share/msysGit/merging-rebase.sh

   1 #!/bin/sh
   2 #
   3 # Rebase 'devel' 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=t
  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 $commit
 105         then
 106                 REBASING_BASE=$commit
 107                 break
 108         fi
 109 done
 110
 111 BASE_MESSAGE=
 112 if test -n "$REBASING_BASE"
 113 then
 114         BASE_MESSAGE="using $REBASING_BASE as base."
 115         MESSAGE="$(git cat-file commit $REBASING_BASE |
 116                 sed '1,/^$/d')"
 117         # old style rebasing merge?
 118         case "$MESSAGE" in
 119         "Rebasing merge to "*)
 120                 BASE_MESSAGE="using the rebasing merge $REBASING_BASE."
 121                 # Fake a commit such that 'git log <commit>..' shows all the
 122                 # commits we want to rebase
 123                 PREVIOUS_REBASING="$(git rev-parse $REBASING_BASE^2)"
 124                 PREVIOUS_ONTO="$(echo "$MESSAGE" |
 125                         sed -n '1s/Rebasing merge .*(\(.*\))/\1/p')"
 126                 # To avoid checking out unneeded files/file versions, the
 127                 # throw-away base points to the tree we want to rebase onto
 128                 REBASING_BASE="$(echo Dummy |
 129                         git commit-tree $TO_SHA1: \
 130                                 -p $PREVIOUS_ONTO -p $PREVIOUS_REBASING)"
 131                 ;;
 132         esac
 133 fi
 134
 135 RANGE=$REBASING_BASE..
 136 if test -n "$dryrun"
 137 then
 138         git log --oneline $graph $cherry --boundary $RANGE
 139         exit
 140 fi
 141
 142 # Fake our own editor to inject initial steps into the edit script
 143 TODO_EXTRA="$(git rev-parse --git-dir)/.todo-extra"
 144 printf "%s\n\n%s\n%s" "Start the merging-rebase to $TO" \
 145         "This commit starts the rebase of $FROM_SHA1 to $TO_SHA1" \
 146         "$BASE_MESSAGE" > "$TODO_EXTRA.msg"
 147 cat > "$TODO_EXTRA" << EOF
 148 # Start the merging rebase:
 149 # Reset to $TO and ...
 150 exec git reset --hard $TO
 151 # ... fake-merge current $HEAD_NAME
 152 exec git merge -s ours -m "\$(cat "$TODO_EXTRA.msg")" $FROM_SHA1
 153
 154 # Patches to rebase:
 155 EOF
 156 TMP_EDITOR="$(git rev-parse --git-dir)/.rebasing-editor.sh" &&
 157 cat > "$TMP_EDITOR" << EOF &&
 158 #!/bin/sh
 159 case "\$1" in
 160 */git-rebase-todo)
 161         # prepend the initialising commands
 162         cat "\$1" >> "$TODO_EXTRA" &&
 163         mv "$TODO_EXTRA" "\$1"
 164 esac &&
 165 exec "$(git var GIT_EDITOR)" "\$@"
 166 EOF
 167 chmod a+x "$TMP_EDITOR"
 168
 169 # Rebase!
 170 GIT_EDITOR="$TMP_EDITOR" git rebase --autosquash -i ${REBASING_BASE:-$TO}