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 GIT revision history by creating a new branch from 8# your current branch by applying custom filters on each revision. 9# Those filters can modify each tree (e.g. removing a file or running 10# a perl rewrite on all files) or information about each commit. 11# Otherwise, all information (including original commit times or merge 12# information) will be preserved. 13# 14# The command takes the new branch name as a mandatory argument and 15# the filters as optional arguments. If you specify no filters, the 16# commits will be recommitted without any changes, which would normally 17# have no effect and result with the new branch pointing to the same 18# branch as your current branch. (Nevertheless, this may be useful in 19# the future for compensating for some Git bugs or such, therefore 20# such a usage is permitted.) 21# 22# WARNING! The rewritten history will have different ids for all the 23# objects and will not converge with the original branch. You will not 24# be able to easily push and distribute the rewritten branch. Please do 25# not use this command if you do not know the full implications, and 26# avoid using it anyway - do not do what a simple single commit on top 27# of the current version would fix. 28# 29# Always verify that the rewritten version is correct before disposing 30# the original branch. 31# 32# Note that since this operation is extensively I/O expensive, it might 33# be a good idea to do it off-disk, e.g. on tmpfs. Reportedly the speedup 34# is very noticeable. 35# 36# OPTIONS 37# ------- 38# -d TEMPDIR:: The path to the temporary tree used for rewriting 39# When applying a tree filter, the command needs to temporary 40# checkout the tree to some directory, which may consume 41# considerable space in case of large projects. By default it 42# does this in the '.git-rewrite/' directory but you can override 43# that choice by this parameter. 44# 45# Filters 46# ~~~~~~~ 47# The filters are applied in the order as listed below. The COMMAND 48# argument is always evaluated in shell using the 'eval' command. 49# The $GIT_COMMIT environment variable is permanently set to contain 50# the id of the commit being rewritten. The author/committer environment 51# variables are set before the first filter is run. 52# 53# A 'map' function is available that takes an "original sha1 id" argument 54# and outputs a "rewritten sha1 id" if the commit has been already 55# rewritten, fails otherwise; the 'map' function can return several 56# ids on separate lines if your commit filter emitted multiple commits 57# (see below). 58# 59# --env-filter COMMAND:: The filter for modifying environment 60# This is the filter for modifying the environment in which 61# the commit will be performed. Specifically, you might want 62# to rewrite the author/committer name/email/time environment 63# variables (see `git-commit` for details). Do not forget to 64# re-export the variables. 65# 66# --tree-filter COMMAND:: The filter for rewriting tree (and its contents) 67# This is the filter for rewriting the tree and its contents. 68# The COMMAND argument is evaluated in shell with the working 69# directory set to the root of the checked out tree. The new tree 70# is then used as-is (new files are auto-added, disappeared files 71# are auto-removed - .gitignore files nor any other ignore rules 72# HAVE NO EFFECT!). 73# 74# --index-filter COMMAND:: The filter for rewriting index 75# This is the filter for rewriting the Git's directory index. 76# It is similar to the tree filter but does not check out the 77# tree, which makes it much faster. However, you must use the 78# lowlevel Git index manipulation commands to do your work. 79# 80# --parent-filter COMMAND:: The filter for rewriting parents 81# This is the filter for rewriting the commit's parent list. 82# It will receive the parent string on stdin and shall output 83# the new parent string on stdout. The parent string is in 84# format accepted by `git-commit-tree`: empty for initial 85# commit, "-p parent" for a normal commit and "-p parent1 86# -p parent2 -p parent3 ..." for a merge commit. 87# 88# --msg-filter COMMAND:: The filter for rewriting commit message 89# This is the filter for rewriting the commit messages. 90# The COMMAND argument is evaluated in shell with the original 91# commit message on standard input; its standard output is 92# is used as the new commit message. 93# 94# --commit-filter COMMAND:: The filter for performing the commit 95# If this filter is passed, it will be called instead of the 96# `git-commit-tree` command, with those arguments: 97# 98# TREE_ID [-p PARENT_COMMIT_ID]... 99# 100# and the log message on stdin. The commit id is expected on 101# stdout. As a special extension, the commit filter may emit 102# multiple commit ids; in that case, all of them will be used 103# as parents instead of the original commit in further commits. 104# 105# --tag-name-filter COMMAND:: The filter for rewriting tag names. 106# If this filter is passed, it will be called for every tag ref 107# that points to a rewritten object (or to a tag object which 108# points to a rewritten object). The original tag name is passed 109# via standard input, and the new tag name is expected on standard 110# output. 111# 112# The original tags are not deleted, but can be overwritten; 113# use "--tag-name-filter=cat" to simply update the tags. In this 114# case, be very careful and make sure you have the old tags 115# backed up in case the conversion has run afoul. 116# 117# Note that there is currently no support for proper rewriting of 118# tag objects; in layman terms, if the tag has a message or signature 119# attached, the rewritten tag won't have it. Sorry. (It is by 120# definition impossible to preserve signatures at any rate, though.) 121# 122# EXAMPLE USAGE 123# ------------- 124# Suppose you want to remove a file (containing confidential information 125# or copyright violation) from all commits: 126# 127# git-filter-branch --tree-filter 'rm filename' newbranch 128# 129# A significantly faster version: 130# 131# git-filter-branch --index-filter 'git-update-index --remove filename' newbranch 132# 133# Now, you will get the rewritten history saved in the branch 'newbranch' 134# (your current branch is left untouched). 135# 136# To "etch-graft" a commit to the revision history (set a commit to be 137# the parent of the current initial commit and propagate that): 138# 139# git-filter-branch --parent-filter sed\ 's/^$/-p graftcommitid/' newbranch 140# 141# (if the parent string is empty - therefore we are dealing with the 142# initial commit - add graftcommit as a parent). Note that this assumes 143# history with a single root (that is, no git-merge without common ancestors 144# happened). If this is not the case, use: 145# 146# git-filter-branch --parent-filter 'cat; [ "$GIT_COMMIT" = "COMMIT" ] && echo "-p GRAFTCOMMIT"' newbranch 147# 148# To remove commits authored by "Darl McBribe" from the history: 149# 150# git-filter-branch --commit-filter 'if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ]; then shift; while [ -n "$1" ]; do shift; echo "$1"; shift; done; else git-commit-tree "$@"; fi' newbranch 151# 152# (the shift magic first throws away the tree id and then the -p 153# parameters). Note that this handles merges properly! In case Darl 154# committed a merge between P1 and P2, it will be propagated properly 155# and all children of the merge will become merge commits with P1,P2 156# as their parents instead of the merge commit. 157# 158# To restrict rewriting to only part of the history, specify a revision 159# range in addition to the new branch name. The new branch name will 160# point to the top-most revision that a 'git rev-list' of this range 161# will print. 162# 163# Consider this history: 164# 165# D--E--F--G--H 166# / / 167# A--B-----C 168# 169# To rewrite commits D,E,F,G,H, use: 170# 171# git-filter-branch ... new-H C..H 172# 173# To rewrite commits E,F,G,H, use one of these: 174# 175# git-filter-branch ... new-H C..H --not D 176# git-filter-branch ... new-H D..H --not C 177 178# Testsuite: TODO 179 180set -e 181 182USAGE="git-filter-branch [-d TEMPDIR] [FILTERS] DESTBRANCH [REV-RANGE]" 183. git-sh-setup 184 185map() 186{ 187# if it was not rewritten, take the original 188test -r"$workdir/../map/$1"||echo"$1" 189cat"$workdir/../map/$1" 190} 191 192# When piped a commit, output a script to set the ident of either 193# "author" or "committer 194 195set_ident () { 196 lid="$(echo "$1" | tr "A-Z" "a-z")" 197 uid="$(echo "$1" | tr "a-z" "A-Z")" 198 pick_id_script=' 199 /^'$lid' /{ 200 s/'\''/'\''\\'\'\''/g 201 h 202 s/^'$lid' \([^<]*\) <[^>]*> .*$/\1/ 203 s/'\''/'\''\'\'\''/g 204 s/.*/export GIT_'$uid'_NAME='\''&'\''/p 205 206 g 207 s/^'$lid'[^<]* <\([^>]*\)> .*$/\1/ 208 s/'\''/'\''\'\'\''/g 209 s/.*/export GIT_'$uid'_EMAIL='\''&'\''/p 210 211 g 212 s/^'$lid' [^<]* <[^>]*> \(.*\)$/\1/ 213 s/'\''/'\''\'\'\''/g 214 s/.*/export GIT_'$uid'_DATE='\''&'\''/p 215 216 q 217} 218' 219 220 LANG=C LC_ALL=C sed -ne "$pick_id_script" 221 # Ensure non-empty id name. 222 echo "[ -n\"\$GIT_${uid}_NAME\"] || export GIT_${uid}_NAME=\"\${GIT_${uid}_EMAIL%%@*}\"" 223} 224 225# list all parent's object names for a given commit 226get_parents () { 227 git-rev-list -1 --parents"$1"|sed"s/^[0-9a-f]*//" 228} 229 230tempdir=.git-rewrite 231filter_env= 232filter_tree= 233filter_index= 234filter_parent= 235filter_msg=cat 236filter_commit='git-commit-tree "$@"' 237filter_tag_name= 238while case"$#"in0) usage;;esac 239do 240case"$1"in 241--) 242shift 243break 244;; 245-*) 246;; 247*) 248break; 249esac 250 251# all switches take one argument 252 ARG="$1" 253case"$#"in1) usage ;;esac 254shift 255 OPTARG="$1" 256shift 257 258case"$ARG"in 259-d) 260 tempdir="$OPTARG" 261;; 262--env-filter) 263 filter_env="$OPTARG" 264;; 265--tree-filter) 266 filter_tree="$OPTARG" 267;; 268--index-filter) 269 filter_index="$OPTARG" 270;; 271--parent-filter) 272 filter_parent="$OPTARG" 273;; 274--msg-filter) 275 filter_msg="$OPTARG" 276;; 277--commit-filter) 278 filter_commit="$OPTARG" 279;; 280--tag-name-filter) 281 filter_tag_name="$OPTARG" 282;; 283*) 284 usage 285;; 286esac 287done 288 289dstbranch="$1" 290shift 291test -n"$dstbranch"|| die "missing branch name" 292git-show-ref"refs/heads/$dstbranch"2> /dev/null && 293 die "branch$dstbranchalready exists" 294 295test!-e"$tempdir"|| die "$tempdiralready exists, please remove it" 296mkdir-p"$tempdir/t" 297cd"$tempdir/t" 298workdir="$(pwd)" 299 300case"$GIT_DIR"in 301/*) 302;; 303*) 304export GIT_DIR="$(pwd)/../../$GIT_DIR" 305;; 306esac 307 308export GIT_INDEX_FILE="$(pwd)/../index" 309git-read-tree# seed the index file 310 311ret=0 312 313 314mkdir ../map # map old->new commit ids for rewriting parents 315 316git-rev-list --reverse --topo-order --default HEAD "$@">../revs 317commits=$(cat ../revs | wc -l | tr -d " ") 318 319test$commits-eq0&& die "Found nothing to rewrite" 320 321i=0 322whileread commit;do 323 i=$(($i+1)) 324printf"$commit($i/$commits) " 325 326 git-read-tree -i -m$commit 327 328export GIT_COMMIT=$commit 329 git-cat-file commit "$commit">../commit 330 331eval"$(set_ident AUTHOR <../commit)" 332eval"$(set_ident COMMITTER <../commit)" 333eval"$filter_env"< /dev/null 334 335if["$filter_tree"];then 336 git-checkout-index -f -u -a 337# files that $commit removed are now still in the working tree; 338# remove them, else they would be added again 339 git-ls-files -z --others|xargs-0rm-f 340eval"$filter_tree"< /dev/null 341 git-diff-index -r$commit| cut -f2- |tr'\n''\0'| \ 342xargs-0 git-update-index --add --replace --remove 343 git-ls-files -z --others| \ 344xargs-0 git-update-index --add --replace --remove 345fi 346 347eval"$filter_index"< /dev/null 348 349 parentstr= 350for parent in$(get_parents $commit);do 351for reparent in$(map "$parent");do 352 parentstr="$parentstr-p$reparent" 353done 354done 355if["$filter_parent"];then 356 parentstr="$(echo "$parentstr" | eval "$filter_parent")" 357fi 358 359sed-e'1,/^$/d'<../commit | \ 360eval"$filter_msg"| \ 361 sh -c"$filter_commit" git-commit-tree$(git-write-tree) $parentstr| \ 362tee ../map/$commit 363done<../revs 364 365src_head=$(tail -n 1 ../revs) 366target_head=$(head -n 1 ../map/$src_head) 367case"$target_head"in 368'') 369echo Nothing rewritten 370;; 371*) 372 git-update-ref refs/heads/"$dstbranch"$target_head 373if[$(cat ../map/$src_head | wc -l)-gt1];then 374echo"WARNING: Your commit filter caused the head commit to expand to several rewritten commits. Only the first such commit was recorded as the current$dstbranchhead but you will need to resolve the situation now (probably by manually merging the other commits). These are all the commits:">&2 375sed's/^/ /' ../map/$src_head>&2 376 ret=1 377fi 378;; 379esac 380 381if["$filter_tag_name"];then 382 git-for-each-ref --format='%(objectname) %(objecttype) %(refname)' refs/tags | 383whileread sha1 type ref;do 384 ref="${ref#refs/tags/}" 385# XXX: Rewrite tagged trees as well? 386if["$type"!="commit"-a"$type"!="tag"];then 387continue; 388fi 389 390if["$type"="tag"];then 391# Dereference to a commit 392 sha1t="$sha1" 393 sha1="$(git-rev-parse "$sha1"^{commit} 2>/dev/null)"||continue 394fi 395 396[-f"../map/$sha1"] ||continue 397 new_sha1="$(cat "../map/$sha1")" 398export GIT_COMMIT="$sha1" 399 new_ref="$(echo "$ref" | eval "$filter_tag_name")" 400 401echo"$ref->$new_ref($sha1->$new_sha1)" 402 403if["$type"="tag"];then 404# Warn that we are not rewriting the tag object itself. 405 warn "unreferencing tag object$sha1t" 406fi 407 408 git-update-ref"refs/tags/$new_ref""$new_sha1" 409done 410fi 411 412cd ../.. 413rm-rf"$tempdir" 414echo"Rewritten history saved to the$dstbranchbranch" 415 416exit$ret