git-mread-and-commit

   1 #!/bin/bash
   2
   3 set -e
   4
   5 # How to refer to the new commit:
   6 readonly TAG="$1"
   7 shift
   8
   9 parent_opts=()
  10 # We don't want to commit with current time, we want to commit with a time that is a function of the RCS content (actually, max), because this makes this command idempotent.
  11 time=0
  12
  13 single-read() {
  14     git read-tree -v "$@" "$parent"
  15     parent_opts+=(-p "$parent")
  16     # Keep the max time for the future commit:
  17     local newtime="$(git show "$parent" --pretty=format:'%ct' | head -1)"
  18     if (( newtime > time )); then time="$newtime"; fi
  19 }
  20
  21 # First time, we should save the old index and start reading new stuff into it:
  22 printf $"%s is saving your current index.\n" "$0"
  23 readonly SAVED_INDEX="$(git write-tree)"
  24 restore_index() {
  25     printf $"%s is restoring your old index.\n" "$0"
  26     git read-tree -v  "$SAVED_INDEX"
  27 }
  28 trap restore_index EXIT # Yes, it will be executed when exiting after an error as well (checked).
  29
  30 parent="$1"
  31 single-read
  32 shift
  33
  34 for parent in "$@"; do
  35     # Make it think there are no deletions (pass an empty tree as the source):
  36     single-read -m -i "$(git the-empty-tree)"
  37     shift
  38 done
  39
  40 # The commit message is read from stdin.
  41 GIT_COMMITTER_DATE="$time" \
  42 GIT_AUTHOR_DATE="$time" \
  43 git commit-tree "$(git write-tree)" "${parent_opts[@]}" \
  44     | xargs git tag "$TAG"