share/msysGit/merging-rebase.sh

   1 #!/bin/sh
   2 #
   3 # Rebase 'master' on top of an upstream branch (defaults to 'junio/next'),
   4 # retaining "fast-forwardability" by "merging" (with the "ours" strategy) the
   5 # previous state on top of the current upstream state.
   6 #
   7 # options:
   8 #  --dry-run
   9 #     do not perform the rebase but only display the revisions selected
  10 #
  11 #  --graph
  12 #     as for dry-run but display the commits as a graph
  13 #
  14 #  --cherry
  15 #     as for --dry-run but display the commits using cherry notation to mark
  16 #     commits that are suitable for upstream consideration.
  17
  18 force=
  19 dryrun=
  20 graph=
  21 cherry=
  22 while test $# -gt 0
  23 do
  24         case "$1" in
  25         -f|--force)
  26                 force=--force
  27                 ;;
  28         -s|--show|-d|--dry-run)
  29                 dryrun=t
  30                 ;;
  31         -g|--graph)
  32                 dryrun=t
  33                 graph=--graph
  34                 ;;
  35         -c|--cherry)
  36                 dryrun=t
  37                 cherry=--cherry
  38                 ;;
  39         -h|--help)
  40                 cat >&2 << EOF
  41 Usage: $0 [options] [<upstream>]
  42
  43 Options:
  44 -s|--show       show which commits would be cherry-picked
  45 -g|--graph      like --show, but with the commit graph
  46 -c|--cherry     try to leave out commits that were applied upstream
  47 EOF
  48                 exit 1
  49                 ;;
  50         -*)
  51                 echo "Unknown option: $1" >&2
  52                 exit 1
  53                 ;;
  54         *)
  55                 break
  56                 ;;
  57         esac
  58         shift
  59 done
  60
  61 TO=${1:-junio/next}
  62
  63 if test -z "$force" && test -z "$(git rev-list .."$TO")"
  64 then
  65         echo "Nothing new in $TO; To force a rebase, use the --force, Luke!" >&2
  66         exit 1
  67 fi
  68
  69 HEAD_NAME="$(git rev-parse --symbolic-full-name HEAD)"
  70 case "$HEAD_NAME" in
  71 refs/heads/*)
  72         UPSTREAM=$(git rev-parse --symbolic-full-name HEAD@{u}) || {
  73                 echo "Not tracking any remote branch!" >&2
  74                 exit 1
  75         }
  76         test "$(git rev-parse HEAD)" = "$(git rev-parse $UPSTREAM)" ||
  77         test "$(git rev-parse $HEAD_NAME@{1})" = "$(git rev-parse $UPSTREAM)" || {
  78                 echo "Your '$HEAD_NAME' is not up-to-date!" >&2
  79                 exit 1
  80         }
  81         ;; # okay
  82 HEAD) ;; # okay
  83 *)
  84         echo "Not on any branch!" >&2
  85         exit 1
  86         ;;
  87 esac
  88 FROM_SHA1=$(git rev-parse --short HEAD)
  89 TO_SHA1=$(git rev-parse --short $TO)
  90
  91 is_ours_merge () {
  92         test "$(git rev-parse $1:)" = "$(git rev-parse "$1^:")"
  93 }
  94
  95 list_merges () {
  96         git rev-list --parents "$@" | sed -n 's/ .* .*//p'
  97 }
  98
  99 # Find old merging rebase, if any
 100
 101 REBASING_BASE=
 102 for commit in $(list_merges $TO..)
 103 do
 104         if is_ours_merge $commit
 105         then
 106                 subject="$(git show -s --format=%s $commit)"
 107                 case "$subject" in
 108                 *merging-rebase*) ;;
 109                 *)
 110                         printf "%s\n\n%s\n%s\n\n(y/n) " \
 111                                 "Is this the latest merging rebase?" \
 112                                 $commit "$subject"
 113                         read answer
 114                         case "$answer" in
 115                         y*|Y*) ;;
 116                         *) continue;;
 117                         esac;;
 118                 esac
 119                 REBASING_BASE=$commit
 120                 break
 121         fi
 122 done
 123
 124 BASE_MESSAGE=
 125 if test -n "$REBASING_BASE"
 126 then
 127         BASE_MESSAGE="using $REBASING_BASE as base."
 128         MESSAGE="$(git cat-file commit $REBASING_BASE |
 129                 sed '1,/^$/d')"
 130         # old style rebasing merge?
 131         case "$MESSAGE" in
 132         "Rebasing merge to "*)
 133                 BASE_MESSAGE="using the rebasing merge $REBASING_BASE."
 134                 # Fake a commit such that 'git log <commit>..' shows all the
 135                 # commits we want to rebase
 136                 PREVIOUS_REBASING="$(git rev-parse $REBASING_BASE^2)"
 137                 PREVIOUS_ONTO="$(echo "$MESSAGE" |
 138                         sed -n '1s/Rebasing merge .*(\(.*\))/\1/p')"
 139                 # To avoid checking out unneeded files/file versions, the
 140                 # throw-away base points to the tree we want to rebase onto
 141                 REBASING_BASE="$(echo Dummy |
 142                         git commit-tree $TO_SHA1: \
 143                                 -p $PREVIOUS_ONTO -p $PREVIOUS_REBASING)"
 144                 ;;
 145         esac
 146 fi
 147
 148 RANGE=$REBASING_BASE..
 149 if test -n "$dryrun"
 150 then
 151         git log --oneline $graph $cherry --boundary $RANGE
 152         exit
 153 fi
 154
 155 exec "$(dirname "$0")"/shears.sh $force --merging --onto=$TO ${REBASING_BASE:-$TO}