits - $count) * $elapsed / $count ))
		if test $elapsed -gt 0
		then
			next_sample_at=$(( ($elapsed + 1) * $count / $elapsed ))
		else
			next_sample_at=$(($next_sample_at + 1))
		fi
		progress=" ($elapsed seconds passed, remaining $remaining predicted)"
	fi
	printf "\rRewrite $commit ($count/$commits)$progress    "
}

git_filter_branch__commit_count=0

progress= start_timestamp=
if date '+%s' 2>/dev/null | grep -q '^[0-9][0-9]*$'
then
	next_sample_at=0
	progress="dummy to ensure this is not empty"
	start_timestamp=$(date '+%s')
fi

while read commit parents; do
	git_filter_branch__commit_count=$(($git_filter_branch__commit_count+1))

	report_progress

	case "$filter_subdir" in
	"")
		GIT_ALLOW_NULL_SHA1=1 git read-tree -i -m $commit
		;;
	*)
		# The commit may not have the subdirectory at all
		err=$(GIT_ALLOW_NULL_SHA1=1 \
		      git read-tree -i -m $commit:"$filter_subdir" 2>&1) || {
			if ! git rev-parse -q --verify $commit:"$filter_subdir"
			then
				rm -f "$GIT_INDEX_FILE"
			else
				echo >&2 "$err"
				false
			fi
		}
	esac || die "Could not initialize the index"

	GIT_COMMIT=$commit
	export GIT_COMMIT
	git cat-file commit "$commit" >../commit ||
		die "Cannot read commit $commit"

	eval "$(set_ident <../commit)" ||
		die "setting author/committer failed for commit $commit"
	eval "$filter_env" < /dev/null ||
		die "env filter failed: $filter_env"

	if [ "$filter_tree" ]; then
		git checkout-index -f -u -a ||
			die "Could not checkout the index"
		# files that $commit removed are now still in the working tree;
		# remove them, else they would be added again
		git clean -d -q -f -x
		eval "$filter_tree" < /dev/null ||
			die "tree filter failed: $filter_tree"

		(
			git diff-index -r --name-only --ignore-submodules $commit &&
			git ls-files --others
		) > "$tempdir"/tree-state || exit
		git update-index --add --replace --remove --stdin \
			< "$tempdir"/tree-state || exit
	fi

	eval "$filter_index" < /dev/null ||
		die "index filter failed: $filter_index"

	parentstr=
	for parent in $parents; do
		for reparent in $(map "$parent"); do
			case "$parentstr " in
			*" -p $reparent "*)
				;;
			*)
				parentstr="$parentstr -p $reparent"
				;;
			esac
		done
	done
	if [ "$filter_parent" ]; then
		parentstr="$(echo "$parentstr" | eval "$filter_parent")" ||
				die "parent filter failed: $filter_parent"
	fi

	{
		while IFS='' read -r header_line && test -n "$header_line"
		do
			# skip header lines...
			:;
		done
		# and output the actual commit message
		cat
	} <../commit |
		eval "$filter_msg" > ../message ||
			die "msg filter failed: $filter_msg"
	workdir=$workdir @SHELL_PATH@ -c "$filter_commit" "git commit-tree" \
		$(git write-tree) $parentstr < ../message > ../map/$commit ||
			die "could not write rewritten commit"
done <../revs

# If we are filtering for paths, as in the 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.
# Ancestor remapping fixes this by mapping these heads to the unique
# nearest ancestor that survived the pruning.

if test "$remap_to_ancestor" = t
then
	while read ref
	do
		sha1=$(git rev-parse "$ref"^0)
		test -f "$workdir"/../map/$sha1 && continue
		ancestor=$(git rev-list --simplify-merges -1 "$ref" "$@")
		test "$ancestor" && echo $(map $ancestor) >> "$workdir"/../map/$sha1
	done < "$tempdir"/heads
fi

# 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"
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"
	;;
	$_x40)
		echo "Ref '$ref' was rewritten"
		if ! git update-ref -m "filter-branch: rewrite" \
					"$ref" $rewritten $sha1 2>/dev/null; then
			if test $(git cat-file -t "$ref") = tag; then
				if test -z "$filter_tag_name"; then
					warn "WARNING: You said to rewrite tagged commits, but not the corresponding tag."
					warn "WARNING: Perhaps use '--tag-name-filter cat' to rewrite the tag."
				fi
			else
				die "Could not rewrite $ref"
			fi
		fi
	;;
	*)
		# NEEDSWORK: possibly add -Werror, making this an error
		warn "WARNING: '$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" $sha1 ||
		 exit
done < "$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 [ "$filter_tag_name" ]; then
	git for-each-ref --format='%(objectname) %(objecttype) %(refname)' refs/tags |
	while read sha1 type ref; do
		ref="${ref#refs/tags/}"
		# XXX: Rewrite tagged trees as well?
		if [ "$type" != "commit" -a "$type" != "tag" ]; then
			continue;
		fi

		if [ "$type" = "tag" ]; then
			# Dereference to a commit
			sha1t="$sha1"
			sha1="$(git rev-parse -q "$sha1"^{commit})" || continue
		fi

		[ -f "../map/$sha1" ] || continue
		new_sha1="$(cat "../map/$sha1")"
		GIT_COMMIT="$sha1"
		export GIT_COMMIT
		new_ref="$(echo "$ref" | eval "$filter_tag_name")" ||
			die "tag name filter failed: $filter_tag_name"

		echo "$ref -> $new_ref ($sha1 -> $new_sha1)"

		if [ "$type" = "tag" ]; then
			new_sha1=$( ( printf 'object %s\ntype commit\ntag %s\n' \
						"$new_sha1" "$new_ref"
				git cat-file tag "$ref" |
				sed -n \
				    -e '1,/^$/{
					  /^object /d
					  /^type /d
					  /^tag /d
					}' \
				    -e '/^-----BEGIN PGP SIGNATURE-----/q' \
				    -e 'p' ) |
				git mktag) ||
				die "Could not create new tag object for $ref"
			if git cat-file tag "$ref" | \
			   sane_grep '^-----BEGIN PGP SIGNATURE-----' >/dev/null 2>&1
			then
				warn "gpg signature stripped from tag object $sha1t"
			fi
		fi

		git update-ref "refs/tags/$new_ref" "$new_sha1" ||
			die "Could not write tag $new_ref"
	done
fi

cd "$orig_dir"
rm -rf "$tempdir"

trap - 0

unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE
test -z "$ORIG_GIT_DIR" || {
	GIT_DIR="$ORIG_GIT_DIR" && export GIT_DIR
}
test -z "$ORIG_GIT_WORK_TREE" || {
	GIT_WORK_TREE="$ORIG_GIT_WORK_TREE" &&
	export GIT_WORK_TREE
}
test -z "$ORIG_GIT_INDEX_FILE" || {
	GIT_INDEX_FILE="$ORIG_GIT_INDEX_FILE" &&
	export GIT_INDEX_FILE
}

if [ "$(is_bare_repository)" = false ]; then
	git read-tree -u -m HEAD || exit
fi

exit 0
Commit	Line	Data
	1	#!/bin/sh
	2	#
	3	# Rewrite revision history
	4	# Copyright (c) Petr Baudis, 2006
	5	# Minimal changes to "port" it to core-git (c) Johannes Schindelin, 2007
	6	#
	7	# Lets you rewrite the revision history of the current branch, creating
	8	# a new branch. You can specify a number of filters to modify the commits,
	9	# files and trees.
	10
	11	# The following functions will also be available in the commit filter:
	12
	13	functions=$(cat << \EOF
	14	warn () {
	15	echo "$*" >&2
	16	}
	17
	18	map()
	19	{
	20	# if it was not rewritten, take the original
	21	if test -r "$workdir/../map/$1"
	22	then
	23	cat "$workdir/../map/$1"
	24	else
	25	echo "$1"
	26	fi
	27	}
	28
	29	# if you run 'skip_commit "$@"' in a commit filter, it will print
	30	# the (mapped) parents, effectively skipping the commit.
	31
	32	skip_commit()
	33	{
	34	shift;
	35	while [ -n "$1" ];
	36	do
	37	shift;
	38	map "$1";
	39	shift;
	40	done;
	41	}
	42
	43	# if you run 'git_commit_non_empty_tree "$@"' in a commit filter,
	44	# it will skip commits that leave the tree untouched, commit the other.
	45	git_commit_non_empty_tree()
	46	{
	47	if test $# = 3 && test "$1" = $(git rev-parse "$3^{tree}"); then
	48	map "$3"
	49	else
	50	git commit-tree "$@"
	51	fi
	52	}
	53	# override die(): this version puts in an extra line break, so that
	54	# the progress is still visible
	55
	56	die()
	57	{
	58	echo >&2
	59	echo "$*" >&2
	60	exit 1
	61	}
	62	EOF
	63	)
	64
	65	eval "$functions"
	66
	67	finish_ident() {
	68	# Ensure non-empty id name.
	69	echo "case \"\$GIT_$1_NAME\" in \"\") GIT_$1_NAME=\"\${GIT_$1_EMAIL%%@*}\" && export GIT_$1_NAME;; esac"
	70	# And make sure everything is exported.
	71	echo "export GIT_$1_NAME"
	72	echo "export GIT_$1_EMAIL"
	73	echo "export GIT_$1_DATE"
	74	}
	75
	76	set_ident () {
	77	parse_ident_from_commit author AUTHOR committer COMMITTER
	78	finish_ident AUTHOR
	79	finish_ident COMMITTER
	80	}
	81
	82	USAGE="[--env-filter <command>] [--tree-filter <command>]
	83	[--index-filter <command>] [--parent-filter <command>]
	84	[--msg-filter <command>] [--commit-filter <command>]
	85	[--tag-name-filter <command>] [--subdirectory-filter <directory>]
	86	[--original <namespace>] [-d <directory>] [-f \| --force]
	87	[<rev-list options>...]"
	88
	89	OPTIONS_SPEC=
	90	. git-sh-setup
	91
	92	if [ "$(is_bare_repository)" = false ]; then
	93	require_clean_work_tree 'rewrite branches'
	94	fi
	95
	96	tempdir=.git-rewrite
	97	filter_env=
	98	filter_tree=
	99	filter_index=
	100	filter_parent=
	101	filter_msg=cat
	102	filter_commit=
	103	filter_tag_name=
	104	filter_subdir=
	105	orig_namespace=refs/original/
	106	force=
	107	prune_empty=
	108	remap_to_ancestor=
	109	while :
	110	do
	111	case "$1" in
	112	--)
	113	shift
	114	break
	115	;;
	116	--force\|-f)
	117	shift
	118	force=t
	119	continue
	120	;;
	121	--remap-to-ancestor)
	122	# deprecated ($remap_to_ancestor is set now automatically)
	123	shift
	124	remap_to_ancestor=t
	125	continue
	126	;;
	127	--prune-empty)
	128	shift
	129	prune_empty=t
	130	continue
	131	;;
	132	-*)
	133	;;
	134	*)
	135	break;
	136	esac
	137
	138	# all switches take one argument
	139	ARG="$1"
	140	case "$#" in 1) usage ;; esac
	141	shift
	142	OPTARG="$1"
	143	shift
	144
	145	case "$ARG" in
	146	-d)
	147	tempdir="$OPTARG"
	148	;;
	149	--env-filter)
	150	filter_env="$OPTARG"
	151	;;
	152	--tree-filter)
	153	filter_tree="$OPTARG"
	154	;;
	155	--index-filter)
	156	filter_index="$OPTARG"
	157	;;
	158	--parent-filter)
	159	filter_parent="$OPTARG"
	160	;;
	161	--msg-filter)
	162	filter_msg="$OPTARG"
	163	;;
	164	--commit-filter)
	165	filter_commit="$functions; $OPTARG"
	166	;;
	167	--tag-name-filter)
	168	filter_tag_name="$OPTARG"
	169	;;
	170	--subdirectory-filter)
	171	filter_subdir="$OPTARG"
	172	remap_to_ancestor=t
	173	;;
	174	--original)
	175	orig_namespace=$(expr "$OPTARG/" : '\(.[^/]\)/$')/
	176	;;
	177	*)
	178	usage
	179	;;
	180	esac
	181	done
	182
	183	case "$prune_empty,$filter_commit" in
	184	,)
	185	filter_commit='git commit-tree "$@"';;
	186	t,)
	187	filter_commit="$functions;"' git_commit_non_empty_tree "$@"';;
	188	,*)
	189	;;
	190	*)
	191	die "Cannot set --prune-empty and --commit-filter at the same time"
	192	esac
	193
	194	case "$force" in
	195	t)
	196	rm -rf "$tempdir"
	197	;;
	198	'')
	199	test -d "$tempdir" &&
	200	die "$tempdir already exists, please remove it"
	201	esac
	202	orig_dir=$(pwd)
	203	mkdir -p "$tempdir/t" &&
	204	tempdir="$(cd "$tempdir"; pwd)" &&
	205	cd "$tempdir/t" &&
	206	workdir="$(pwd)" \|\|
	207	die ""
	208
	209	# Remove tempdir on exit
	210	trap 'cd "$orig_dir"; rm -rf "$tempdir"' 0
	211
	212	ORIG_GIT_DIR="$GIT_DIR"
	213	ORIG_GIT_WORK_TREE="$GIT_WORK_TREE"
	214	ORIG_GIT_INDEX_FILE="$GIT_INDEX_FILE"
	215	GIT_WORK_TREE=.
	216	export GIT_DIR GIT_WORK_TREE
	217
	218	# Make sure refs/original is empty
	219	git for-each-ref > "$tempdir"/backup-refs \|\| exit
	220	while read sha1 type name
	221	do
	222	case "$force,$name" in
	223	,$orig_namespace*)
	224	die "Cannot create a new backup.
	225	A previous backup already exists in $orig_namespace
	226	Force overwriting the backup with -f"
	227	;;
	228	t,$orig_namespace*)
	229	git update-ref -d "$name" $sha1
	230	;;
	231	esac
	232	done < "$tempdir"/backup-refs
	233
	234	# The refs should be updated if their heads were rewritten
	235	git rev-parse --no-flags --revs-only --symbolic-full-name \
	236	--default HEAD "$@" > "$tempdir"/raw-heads \|\| exit
	237	sed -e '/^^/d' "$tempdir"/raw-heads >"$tempdir"/heads
	238
	239	test -s "$tempdir"/heads \|\|
	240	die "Which ref do you want to rewrite?"
	241
	242	GIT_INDEX_FILE="$(pwd)/../index"
	243	export GIT_INDEX_FILE
	244
	245	# map old->new commit ids for rewriting parents
	246	mkdir ../map \|\| die "Could not create map/ directory"
	247
	248	# we need "--" only if there are no path arguments in $@
	249	nonrevs=$(git rev-parse --no-revs "$@") \|\| exit
	250	if test -z "$nonrevs"
	251	then
	252	dashdash=--
	253	else
	254	dashdash=
	255	remap_to_ancestor=t
	256	fi
	257
	258	git rev-parse --revs-only "$@" >../parse
	259
	260	case "$filter_subdir" in
	261	"")
	262	eval set -- "$(git rev-parse --sq --no-revs "$@")"
	263	;;
	264	*)
	265	eval set -- "$(git rev-parse --sq --no-revs "$@" $dashdash \
	266	"$filter_subdir")"
	267	;;
	268	esac
	269
	270	git rev-list --reverse --topo-order --default HEAD \
	271	--parents --simplify-merges --stdin "$@" <../parse >../revs \|\|
	272	die "Could not get the commits"
	273	commits=$(wc -l <../revs \| tr -d " ")
	274
	275	test $commits -eq 0 && die "Found nothing to rewrite"
	276
	277	# Rewrite the commits
	278	report_progress ()
	279	{
	280	if test -n "$progress" &&
	281	test $git_filter_branch__commit_count -gt $next_sample_at
	282	then
	283	count=$git_filter_branch__commit_count
	284
	285	now=$(date +%s)
	286	elapsed=$(($now - $start_timestamp))
	287	remaining=$(( ($commits - $count) * $elapsed / $count ))
	288	if test $elapsed -gt 0
	289	then
	290	next_sample_at=$(( ($elapsed + 1) * $count / $elapsed ))
	291	else
	292	next_sample_at=$(($next_sample_at + 1))
	293	fi
	294	progress=" ($elapsed seconds passed, remaining $remaining predicted)"
	295	fi
	296	printf "\rRewrite $commit ($count/$commits)$progress "
	297	}
	298
	299	git_filter_branch__commit_count=0
	300
	301	progress= start_timestamp=
	302	if date '+%s' 2>/dev/null \| grep -q '^[0-9][0-9]*$'
	303	then
	304	next_sample_at=0
	305	progress="dummy to ensure this is not empty"
	306	start_timestamp=$(date '+%s')
	307	fi
	308
	309	while read commit parents; do
	310	git_filter_branch__commit_count=$(($git_filter_branch__commit_count+1))
	311
	312	report_progress
	313
	314	case "$filter_subdir" in
	315	"")
	316	GIT_ALLOW_NULL_SHA1=1 git read-tree -i -m $commit
	317	;;
	318	*)
	319	# The commit may not have the subdirectory at all
	320	err=$(GIT_ALLOW_NULL_SHA1=1 \
	321	git read-tree -i -m $commit:"$filter_subdir" 2>&1) \|\| {
	322	if ! git rev-parse -q --verify $commit:"$filter_subdir"
	323	then
	324	rm -f "$GIT_INDEX_FILE"
	325	else
	326	echo >&2 "$err"
	327	false
	328	fi
	329	}
	330	esac \|\| die "Could not initialize the index"
	331
	332	GIT_COMMIT=$commit
	333	export GIT_COMMIT
	334	git cat-file commit "$commit" >../commit \|\|
	335	die "Cannot read commit $commit"
	336
	337	eval "$(set_ident <../commit)" \|\|
	338	die "setting author/committer failed for commit $commit"
	339	eval "$filter_env" < /dev/null \|\|
	340	die "env filter failed: $filter_env"
	341
	342	if [ "$filter_tree" ]; then
	343	git checkout-index -f -u -a \|\|
	344	die "Could not checkout the index"
	345	# files that $commit removed are now still in the working tree;
	346	# remove them, else they would be added again
	347	git clean -d -q -f -x
	348	eval "$filter_tree" < /dev/null \|\|
	349	die "tree filter failed: $filter_tree"
	350
	351	(
	352	git diff-index -r --name-only --ignore-submodules $commit &&
	353	git ls-files --others
	354	) > "$tempdir"/tree-state \|\| exit
	355	git update-index --add --replace --remove --stdin \
	356	< "$tempdir"/tree-state \|\| exit
	357	fi
	358
	359	eval "$filter_index" < /dev/null \|\|
	360	die "index filter failed: $filter_index"
	361
	362	parentstr=
	363	for parent in $parents; do
	364	for reparent in $(map "$parent"); do
	365	case "$parentstr " in
	366	" -p $reparent ")
	367	;;
	368	*)
	369	parentstr="$parentstr -p $reparent"
	370	;;
	371	esac
	372	done
	373	done
	374	if [ "$filter_parent" ]; then
	375	parentstr="$(echo "$parentstr" \| eval "$filter_parent")" \|\|
	376	die "parent filter failed: $filter_parent"
	377	fi
	378
	379	{
	380	while IFS='' read -r header_line && test -n "$header_line"
	381	do
	382	# skip header lines...
	383	:;
	384	done
	385	# and output the actual commit message
	386	cat
	387	} <../commit \|
	388	eval "$filter_msg" > ../message \|\|
	389	die "msg filter failed: $filter_msg"
	390	workdir=$workdir @SHELL_PATH@ -c "$filter_commit" "git commit-tree" \
	391	$(git write-tree) $parentstr < ../message > ../map/$commit \|\|
	392	die "could not write rewritten commit"
	393	done <../revs
	394
	395	# If we are filtering for paths, as in the case of a subdirectory
	396	# filter, it is possible that a specified head is not in the set of
	397	# rewritten commits, because it was pruned by the revision walker.
	398	# Ancestor remapping fixes this by mapping these heads to the unique
	399	# nearest ancestor that survived the pruning.
	400
	401	if test "$remap_to_ancestor" = t
	402	then
	403	while read ref
	404	do
	405	sha1=$(git rev-parse "$ref"^0)
	406	test -f "$workdir"/../map/$sha1 && continue
	407	ancestor=$(git rev-list --simplify-merges -1 "$ref" "$@")
	408	test "$ancestor" && echo $(map $ancestor) >> "$workdir"/../map/$sha1
	409	done < "$tempdir"/heads
	410	fi
	411
	412	# Finally update the refs
	413
	414	_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
	415	_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"
	416	echo
	417	while read ref
	418	do
	419	# avoid rewriting a ref twice
	420	test -f "$orig_namespace$ref" && continue
	421
	422	sha1=$(git rev-parse "$ref"^0)
	423	rewritten=$(map $sha1)
	424
	425	test $sha1 = "$rewritten" &&
	426	warn "WARNING: Ref '$ref' is unchanged" &&
	427	continue
	428
	429	case "$rewritten" in
	430	'')
	431	echo "Ref '$ref' was deleted"
	432	git update-ref -m "filter-branch: delete" -d "$ref" $sha1 \|\|
	433	die "Could not delete $ref"
	434	;;
	435	$_x40)
	436	echo "Ref '$ref' was rewritten"
	437	if ! git update-ref -m "filter-branch: rewrite" \
	438	"$ref" $rewritten $sha1 2>/dev/null; then
	439	if test $(git cat-file -t "$ref") = tag; then
	440	if test -z "$filter_tag_name"; then
	441	warn "WARNING: You said to rewrite tagged commits, but not the corresponding tag."
	442	warn "WARNING: Perhaps use '--tag-name-filter cat' to rewrite the tag."
	443	fi
	444	else
	445	die "Could not rewrite $ref"
	446	fi
	447	fi
	448	;;
	449	*)
	450	# NEEDSWORK: possibly add -Werror, making this an error
	451	warn "WARNING: '$ref' was rewritten into multiple commits:"
	452	warn "$rewritten"
	453	warn "WARNING: Ref '$ref' points to the first one now."
	454	rewritten=$(echo "$rewritten" \| head -n 1)
	455	git update-ref -m "filter-branch: rewrite to first" \
	456	"$ref" $rewritten $sha1 \|\|
	457	die "Could not rewrite $ref"
	458	;;
	459	esac
	460	git update-ref -m "filter-branch: backup" "$orig_namespace$ref" $sha1 \|\|
	461	exit
	462	done < "$tempdir"/heads
	463
	464	# TODO: This should possibly go, with the semantics that all positive given
	465	# refs are updated, and their original heads stored in refs/original/
	466	# Filter tags
	467
	468	if [ "$filter_tag_name" ]; then
	469	git for-each-ref --format='%(objectname) %(objecttype) %(refname)' refs/tags \|
	470	while read sha1 type ref; do
	471	ref="${ref#refs/tags/}"
	472	# XXX: Rewrite tagged trees as well?
	473	if [ "$type" != "commit" -a "$type" != "tag" ]; then
	474	continue;
	475	fi
	476
	477	if [ "$type" = "tag" ]; then
	478	# Dereference to a commit
	479	sha1t="$sha1"
	480	sha1="$(git rev-parse -q "$sha1"^{commit})" \|\| continue
	481	fi
	482
	483	[ -f "../map/$sha1" ] \|\| continue
	484	new_sha1="$(cat "../map/$sha1")"
	485	GIT_COMMIT="$sha1"
	486	export GIT_COMMIT
	487	new_ref="$(echo "$ref" \| eval "$filter_tag_name")" \|\|
	488	die "tag name filter failed: $filter_tag_name"
	489
	490	echo "$ref -> $new_ref ($sha1 -> $new_sha1)"
	491
	492	if [ "$type" = "tag" ]; then
	493	new_sha1=$( ( printf 'object %s\ntype commit\ntag %s\n' \
	494	"$new_sha1" "$new_ref"
	495	git cat-file tag "$ref" \|
	496	sed -n \
	497	-e '1,/^$/{
	498	/^object /d
	499	/^type /d
	500	/^tag /d
	501	}' \
	502	-e '/^-----BEGIN PGP SIGNATURE-----/q' \
	503	-e 'p' ) \|
	504	git mktag) \|\|
	505	die "Could not create new tag object for $ref"
	506	if git cat-file tag "$ref" \| \
	507	sane_grep '^-----BEGIN PGP SIGNATURE-----' >/dev/null 2>&1
	508	then
	509	warn "gpg signature stripped from tag object $sha1t"
	510	fi
	511	fi
	512
	513	git update-ref "refs/tags/$new_ref" "$new_sha1" \|\|
	514	die "Could not write tag $new_ref"
	515	done
	516	fi
	517
	518	cd "$orig_dir"
	519	rm -rf "$tempdir"
	520
	521	trap - 0
	522
	523	unset GIT_DIR GIT_WORK_TREE GIT_INDEX_FILE
	524	test -z "$ORIG_GIT_DIR" \|\| {
	525	GIT_DIR="$ORIG_GIT_DIR" && export GIT_DIR
	526	}
	527	test -z "$ORIG_GIT_WORK_TREE" \|\| {
	528	GIT_WORK_TREE="$ORIG_GIT_WORK_TREE" &&
	529	export GIT_WORK_TREE
	530	}
	531	test -z "$ORIG_GIT_INDEX_FILE" \|\| {
	532	GIT_INDEX_FILE="$ORIG_GIT_INDEX_FILE" &&
	533	export GIT_INDEX_FILE
	534	}
	535
	536	if [ "$(is_bare_repository)" = false ]; then
	537	git read-tree -u -m HEAD \|\| exit
	538	fi
	539
	540	exit 0