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Diffstat (limited to 'git-filter-branch.sh')
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diff --git a/git-filter-branch.sh b/git-filter-branch.sh new file mode 100755 index 0000000000..bfd118cd3b --- /dev/null +++ b/git-filter-branch.sh @@ -0,0 +1,433 @@ +#!/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 GIT revision history by creating a new branch from +# your current branch by applying custom filters on each revision. +# Those filters can modify each tree (e.g. removing a file or running +# a perl rewrite on all files) or information about each commit. +# Otherwise, all information (including original commit times or merge +# 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 with 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.) +# +# WARNING! The rewritten history will have different ids for all the +# objects and will not converge with the original branch. You will not +# be able to easily push and distribute the rewritten branch. Please do +# not use this command if you do not know the full implications, and +# avoid using it anyway - do not do what a simple single commit on top +# of the current version would fix. +# +# Always verify that the rewritten version is correct before disposing +# the original branch. +# +# Note that since this operation is extensively I/O expensive, it might +# be a good idea to do it off-disk, e.g. on tmpfs. Reportedly the speedup +# is very noticeable. +# +# OPTIONS +# ------- +# -d TEMPDIR:: The path to the temporary tree used for rewriting +# When applying a tree filter, the command needs to temporary +# checkout the tree to some directory, which may consume +# considerable space in case of large projects. By default it +# does this in the '.git-rewrite/' directory but you can override +# that choice by this parameter. +# +# Filters +# ~~~~~~~ +# The filters are applied in the order as listed below. The COMMAND +# argument is always evaluated in shell using the 'eval' command. +# The $GIT_COMMIT environment variable is permanently set to contain +# the id of the commit being rewritten. The author/committer environment +# variables are set before the first filter is run. +# +# A 'map' function is available that takes an "original sha1 id" argument +# and outputs a "rewritten sha1 id" if the commit has been already +# rewritten, fails otherwise; the 'map' function can return several +# ids on separate lines if your commit filter emitted multiple commits +# (see below). +# +# --env-filter COMMAND:: The filter for modifying environment +# This is the filter for modifying the environment in which +# the commit will be performed. Specifically, you might want +# to rewrite the author/committer name/email/time environment +# variables (see `git-commit` for details). Do not forget to +# re-export the variables. +# +# --tree-filter COMMAND:: The filter for rewriting tree (and its contents) +# This is the filter for rewriting the tree and its contents. +# The COMMAND argument is evaluated in shell with the working +# directory set to the root of the checked out tree. The new tree +# is then used as-is (new files are auto-added, disappeared files +# are auto-removed - .gitignore files nor any other ignore rules +# HAVE NO EFFECT!). +# +# --index-filter COMMAND:: The filter for rewriting index +# This is the filter for rewriting the Git's directory index. +# It is similar to the tree filter but does not check out the +# tree, which makes it much faster. However, you must use the +# lowlevel Git index manipulation commands to do your work. +# +# --parent-filter COMMAND:: The filter for rewriting parents +# This is the filter for rewriting the commit's parent list. +# It will receive the parent string on stdin and shall output +# the new parent string on stdout. The parent string is in +# format accepted by `git-commit-tree`: empty for initial +# commit, "-p parent" for a normal commit and "-p parent1 +# -p parent2 -p parent3 ..." for a merge commit. +# +# --msg-filter COMMAND:: The filter for rewriting commit message +# This is the filter for rewriting the commit messages. +# The COMMAND argument is evaluated in shell with the original +# commit message on standard input; its standard output is +# is used as the new commit message. +# +# --commit-filter COMMAND:: The filter for performing the commit +# If this filter is passed, it will be called instead of the +# `git-commit-tree` command, with those arguments: +# +# TREE_ID [-p PARENT_COMMIT_ID]... +# +# and the log message on stdin. The commit id is expected on +# stdout. As a special extension, the commit filter may emit +# multiple commit ids; in that case, all of them will be used +# as parents instead of the original commit in further commits. +# +# --tag-name-filter COMMAND:: The filter for rewriting tag names. +# If this filter is passed, it will be called for every tag ref +# that points to a rewritten object (or to a tag object which +# points to a rewritten object). The original tag name is passed +# via standard input, and the new tag name is expected on standard +# output. +# +# The original tags are not deleted, but can be overwritten; +# use "--tag-name-filter=cat" to simply update the tags. In this +# case, be very careful and make sure you have the old tags +# backed up in case the conversion has run afoul. +# +# Note that there is currently no support for proper rewriting of +# tag objects; in layman terms, if the tag has a message or signature +# attached, the rewritten tag won't have it. Sorry. (It is by +# definition impossible to preserve signatures at any rate, though.) +# +# --subdirectory-filter DIRECTORY:: Only regard the history, as seen by +# the given subdirectory. The result will contain that directory as +# its project root. +# +# EXAMPLE USAGE +# ------------- +# Suppose you want to remove a file (containing confidential information +# or copyright violation) from all commits: +# +# git-filter-branch --tree-filter 'rm filename' newbranch +# +# A significantly faster version: +# +# git-filter-branch --index-filter 'git-update-index --remove filename' newbranch +# +# Now, you will get the rewritten history saved in the branch 'newbranch' +# (your current branch is left untouched). +# +# To "etch-graft" a commit to the revision history (set a commit to be +# the parent of the current initial commit and propagate that): +# +# git-filter-branch --parent-filter sed\ 's/^$/-p graftcommitid/' newbranch +# +# (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 git-merge without common ancestors +# happened). If this is not the case, use: +# +# git-filter-branch --parent-filter 'cat; [ "$GIT_COMMIT" = "COMMIT" ] && echo "-p GRAFTCOMMIT"' newbranch +# +# To remove commits authored by "Darl McBribe" from the history: +# +# git-filter-branch --commit-filter 'if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ]; then shift; while [ -n "$1" ]; do shift; echo "$1"; shift; done; else git-commit-tree "$@"; fi' newbranch +# +# (the shift magic first throws away the tree id and then the -p +# parameters). Note that this handles merges properly! In case Darl +# committed a merge between P1 and P2, it will be propagated properly +# and all children of the merge will become merge commits with P1,P2 +# as their parents instead of the merge commit. +# +# To restrict rewriting to only part of the history, specify a revision +# range in addition to the new branch name. The new branch name will +# point to the top-most revision that a 'git rev-list' of this range +# will print. +# +# Consider this history: +# +# D--E--F--G--H +# / / +# A--B-----C +# +# To rewrite commits D,E,F,G,H, use: +# +# git-filter-branch ... new-H 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 + +# Testsuite: TODO + +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 "$GIT_DIR" in +/*) + ;; +*) + export GIT_DIR="$(pwd)/../../$GIT_DIR" + ;; +esac + +export GIT_INDEX_FILE="$(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 |