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# Testsuite: TODO 183 184set -e 185 186USAGE="git-filter-branch [-d TEMPDIR] [FILTERS] DESTBRANCH [REV-RANGE]" 187. git-sh-setup 188 189map() 190{ 191# if it was not rewritten, take the original 192test -r"$workdir/../map/$1"||echo"$1" 193cat"$workdir/../map/$1" 194} 195 196# When piped a commit, output a script to set the ident of either 197# "author" or "committer 198 199set_ident () { 200 lid="$(echo "$1" | tr "A-Z" "a-z")" 201 uid="$(echo "$1" | tr "a-z" "A-Z")" 202 pick_id_script=' 203 /^'$lid' /{ 204 s/'\''/'\''\\'\'\''/g 205 h 206 s/^'$lid' \([^<]*\) <[^>]*> .*$/\1/ 207 s/'\''/'\''\'\'\''/g 208 s/.*/export GIT_'$uid'_NAME='\''&'\''/p 209 210 g 211 s/^'$lid'[^<]* <\([^>]*\)> .*$/\1/ 212 s/'\''/'\''\'\'\''/g 213 s/.*/export GIT_'$uid'_EMAIL='\''&'\''/p 214 215 g 216 s/^'$lid' [^<]* <[^>]*> \(.*\)$/\1/ 217 s/'\''/'\''\'\'\''/g 218 s/.*/export GIT_'$uid'_DATE='\''&'\''/p 219 220 q 221} 222' 223 224 LANG=C LC_ALL=C sed -ne "$pick_id_script" 225 # Ensure non-empty id name. 226 echo "[ -n\"\$GIT_${uid}_NAME\"] || export GIT_${uid}_NAME=\"\${GIT_${uid}_EMAIL%%@*}\"" 227} 228 229tempdir=.git-rewrite 230filter_env= 231filter_tree= 232filter_index= 233filter_parent= 234filter_msg=cat 235filter_commit='git-commit-tree"$@"' 236filter_tag_name= 237filter_subdir= 238while case "$#" in 0) usage;; esac 239do 240 case "$1" in 241 --) 242 shift 243 break 244 ;; 245 -*) 246 ;; 247 *) 248 break; 249 esac 250 251 # all switches take one argument 252 ARG="$1" 253 case "$#" in 1) usage ;; esac 254 shift 255 OPTARG="$1" 256 shift 257 258 case "$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 --subdirectory-filter) 284 filter_subdir="$OPTARG" 285 ;; 286 *) 287 usage 288 ;; 289 esac 290done 291 292dstbranch="$1" 293shift 294test -n "$dstbranch" || die "missing branch name" 295git-show-ref "refs/heads/$dstbranch" 2> /dev/null && 296 die "branch$dstbranchalready exists" 297 298test ! -e "$tempdir" || die "$tempdiralready exists, please remove it" 299mkdir -p "$tempdir/t" 300cd "$tempdir/t" 301workdir="$(pwd)" 302 303case "$GIT_DIR" in 304/*) 305 ;; 306*) 307 export GIT_DIR="$(pwd)/../../$GIT_DIR" 308 ;; 309esac 310 311export GIT_INDEX_FILE="$(pwd)/../index" 312git-read-tree # seed the index file 313 314ret=0 315 316 317mkdir ../map # map old->new commit ids for rewriting parents 318 319case "$filter_subdir" in 320"") 321 git-rev-list --reverse --topo-order --default HEAD \ 322 --parents "$@" 323 ;; 324*) 325 git-rev-list --reverse --topo-order --default HEAD \ 326 --parents "$@" -- "$filter_subdir" 327esac > ../revs 328commits=$(cat ../revs | wc -l | tr -d " ") 329 330test$commits-eq 0 && die "Found nothing to rewrite" 331 332i=0 333while read commit parents; do 334 i=$(($i+1)) 335 printf "$commit($i/$commits) " 336 337 case "$filter_subdir" in 338 "") 339 git-read-tree -i -m$commit 340 ;; 341 *) 342 git-read-tree -i -m$commit:"$filter_subdir" 343 esac 344 345 export GIT_COMMIT=$commit 346 git-cat-file commit "$commit" >../commit 347 348 eval "$(set_ident AUTHOR <../commit)" 349 eval "$(set_ident COMMITTER <../commit)" 350 eval "$filter_env" < /dev/null 351 352 if [ "$filter_tree" ]; then 353 git-checkout-index -f -u -a 354 # files that$commitremoved are now still in the working tree; 355 # remove them, else they would be added again 356 git-ls-files -z --others | xargs -0 rm -f 357 eval "$filter_tree" < /dev/null 358 git-diff-index -r$commit| cut -f 2- | tr '\n' '\0' | \ 359 xargs -0 git-update-index --add --replace --remove 360 git-ls-files -z --others | \ 361 xargs -0 git-update-index --add --replace --remove 362 fi 363 364 eval "$filter_index" < /dev/null 365 366 parentstr= 367 for parent in$parents; do 368 for reparent in$(map "$parent"); do 369 parentstr="$parentstr-p$reparent" 370 done 371 done 372 if [ "$filter_parent" ]; then 373 parentstr="$(echo "$parentstr" | eval "$filter_parent")" 374 fi 375 376 sed -e '1,/^$/d' <../commit | \ 377 eval "$filter_msg" | \ 378 sh -c "$filter_commit" git-commit-tree$(git-write-tree)$parentstr| \ 379 tee ../map/$commit 380done <../revs 381 382src_head=$(tail -n 1 ../revs | sed -e 's/ .*//') 383target_head=$(head -n 1 ../map/$src_head) 384case "$target_head" in 385'') 386 echo Nothing rewritten 387 ;; 388*) 389 git-update-ref refs/heads/"$dstbranch"$target_head 390 if [$(cat ../map/$src_head | wc -l)-gt 1 ]; then 391 echo "WARNING: Your commit filter caused the head commit to expand to several rewritten commits. Only the first such commit was recorded as the current$dstbranchhead but you will need to resolve the situation now (probably by manually merging the other commits). These are all the commits:" >&2 392 sed 's/^/ /' ../map/$src_head>&2 393 ret=1 394 fi 395 ;; 396esac 397 398if [ "$filter_tag_name" ]; then 399 git-for-each-ref --format='%(objectname) %(objecttype) %(refname)' refs/tags | 400 while read sha1 type ref; do 401 ref="${ref#refs/tags/}" 402 # XXX: Rewrite tagged trees as well? 403 if [ "$type" != "commit" -a "$type" != "tag" ]; then 404 continue; 405 fi 406 407 if [ "$type" = "tag" ]; then 408 # Dereference to a commit 409 sha1t="$sha1" 410 sha1="$(git-rev-parse "$sha1"^{commit} 2>/dev/null)" || continue 411 fi 412 413 [ -f "../map/$sha1" ] || continue 414 new_sha1="$(cat "../map/$sha1")" 415 export GIT_COMMIT="$sha1" 416 new_ref="$(echo "$ref" | eval "$filter_tag_name")" 417 418 echo "$ref->$new_ref($sha1->$new_sha1)" 419 420 if [ "$type" = "tag" ]; then 421 # Warn that we are not rewriting the tag object itself. 422 warn "unreferencing tag object$sha1t" 423 fi 424 425 git-update-ref "refs/tags/$new_ref" "$new_sha1" 426 done 427fi 428 429cd ../.. 430rm -rf "$tempdir" 431echo "Rewritten history saved to the$dstbranchbranch" 432 433exit$ret