svn-merge2git.sh

   1 #!/bin/sh
   2 # Copyright (c) 2008  Benoit Sigoure <tsuna@lrde.epita.fr>
   3 #
   4 # This program is free software: you can redistribute it and/or modify
   5 # it under the terms of the GNU General Public License as published by
   6 # the Free Software Foundation, either version 3 of the License, or
   7 # (at your option) any later version.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License
  15 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
  16
  17 OPTIONS_SPEC="\
  18 svn-merge2git [options] [refspec]
  19 --
  20 a,all      Do the work on all local the branches
  21 n,dry-run  Do the entire processing without actually changing anything
  22 r,remote   Include remote branches (create a local branch for each of them)
  23 v,verbose  Be more verbose
  24 "
  25 SUBDIRECTORY_OK=Yes
  26 . git-sh-setup
  27 cd_to_toplevel
  28
  29 # BRE (Basic RegExp) compatible with `git rev-list --grep' and `sed'.  The RE
  30 # *must* capture the revision merged in its first group.
  31 merge_pattern='[Mm]erge.*[0-9][0-9]*:\([0-9][0-9]*\)'
  32
  33 # BRE which is used to exclude matches of $merge_pattern
  34 exclude_pattern='Finish'
  35
  36 me=`basename "$0"`
  37
  38 # fatal <msg>
  39 # -----------
  40 # print <msg> on stderr and exit 1
  41 fatal()
  42 {
  43   die "$me: error: $*"
  44 }
  45
  46 # verb <msg>
  47 # ----------
  48 # Print <msg> when verbose mode is enabled.
  49 verb()
  50 {
  51   $opt_verbose && echo "$*"
  52 }
  53
  54 # find_merge_parent <ref> <merge-line>
  55 # ------------------------------------
  56 # Return (in $merge_parent) the sha1 of the commit that has been merged in by
  57 # <ref>.  <merge-line> must be a line extracted from the commit message of
  58 # <ref> and will be used to extract the SVN revision merged.  For instance, if
  59 # <ref> is a SVN merge of merge-line='Merge -r42:51 in branch foo', this
  60 # function puts the sha1 of r51 in $merge_parent.
  61 find_merge_parent()
  62 {
  63   # Find the first line that matches $merge_pattern, do the substitution and
  64   # quit.  Ignore all the other lines.
  65   sed_tmp="s/.*$merge_pattern.*/\\1/"
  66   svn_merge_parent=`echo "$2" | sed "$sed_tmp"`
  67   case $svn_merge_parent in #(
  68     '' | *[^0-9]*)
  69       fatal "invalid SVN revision '$svn_merge_parent' found in $1";;
  70   esac
  71   verb "  $1 is merging SVN r$svn_merge_parent"
  72   merge_parent=`git rev-list \
  73                  --all \
  74                  --grep="^ *git-svn-id: .*@$svn_merge_parent [-0-9a-f]*\\$"`
  75 }
  76
  77 # create_graft <ref> <merge-parent>
  78 # ---------------------------------
  79 # Add <merge-parent> as 2nd parent of the commit designated by <ref>.
  80 create_graft()
  81 {
  82   # --parents will print $1 along with its current parents.
  83   grafted_commit=`git rev-list -1 --parents "$1"`
  84   rv=$?
  85   test $rv -eq 0 || fatal "git rev-list returned $rv"
  86   graft_merge_parent=$2
  87
  88   case $grafted_commit in #(
  89     *"$graft_merge_parent"*)
  90       #verb "  not grafting commit $1: $graft_merge_parent is already a parent ($grafted_commit)"
  91       return 0;;
  92   esac
  93
  94   #verb "  grafting commit $1: add parent $graft_merge_parent"
  95   $opt_dryrun && return 0
  96   echo >>"$GIT_DIR/info/grafts" \
  97     "$grafted_commit $graft_merge_parent" \
  98   || fatal "Failed to add a graft in $GIT_DIR/info/grafts"
  99 }
 100
 101 # rewrite_history
 102 # ---------------
 103 # Make *all* the grafts part of the actual history.
 104 rewrite_history()
 105 {
 106   $opt_dryrun && return 0
 107   git filter-branch --parent-filter cat -- --all
 108 }
 109
 110 # doit <REF>
 111 # ----------
 112 # Find all the merge mentionned in the commit messages and make them become
 113 # real Git merges.
 114 doit()
 115 {
 116   refspec=$1
 117   verb " >> Processing merges in the history of $refspec"
 118
 119   git rev-list -1 "$refspec" >/dev/null \
 120     || fatal "'$refspec' does not seem to be a valid refspec"
 121
 122   git rev-list --grep="$merge_pattern" "$refspec" \
 123    | while read commit; do
 124      merge_line=`git log -1 "$commit" | sed "/$merge_pattern/!d;//q"`
 125      if $has_exclude \
 126      && echo "$merge_line" | grep -- "$exclude_pattern" >/dev/null; then
 127        verb "  skipping $commit whose log is: $merge_line"
 128        continue
 129      fi
 130      verb "  $commit is a merge commit, log says:
 131   | $merge_line"
 132
 133      find_merge_parent "$commit" "$merge_line"
 134      rv=$?
 135      test $rv -eq 0 || exit $rv
 136
 137      case $merge_parent in #(
 138        '' | *[^0-9a-f]*)
 139          fatal "invalid merge_parent: '$merge_parent'";;
 140      esac
 141
 142      create_graft "$commit" "$merge_parent"
 143   done
 144   rv=$?
 145   test $rv -eq 0 || exit $rv
 146 }
 147
 148 # ------------------ #
 149 # `main' starts here #
 150 # ------------------ #
 151
 152 # Parse the options passed to the script.
 153 # Initialize the defaults
 154 opt_all=false
 155 opt_dryrun=false
 156 opt_remote=false
 157 opt_verbose=false
 158
 159 while test $# != 0
 160 do
 161   case $1 in #(
 162     -a | --all)
 163       opt_all=:;; #(
 164     -n | --dry-run)
 165       opt_dryrun=:;; #(
 166     -r | --remote)
 167       opt_remote=:;; #(
 168     -v | --verbose)
 169       opt_verbose=:;; #(
 170     --)
 171       shift; break;; #(
 172     -*)
 173       usage;; #(
 174   esac
 175   shift
 176 done
 177
 178 if $opt_all; then
 179   for line in `git for-each-ref --shell --format='ref=%(refname)' refs/heads`
 180   do
 181     eval "$line"
 182     set "$@" "$ref"
 183   done
 184 fi
 185
 186 if $opt_remote; then
 187   for line in `git for-each-ref --shell --format='ref=%(refname)' refs/remotes`
 188   do
 189     eval "$line"
 190     branch=`basename "$ref"`
 191     case $branch in #(
 192       HEAD) # Skip branches named `HEAD' (which does happen)
 193         continue;; # because they create ambiguities.
 194     esac
 195     # if the local $branch does not already exist, we create one
 196     exists=`git rev-list -1 refs/heads/"$branch" 2>/dev/null`
 197     if test -z "$exists"; then # the $branch does not locally exist
 198       verb "creating branch '$branch' from '$ref'"
 199       git branch "$branch" "$ref" \
 200         || fatal "could not create branch '$branch' from '$ref'"
 201     else # there already is a local $branch
 202       sha1=`git rev-list -1 "$ref"`
 203       # Maybe the existing local $branch is identical to the remote $ref?
 204       if test "$sha1" = "$exists"; then # OK, local = remote
 205         verb "branch '$branch' is already properly initialized to '$ref'"
 206         set "$@" "refs/heads/$branch"
 207       else # KO, local != remote
 208         cat <<EOF
 209 $me: warning: there already exists a local branch '$branch'
 210 and it is at $exists whereas the remote branch '$ref'
 211 is at $sha1 so I'm skipping it...
 212 EOF
 213       fi
 214     fi
 215   done
 216 fi
 217
 218 # No refspec given => work on HEAD
 219 test -z "$*" && set HEAD
 220
 221 if test -z "$exclude_pattern"; then
 222   has_exclude=false
 223 else
 224   has_exclude=:
 225 fi
 226
 227 for refspec
 228 do
 229   doit "$refspec"
 230   echo ">>> processed $refspec"
 231 done
 232
 233 rewrite_history