git/git-filter-branch.sh
Johannes Schindelin c401b33c34 Document git-filter-branch
This moves the documentation in git-filter-branch.sh to its own
man page, with a few touch ups (incorporating comments by Frank
Lichtenheld).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-07-03 19:04:49 -07:00

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#!/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.
set -e
USAGE="git-filter-branch [-d TEMPDIR] [FILTERS] DESTBRANCH [REV-RANGE]"
. git-sh-setup
map()
{
# if it was not rewritten, take the original
test -r "$workdir/../map/$1" || echo "$1"
cat "$workdir/../map/$1"
}
# When piped a commit, output a script to set the ident of either
# "author" or "committer
set_ident () {
lid="$(echo "$1" | tr "A-Z" "a-z")"
uid="$(echo "$1" | tr "a-z" "A-Z")"
pick_id_script='
/^'$lid' /{
s/'\''/'\''\\'\'\''/g
h
s/^'$lid' \([^<]*\) <[^>]*> .*$/\1/
s/'\''/'\''\'\'\''/g
s/.*/export GIT_'$uid'_NAME='\''&'\''/p
g
s/^'$lid' [^<]* <\([^>]*\)> .*$/\1/
s/'\''/'\''\'\'\''/g
s/.*/export GIT_'$uid'_EMAIL='\''&'\''/p
g
s/^'$lid' [^<]* <[^>]*> \(.*\)$/\1/
s/'\''/'\''\'\'\''/g
s/.*/export GIT_'$uid'_DATE='\''&'\''/p
q
}
'
LANG=C LC_ALL=C sed -ne "$pick_id_script"
# Ensure non-empty id name.
echo "[ -n \"\$GIT_${uid}_NAME\" ] || export GIT_${uid}_NAME=\"\${GIT_${uid}_EMAIL%%@*}\""
}
tempdir=.git-rewrite
filter_env=
filter_tree=
filter_index=
filter_parent=
filter_msg=cat
filter_commit='git commit-tree "$@"'
filter_tag_name=
filter_subdir=
while case "$#" in 0) usage;; esac
do
case "$1" in
--)
shift
break
;;
-*)
;;
*)
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="$OPTARG"
;;
--tag-name-filter)
filter_tag_name="$OPTARG"
;;
--subdirectory-filter)
filter_subdir="$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 "$tempdir already exists, please remove it"
mkdir -p "$tempdir/t"
cd "$tempdir/t"
workdir="$(pwd)"
case "$GIT_DIR" in
/*)
;;
*)
GIT_DIR="$(pwd)/../../$GIT_DIR"
;;
esac
export GIT_DIR GIT_WORK_TREE=.
export GIT_INDEX_FILE="$(pwd)/../index"
git read-tree # seed the index file
ret=0
mkdir ../map # map old->new commit ids for rewriting parents
case "$filter_subdir" in
"")
git rev-list --reverse --topo-order --default HEAD \
--parents "$@"
;;
*)
git rev-list --reverse --topo-order --default HEAD \
--parents --full-history "$@" -- "$filter_subdir"
esac > ../revs
commits=$(cat ../revs | wc -l | tr -d " ")
test $commits -eq 0 && die "Found nothing to rewrite"
i=0
while read commit parents; do
i=$(($i+1))
printf "$commit ($i/$commits) "
case "$filter_subdir" in
"")
git read-tree -i -m $commit
;;
*)
git read-tree -i -m $commit:"$filter_subdir"
esac
export GIT_COMMIT=$commit
git cat-file commit "$commit" >../commit
eval "$(set_ident AUTHOR <../commit)"
eval "$(set_ident COMMITTER <../commit)"
eval "$filter_env" < /dev/null
if [ "$filter_tree" ]; then
git checkout-index -f -u -a
# files that $commit removed are now still in the working tree;
# remove them, else they would be added again
git ls-files -z --others | xargs -0 rm -f
eval "$filter_tree" < /dev/null
git diff-index -r $commit | cut -f 2- | tr '\n' '\0' | \
xargs -0 git update-index --add --replace --remove
git ls-files -z --others | \
xargs -0 git update-index --add --replace --remove
fi
eval "$filter_index" < /dev/null
parentstr=
for parent in $parents; do
for reparent in $(map "$parent"); do
parentstr="$parentstr -p $reparent"
done
done
if [ "$filter_parent" ]; then
parentstr="$(echo "$parentstr" | eval "$filter_parent")"
fi
sed -e '1,/^$/d' <../commit | \
eval "$filter_msg" | \
sh -c "$filter_commit" "git commit-tree" $(git write-tree) $parentstr | \
tee ../map/$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
;;
*)
git update-ref refs/heads/"$dstbranch" $target_head
if [ $(cat ../map/$src_head | wc -l) -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
;;
esac
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="$(git rev-parse "$sha1"^{commit} 2>/dev/null)" || continue
fi
[ -f "../map/$sha1" ] || continue
new_sha1="$(cat "../map/$sha1")"
export GIT_COMMIT="$sha1"
new_ref="$(echo "$ref" | eval "$filter_tag_name")"
echo "$ref -> $new_ref ($sha1 -> $new_sha1)"
if [ "$type" = "tag" ]; then
# Warn that we are not rewriting the tag object itself.
warn "unreferencing tag object $sha1t"
fi
git update-ref "refs/tags/$new_ref" "$new_sha1"
done
fi
cd ../..
rm -rf "$tempdir"
echo "Rewritten history saved to the $dstbranch branch"
exit $ret