git-merge-without-working

   1 #!/bin/bash
   2
   3 set -e
   4
   5 usage() {
   6     printf $"Usage: %s\n" "git merge-without-working REMOTE"
   7     echo $"It merges the commit REMOTE with your current branch, advancing it, without touching your working dir."
   8     echo $"It's useful for constructing the history (say, after an import from RCS) without loosing the current states of your files."
   9 }
  10
  11 if [[ $# != 1 ]]; then
  12     usage
  13     exit 1
  14 fi
  15
  16 case "$1" in
  17     -h|--help|--usage)
  18         usage
  19         exit 0
  20         ;;
  21 esac
  22
  23 # What to merge:
  24 readonly REMOTE="$1"
  25
  26 readonly BASE="$(git merge-base HEAD "$REMOTE")" \
  27     HEAD=
  28 if [[ "$BASE" == "$(git rev-parse "$REMOTE")" ]]; then
  29     echo $"Nothing to do."
  30 elif [[ "$BASE" == "$(git rev-parse HEAD)" ]]; then
  31     echo $"Fast-forward."
  32     git update-ref HEAD "$(git rev-parse "$REMOTE")"
  33 else
  34     printf $"Merging %s ethereally.\n" "$REMOTE"
  35     git read-tree -v -m -i "$BASE" HEAD "$REMOTE"
  36     # The commit message is read from stdin.
  37     git commit-tree "$(git write-tree)" -p HEAD -p "$REMOTE" \
  38         | xargs git update-ref HEAD
  39 fi