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# --subdirectory-filter DIRECTORY:: Only regard the history, as seen by 123# the given subdirectory. The result will contain that directory as 124# its project root. 125# 126# EXAMPLE USAGE 127# ------------- 128# Suppose you want to remove a file (containing confidential information 129# or copyright violation) from all commits: 130# 131# git-filter-branch --tree-filter 'rm filename' newbranch 132# 133# A significantly faster version: 134# 135# git-filter-branch --index-filter 'git-update-index --remove filename' newbranch 136# 137# Now, you will get the rewritten history saved in the branch 'newbranch' 138# (your current branch is left untouched). 139# 140# To "etch-graft" a commit to the revision history (set a commit to be 141# the parent of the current initial commit and propagate that): 142# 143# git-filter-branch --parent-filter sed\ 's/^$/-p graftcommitid/' newbranch 144# 145# (if the parent string is empty - therefore we are dealing with the 146# initial commit - add graftcommit as a parent). Note that this assumes 147# history with a single root (that is, no git-merge without common ancestors 148# happened). If this is not the case, use: 149# 150# git-filter-branch --parent-filter 'cat; [ "$GIT_COMMIT" = "COMMIT" ] && echo "-p GRAFTCOMMIT"' newbranch 151# 152# To remove commits authored by "Darl McBribe" from the history: 153# 154# git-filter-branch --commit-filter 'if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ]; then shift; while [ -n "$1" ]; do shift; echo "$1"; shift; done; else git-commit-tree "$@"; fi' newbranch 155# 156# (the shift magic first throws away the tree id and then the -p 157# parameters). Note that this handles merges properly! In case Darl 158# committed a merge between P1 and P2, it will be propagated properly 159# and all children of the merge will become merge commits with P1,P2 160# as their parents instead of the merge commit. 161# 162# To restrict rewriting to only part of the history, specify a revision 163# range in addition to the new branch name. The new branch name will 164# point to the top-most revision that a 'git rev-list' of this range 165# will print. 166# 167# Consider this history: 168# 169# D--E--F--G--H 170# / / 171# A--B-----C 172# 173# To rewrite commits D,E,F,G,H, use: 174# 175# git-filter-branch ... new-H C..H 176# 177# To rewrite commits E,F,G,H, use one of these: 178# 179# git-filter-branch ... new-H C..H --not D 180# git-filter-branch ... new-H D..H --not C 181# 182# To move the whole tree into a subdirectory, or remove it from there: 183# 184# git-filter-branch --index-filter \ 185# 'git-ls-files -s | sed "s-\t-&newsubdir/-" | 186# GIT_INDEX_FILE=$GIT_INDEX_FILE.new \ 187# git-update-index --index-info && 188# mv $GIT_INDEX_FILE.new $GIT_INDEX_FILE' directorymoved 189 190# Testsuite: TODO 191 192set -e 193 194USAGE="git-filter-branch [-d TEMPDIR] [FILTERS] DESTBRANCH [REV-RANGE]" 195. git-sh-setup 196 197map() 198{ 199# if it was not rewritten, take the original 200test -r"$workdir/../map/$1"||echo"$1" 201cat"$workdir/../map/$1" 202} 203 204# When piped a commit, output a script to set the ident of either 205# "author" or "committer 206 207set_ident () { 208 lid="$(echo "$1" | tr "A-Z" "a-z")" 209 uid="$(echo "$1" | tr "a-z" "A-Z")" 210 pick_id_script=' 211 /^'$lid' /{ 212 s/'\''/'\''\\'\'\''/g 213 h 214 s/^'$lid' \([^<]*\) <[^>]*> .*$/\1/ 215 s/'\''/'\''\'\'\''/g 216 s/.*/export GIT_'$uid'_NAME='\''&'\''/p 217 218 g 219 s/^'$lid'[^<]* <\([^>]*\)> .*$/\1/ 220 s/'\''/'\''\'\'\''/g 221 s/.*/export GIT_'$uid'_EMAIL='\''&'\''/p 222 223 g 224 s/^'$lid' [^<]* <[^>]*> \(.*\)$/\1/ 225 s/'\''/'\''\'\'\''/g 226 s/.*/export GIT_'$uid'_DATE='\''&'\''/p 227 228 q 229} 230' 231 232 LANG=C LC_ALL=C sed -ne "$pick_id_script" 233 # Ensure non-empty id name. 234 echo "[ -n\"\$GIT_${uid}_NAME\"] || export GIT_${uid}_NAME=\"\${GIT_${uid}_EMAIL%%@*}\"" 235} 236 237tempdir=.git-rewrite 238filter_env= 239filter_tree= 240filter_index= 241filter_parent= 242filter_msg=cat 243filter_commit='git-commit-tree"$@"' 244filter_tag_name= 245filter_subdir= 246while case "$#" in 0) usage;; esac 247do 248 case "$1" in 249 --) 250 shift 251 break 252 ;; 253 -*) 254 ;; 255 *) 256 break; 257 esac 258 259 # all switches take one argument 260 ARG="$1" 261 case "$#" in 1) usage ;; esac 262 shift 263 OPTARG="$1" 264 shift 265 266 case "$ARG" in 267 -d) 268 tempdir="$OPTARG" 269 ;; 270 --env-filter) 271 filter_env="$OPTARG" 272 ;; 273 --tree-filter) 274 filter_tree="$OPTARG" 275 ;; 276 --index-filter) 277 filter_index="$OPTARG" 278 ;; 279 --parent-filter) 280 filter_parent="$OPTARG" 281 ;; 282 --msg-filter) 283 filter_msg="$OPTARG" 284 ;; 285 --commit-filter) 286 filter_commit="$OPTARG" 287 ;; 288 --tag-name-filter) 289 filter_tag_name="$OPTARG" 290 ;; 291 --subdirectory-filter) 292 filter_subdir="$OPTARG" 293 ;; 294 *) 295 usage 296 ;; 297 esac 298done 299 300dstbranch="$1" 301shift 302test -n "$dstbranch" || die "missing branch name" 303git-show-ref "refs/heads/$dstbranch" 2> /dev/null && 304 die "branch$dstbranchalready exists" 305 306test ! -e "$tempdir" || die "$tempdiralready exists, please remove it" 307mkdir -p "$tempdir/t" 308cd "$tempdir/t" 309workdir="$(pwd)" 310 311case "$GIT_DIR" in 312/*) 313 ;; 314*) 315 GIT_DIR="$(pwd)/../../$GIT_DIR" 316 ;; 317esac 318export GIT_DIR GIT_WORK_TREE=. 319 320export GIT_INDEX_FILE="$(pwd)/../index" 321git-read-tree # seed the index file 322 323ret=0 324 325 326mkdir ../map # map old->new commit ids for rewriting parents 327 328case "$filter_subdir" in 329"") 330 git-rev-list --reverse --topo-order --default HEAD \ 331 --parents "$@" 332 ;; 333*) 334 git-rev-list --reverse --topo-order --default HEAD \ 335 --parents --full-history "$@" -- "$filter_subdir" 336esac > ../revs 337commits=$(cat ../revs | wc -l | tr -d " ") 338 339test$commits-eq 0 && die "Found nothing to rewrite" 340 341i=0 342while read commit parents; do 343 i=$(($i+1)) 344 printf "$commit($i/$commits) " 345 346 case "$filter_subdir" in 347 "") 348 git-read-tree -i -m$commit 349 ;; 350 *) 351 git-read-tree -i -m$commit:"$filter_subdir" 352 esac 353 354 export GIT_COMMIT=$commit 355 git-cat-file commit "$commit" >../commit 356 357 eval "$(set_ident AUTHOR <../commit)" 358 eval "$(set_ident COMMITTER <../commit)" 359 eval "$filter_env" < /dev/null 360 361 if [ "$filter_tree" ]; then 362 git-checkout-index -f -u -a 363 # files that$commitremoved are now still in the working tree; 364 # remove them, else they would be added again 365 git-ls-files -z --others | xargs -0 rm -f 366 eval "$filter_tree" < /dev/null 367 git-diff-index -r$commit| cut -f 2- | tr '\n' '\0' | \ 368 xargs -0 git-update-index --add --replace --remove 369 git-ls-files -z --others | \ 370 xargs -0 git-update-index --add --replace --remove 371 fi 372 373 eval "$filter_index" < /dev/null 374 375 parentstr= 376 for parent in$parents; do 377 for reparent in$(map "$parent"); do 378 parentstr="$parentstr-p$reparent" 379 done 380 done 381 if [ "$filter_parent" ]; then 382 parentstr="$(echo "$parentstr" | eval "$filter_parent")" 383 fi 384 385 sed -e '1,/^$/d' <../commit | \ 386 eval "$filter_msg" | \ 387 sh -c "$filter_commit" git-commit-tree$(git-write-tree)$parentstr| \ 388 tee ../map/$commit 389done <../revs 390 391src_head=$(tail -n 1 ../revs | sed -e 's/ .*//') 392target_head=$(head -n 1 ../map/$src_head) 393case "$target_head" in 394'') 395 echo Nothing rewritten 396 ;; 397*) 398 git-update-ref refs/heads/"$dstbranch"$target_head 399 if [$(cat ../map/$src_head | wc -l)-gt 1 ]; then 400 echo "WARNING: Your commit filter caused the head commit to expand to several rewritten commits. Only the first such commit was recorded as the current$dstbranchhead but you will need to resolve the situation now (probably by manually merging the other commits). These are all the commits:" >&2 401 sed 's/^/ /' ../map/$src_head>&2 402 ret=1 403 fi 404 ;; 405esac 406 407if [ "$filter_tag_name" ]; then 408 git-for-each-ref --format='%(objectname) %(objecttype) %(refname)' refs/tags | 409 while read sha1 type ref; do 410 ref="${ref#refs/tags/}" 411 # XXX: Rewrite tagged trees as well? 412 if [ "$type" != "commit" -a "$type" != "tag" ]; then 413 continue; 414 fi 415 416 if [ "$type" = "tag" ]; then 417 # Dereference to a commit 418 sha1t="$sha1" 419 sha1="$(git-rev-parse "$sha1"^{commit} 2>/dev/null)" || continue 420 fi 421 422 [ -f "../map/$sha1" ] || continue 423 new_sha1="$(cat "../map/$sha1")" 424 export GIT_COMMIT="$sha1" 425 new_ref="$(echo "$ref" | eval "$filter_tag_name")" 426 427 echo "$ref->$new_ref($sha1->$new_sha1)" 428 429 if [ "$type" = "tag" ]; then 430 # Warn that we are not rewriting the tag object itself. 431 warn "unreferencing tag object$sha1t" 432 fi 433 434 git-update-ref "refs/tags/$new_ref" "$new_sha1" 435 done 436fi 437 438cd ../.. 439rm -rf "$tempdir" 440echo "Rewritten history saved to the$dstbranchbranch" 441 442exit$ret