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# -r STARTREV:: The commit id to start the rewrite at 46# Normally, the command will rewrite the entire history. If you 47# pass this argument, though, this will be the first commit it 48# will rewrite and keep the previous commits intact. 49# 50# -k KEEPREV:: A commit id until which _not_ to rewrite history 51# If you pass this argument, this commit and all of its 52# predecessors are kept intact. 53# 54# Filters 55# ~~~~~~~ 56# The filters are applied in the order as listed below. The COMMAND 57# argument is always evaluated in shell using the 'eval' command. 58# The $GIT_COMMIT environment variable is permanently set to contain 59# the id of the commit being rewritten. The author/committer environment 60# variables are set before the first filter is run. 61# 62# A 'map' function is available that takes an "original sha1 id" argument 63# and outputs a "rewritten sha1 id" if the commit has been already 64# rewritten, fails otherwise; the 'map' function can return several 65# ids on separate lines if your commit filter emitted multiple commits 66# (see below). 67# 68# --env-filter COMMAND:: The filter for modifying environment 69# This is the filter for modifying the environment in which 70# the commit will be performed. Specifically, you might want 71# to rewrite the author/committer name/email/time environment 72# variables (see `git-commit` for details). Do not forget to 73# re-export the variables. 74# 75# --tree-filter COMMAND:: The filter for rewriting tree (and its contents) 76# This is the filter for rewriting the tree and its contents. 77# The COMMAND argument is evaluated in shell with the working 78# directory set to the root of the checked out tree. The new tree 79# is then used as-is (new files are auto-added, disappeared files 80# are auto-removed - .gitignore files nor any other ignore rules 81# HAVE NO EFFECT!). 82# 83# --index-filter COMMAND:: The filter for rewriting index 84# This is the filter for rewriting the Git's directory index. 85# It is similar to the tree filter but does not check out the 86# tree, which makes it much faster. However, you must use the 87# lowlevel Git index manipulation commands to do your work. 88# 89# --parent-filter COMMAND:: The filter for rewriting parents 90# This is the filter for rewriting the commit's parent list. 91# It will receive the parent string on stdin and shall output 92# the new parent string on stdout. The parent string is in 93# format accepted by `git-commit-tree`: empty for initial 94# commit, "-p parent" for a normal commit and "-p parent1 95# -p parent2 -p parent3 ..." for a merge commit. 96# 97# --msg-filter COMMAND:: The filter for rewriting commit message 98# This is the filter for rewriting the commit messages. 99# The COMMAND argument is evaluated in shell with the original 100# commit message on standard input; its standard output is 101# is used as the new commit message. 102# 103# --commit-filter COMMAND:: The filter for performing the commit 104# If this filter is passed, it will be called instead of the 105# `git-commit-tree` command, with those arguments: 106# 107# TREE_ID [-p PARENT_COMMIT_ID]... 108# 109# and the log message on stdin. The commit id is expected on 110# stdout. As a special extension, the commit filter may emit 111# multiple commit ids; in that case, all of them will be used 112# as parents instead of the original commit in further commits. 113# 114# --tag-name-filter COMMAND:: The filter for rewriting tag names. 115# If this filter is passed, it will be called for every tag ref 116# that points to a rewritten object (or to a tag object which 117# points to a rewritten object). The original tag name is passed 118# via standard input, and the new tag name is expected on standard 119# output. 120# 121# The original tags are not deleted, but can be overwritten; 122# use "--tag-name-filter=cat" to simply update the tags. In this 123# case, be very careful and make sure you have the old tags 124# backed up in case the conversion has run afoul. 125# 126# Note that there is currently no support for proper rewriting of 127# tag objects; in layman terms, if the tag has a message or signature 128# attached, the rewritten tag won't have it. Sorry. (It is by 129# definition impossible to preserve signatures at any rate, though.) 130# 131# EXAMPLE USAGE 132# ------------- 133# Suppose you want to remove a file (containing confidential information 134# or copyright violation) from all commits: 135# 136# git-filter-branch --tree-filter 'rm filename' newbranch 137# 138# A significantly faster version: 139# 140# git-filter-branch --index-filter 'git-update-index --remove filename' newbranch 141# 142# Now, you will get the rewritten history saved in the branch 'newbranch' 143# (your current branch is left untouched). 144# 145# To "etch-graft" a commit to the revision history (set a commit to be 146# the parent of the current initial commit and propagate that): 147# 148# git-filter-branch --parent-filter sed\ 's/^$/-p graftcommitid/' newbranch 149# 150# (if the parent string is empty - therefore we are dealing with the 151# initial commit - add graftcommit as a parent). Note that this assumes 152# history with a single root (that is, no git-merge without common ancestors 153# happened). If this is not the case, use: 154# 155# git-filter-branch --parent-filter 'cat; [ "$GIT_COMMIT" = "COMMIT" ] && echo "-p GRAFTCOMMIT"' newbranch 156# 157# To remove commits authored by "Darl McBribe" from the history: 158# 159# git-filter-branch --commit-filter 'if [ "$GIT_AUTHOR_NAME" = "Darl McBribe" ]; then shift; while [ -n "$1" ]; do shift; echo "$1"; shift; done; else git-commit-tree "$@"; fi' newbranch 160# 161# (the shift magic first throws away the tree id and then the -p 162# parameters). Note that this handles merges properly! In case Darl 163# committed a merge between P1 and P2, it will be propagated properly 164# and all children of the merge will become merge commits with P1,P2 165# as their parents instead of the merge commit. 166# 167# To restrict rewriting to only part of the history, use -r or -k or both. 168# Consider this history: 169# 170# D--E--F--G--H 171# / / 172# A--B-----C 173# 174# To rewrite only commits F,G,H, use: 175# 176# git-filter-branch -r F ... 177# 178# To rewrite commits E,F,G,H, use one of these: 179# 180# git-filter-branch -r E -k C ... 181# git-filter-branch -k D -k C ... 182 183# Testsuite: TODO 184 185set -e 186 187USAGE="git-filter-branch [-d TEMPDIR] [-r STARTREV]... [-k KEEPREV]... [-s SRCBRANCH] [FILTERS] DESTBRANCH" 188. git-sh-setup 189 190map() 191{ 192[-r"$workdir/../map/$1"] ||return1 193cat"$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} 228 229# list all parent's object names for a given commit 230get_parents () { 231 git-rev-list -1 --parents"$1"|sed"s/^[0-9a-f]*//" 232} 233 234tempdir=.git-rewrite 235unchanged=" " 236filter_env= 237filter_tree= 238filter_index= 239filter_parent= 240filter_msg=cat 241filter_commit='git-commit-tree "$@"' 242filter_tag_name= 243srcbranch=HEAD 244while case"$#"in0) usage;;esac 245do 246case"$1"in 247--) 248shift 249break 250;; 251-*) 252;; 253*) 254break; 255esac 256 257# all switches take one argument 258 ARG="$1" 259case"$#"in1) usage ;;esac 260shift 261 OPTARG="$1" 262shift 263 264case"$ARG"in 265-d) 266 tempdir="$OPTARG" 267;; 268-r) 269 unchanged="$(get_parents "$OPTARG")$unchanged" 270;; 271-k) 272 unchanged="$(git-rev-parse "$OPTARG"^{commit})$unchanged" 273;; 274--env-filter) 275 filter_env="$OPTARG" 276;; 277--tree-filter) 278 filter_tree="$OPTARG" 279;; 280--index-filter) 281 filter_index="$OPTARG" 282;; 283--parent-filter) 284 filter_parent="$OPTARG" 285;; 286--msg-filter) 287 filter_msg="$OPTARG" 288;; 289--commit-filter) 290 filter_commit="$OPTARG" 291;; 292--tag-name-filter) 293 filter_tag_name="$OPTARG" 294;; 295-s) 296 srcbranch="$OPTARG" 297;; 298*) 299 usage 300;; 301esac 302done 303 304dstbranch="$1" 305test -n"$dstbranch"|| die "missing branch name" 306git-show-ref"refs/heads/$dstbranch"2> /dev/null && 307 die "branch$dstbranchalready exists" 308 309test!-e"$tempdir"|| die "$tempdiralready exists, please remove it" 310mkdir-p"$tempdir/t" 311cd"$tempdir/t" 312workdir="$(pwd)" 313 314case"$GIT_DIR"in 315/*) 316;; 317*) 318export GIT_DIR="$(pwd)/../../$GIT_DIR" 319;; 320esac 321 322export GIT_INDEX_FILE="$(pwd)/../index" 323git-read-tree# seed the index file 324 325ret=0 326 327 328mkdir ../map # map old->new commit ids for rewriting parents 329 330# seed with identity mappings for the parents where we start off 331for commit in$unchanged;do 332echo$commit> ../map/$commit 333done 334 335git-rev-list --reverse --topo-order$srcbranch--not$unchanged>../revs 336commits=$(cat ../revs | wc -l | tr -d " ") 337 338test$commits-eq0&& die "Found nothing to rewrite" 339 340i=0 341whileread commit;do 342 i=$((i+1)) 343printf"$commit($i/$commits) " 344 345 git-read-tree -i -m$commit 346 347export GIT_COMMIT=$commit 348 git-cat-file commit "$commit">../commit 349 350eval"$(set_ident AUTHOR <../commit)" 351eval"$(set_ident COMMITTER <../commit)" 352eval"$filter_env"< /dev/null 353 354if["$filter_tree"];then 355 git-checkout-index -f -u -a 356# files that $commit removed are now still in the working tree; 357# remove them, else they would be added again 358 git-ls-files -z --others|xargs-0rm-f 359eval"$filter_tree"< /dev/null 360 git-diff-index -r$commit| cut -f2- |tr'\n''\0'| \ 361xargs-0 git-update-index --add --replace --remove 362 git-ls-files -z --others| \ 363xargs-0 git-update-index --add --replace --remove 364fi 365 366eval"$filter_index"< /dev/null 367 368 parentstr= 369for parent in$(get_parents $commit);do 370if[-r"../map/$parent"];then 371for reparent in$(cat "../map/$parent");do 372 parentstr="$parentstr-p$reparent" 373done 374else 375 die "assertion failed: parent$parentfor commit$commitnot found in rewritten ones" 376fi 377done 378if["$filter_parent"];then 379 parentstr="$(echo "$parentstr" | eval "$filter_parent")" 380fi 381 382sed-e'1,/^$/d'<../commit | \ 383eval"$filter_msg"| \ 384 sh -c"$filter_commit" git-commit-tree$(git-write-tree) $parentstr| \ 385tee ../map/$commit 386done<../revs 387 388git-update-ref refs/heads/"$dstbranch"$(head -n 1 ../map/$(tail -n 1 ../revs)) 389if["$(cat ../map/$(tail -n 1 ../revs)| wc -l)"-gt1];then 390echo"WARNING: Your commit filter caused the head commit to expand to several rewritten commits. Only the first such commit was recorded as the current$dstbranchhead but you will need to resolve the situation now (probably by manually merging the other commits). These are all the commits:">&2 391sed's/^/ /' ../map/$(tail -n 1 ../revs)>&2 392 ret=1 393fi 394 395if["$filter_tag_name"];then 396 git-for-each-ref --format='%(objectname) %(objecttype) %(refname)' refs/tags | 397whileread sha1 type ref;do 398 ref="${ref#refs/tags/}" 399# XXX: Rewrite tagged trees as well? 400if["$type"!="commit"-a"$type"!="tag"];then 401continue; 402fi 403 404if["$type"="tag"];then 405# Dereference to a commit 406 sha1t="$sha1" 407 sha1="$(git-rev-parse "$sha1"^{commit} 2>/dev/null)"||continue 408fi 409 410[-f"../map/$sha1"] ||continue 411 new_sha1="$(cat "../map/$sha1")" 412export GIT_COMMIT="$sha1" 413 new_ref="$(echo "$ref" | eval "$filter_tag_name")" 414 415echo"$ref->$new_ref($sha1->$new_sha1)" 416 417if["$type"="tag"];then 418# Warn that we are not rewriting the tag object itself. 419 warn "unreferencing tag object$sha1t" 420fi 421 422 git-update-ref"refs/tags/$new_ref""$new_sha1" 423done 424fi 425 426cd ../.. 427rm-rf"$tempdir" 428echo"Rewritten history saved to the$dstbranchbranch" 429 430exit$ret