Merge branch 'uk/maint-1.5.3-rebase-i-reflog' into maint
authorJunio C Hamano <gitster@pobox.com>
Thu, 11 Jun 2009 21:14:00 +0000 (14:14 -0700)
committerJunio C Hamano <gitster@pobox.com>
Thu, 11 Jun 2009 21:14:00 +0000 (14:14 -0700)
* uk/maint-1.5.3-rebase-i-reflog:
rebase--interactive: remote stray closing parenthesis

Conflicts:
git-rebase--interactive.sh

1  2 
git-rebase--interactive.sh
index 314cd364b8f4df5e170dd0ffd9e874b3e6c2737c,70cb2e30b4b7b3f3c3cf5ccef1d63b843bc46944..f96d887d23653019e3387eced2779d50b3f09fa2
  # The original idea comes from Eric W. Biederman, in
  # http://article.gmane.org/gmane.comp.version-control.git/22407
  
 -USAGE='(--continue | --abort | --skip | [--onto <branch>] <upstream> [<branch>])'
 +OPTIONS_KEEPDASHDASH=
 +OPTIONS_SPEC="\
 +git-rebase [-i] [options] [--] <upstream> [<branch>]
 +git-rebase [-i] (--continue | --abort | --skip)
 +--
 + Available options are
 +v,verbose          display a diffstat of what changed upstream
 +onto=              rebase onto given branch instead of upstream
 +p,preserve-merges  try to recreate merges instead of ignoring them
 +s,strategy=        use the given merge strategy
 +m,merge            always used (no-op)
 +i,interactive      always used (no-op)
 + Actions:
 +continue           continue rebasing process
 +abort              abort rebasing process and restore original branch
 +skip               skip current patch and continue rebasing process
 +no-verify          override pre-rebase hook from stopping the operation
 +root               rebase all reachable commmits up to the root(s)
 +"
  
  . git-sh-setup
  require_work_tree
  
 -DOTEST="$GIT_DIR/.dotest-merge"
 -TODO="$DOTEST"/todo
 +DOTEST="$GIT_DIR/rebase-merge"
 +TODO="$DOTEST"/git-rebase-todo
  DONE="$DOTEST"/done
 +MSG="$DOTEST"/message
 +SQUASH_MSG="$DOTEST"/message-squash
 +REWRITTEN="$DOTEST"/rewritten
 +DROPPED="$DOTEST"/dropped
 +PRESERVE_MERGES=
  STRATEGY=
 +ONTO=
  VERBOSE=
 +OK_TO_SKIP_PRE_REBASE=
 +REBASE_ROOT=
 +
 +GIT_CHERRY_PICK_HELP="  After resolving the conflicts,
 +mark the corrected paths with 'git add <paths>', and
 +run 'git rebase --continue'"
 +export GIT_CHERRY_PICK_HELP
  
  warn () {
        echo "$*" >&2
  }
  
 +output () {
 +      case "$VERBOSE" in
 +      '')
 +              output=$("$@" 2>&1 )
 +              status=$?
 +              test $status != 0 && printf "%s\n" "$output"
 +              return $status
 +              ;;
 +      *)
 +              "$@"
 +              ;;
 +      esac
 +}
 +
 +run_pre_rebase_hook () {
 +      if test -z "$OK_TO_SKIP_PRE_REBASE" &&
 +         test -x "$GIT_DIR/hooks/pre-rebase"
 +      then
 +              "$GIT_DIR/hooks/pre-rebase" ${1+"$@"} || {
 +                      echo >&2 "The pre-rebase hook refused to rebase."
 +                      exit 1
 +              }
 +      fi
 +}
 +
  require_clean_work_tree () {
        # test if working tree is dirty
        git rev-parse --verify HEAD > /dev/null &&
 -      git update-index --refresh &&
 -      git diff-files --quiet &&
 -      git diff-index --cached --quiet HEAD ||
 +      git update-index --ignore-submodules --refresh &&
 +      git diff-files --quiet --ignore-submodules &&
 +      git diff-index --cached --quiet HEAD --ignore-submodules -- ||
        die "Working tree is dirty"
  }
  
@@@ -97,47 -41,22 +97,47 @@@ comment_for_reflog () 
        ''|rebase*)
                GIT_REFLOG_ACTION="rebase -i ($1)"
                export GIT_REFLOG_ACTION
 +              ;;
        esac
  }
  
 +last_count=
  mark_action_done () {
        sed -e 1q < "$TODO" >> "$DONE"
        sed -e 1d < "$TODO" >> "$TODO".new
        mv -f "$TODO".new "$TODO"
 +      count=$(grep -c '^[^#]' < "$DONE")
 +      total=$(($count+$(grep -c '^[^#]' < "$TODO")))
 +      if test "$last_count" != "$count"
 +      then
 +              last_count=$count
 +              printf "Rebasing (%d/%d)\r" $count $total
 +              test -z "$VERBOSE" || echo
 +      fi
  }
  
  make_patch () {
 -      parent_sha1=$(git rev-parse --verify "$1"^ 2> /dev/null)
 -      git diff "$parent_sha1".."$1" > "$DOTEST"/patch
 +      sha1_and_parents="$(git rev-list --parents -1 "$1")"
 +      case "$sha1_and_parents" in
 +      ?*' '?*' '?*)
 +              git diff --cc $sha1_and_parents
 +              ;;
 +      ?*' '?*)
 +              git diff-tree -p "$1^!"
 +              ;;
 +      *)
 +              echo "Root commit"
 +              ;;
 +      esac > "$DOTEST"/patch
 +      test -f "$DOTEST"/message ||
 +              git cat-file commit "$1" | sed "1,/^$/d" > "$DOTEST"/message
 +      test -f "$DOTEST"/author-script ||
 +              get_author_ident_from_commit "$1" > "$DOTEST"/author-script
  }
  
  die_with_patch () {
        make_patch "$1"
 +      git rerere
        die "$2"
  }
  
@@@ -146,270 -65,89 +146,270 @@@ die_abort () 
        die "$1"
  }
  
 +has_action () {
 +      grep '^[^#]' "$1" >/dev/null
 +}
 +
  pick_one () {
 -      case "$1" in -n) sha1=$2 ;; *) sha1=$1 ;; esac
 -      git rev-parse --verify $sha1 || die "Invalid commit name: $sha1"
 -      parent_sha1=$(git rev-parse --verify $sha1^ 2>/dev/null)
 +      no_ff=
 +      case "$1" in -n) sha1=$2; no_ff=t ;; *) sha1=$1 ;; esac
 +      output git rev-parse --verify $sha1 || die "Invalid commit name: $sha1"
 +      test -d "$REWRITTEN" &&
 +              pick_one_preserving_merges "$@" && return
 +      if test ! -z "$REBASE_ROOT"
 +      then
 +              output git cherry-pick "$@"
 +              return
 +      fi
 +      parent_sha1=$(git rev-parse --verify $sha1^) ||
 +              die "Could not get the parent of $sha1"
        current_sha1=$(git rev-parse --verify HEAD)
 -      if [ $current_sha1 = $parent_sha1 ]; then
 -              git reset --hard $sha1
 +      if test "$no_ff$current_sha1" = "$parent_sha1"; then
 +              output git reset --hard $sha1
 +              test "a$1" = a-n && output git reset --soft $current_sha1
                sha1=$(git rev-parse --short $sha1)
 -              warn Fast forward to $sha1
 +              output warn Fast forward to $sha1
 +      else
 +              output git cherry-pick "$@"
 +      fi
 +}
 +
 +pick_one_preserving_merges () {
 +      fast_forward=t
 +      case "$1" in
 +      -n)
 +              fast_forward=f
 +              sha1=$2
 +              ;;
 +      *)
 +              sha1=$1
 +              ;;
 +      esac
 +      sha1=$(git rev-parse $sha1)
 +
 +      if test -f "$DOTEST"/current-commit
 +      then
 +              if test "$fast_forward" = t
 +              then
 +                      cat "$DOTEST"/current-commit | while read current_commit
 +                      do
 +                              git rev-parse HEAD > "$REWRITTEN"/$current_commit
 +                      done
 +                      rm "$DOTEST"/current-commit ||
 +                      die "Cannot write current commit's replacement sha1"
 +              fi
 +      fi
 +
 +      echo $sha1 >> "$DOTEST"/current-commit
 +
 +      # rewrite parents; if none were rewritten, we can fast-forward.
 +      new_parents=
 +      pend=" $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)"
 +      if test "$pend" = " "
 +      then
 +              pend=" root"
 +      fi
 +      while [ "$pend" != "" ]
 +      do
 +              p=$(expr "$pend" : ' \([^ ]*\)')
 +              pend="${pend# $p}"
 +
 +              if test -f "$REWRITTEN"/$p
 +              then
 +                      new_p=$(cat "$REWRITTEN"/$p)
 +
 +                      # If the todo reordered commits, and our parent is marked for
 +                      # rewriting, but hasn't been gotten to yet, assume the user meant to
 +                      # drop it on top of the current HEAD
 +                      if test -z "$new_p"
 +                      then
 +                              new_p=$(git rev-parse HEAD)
 +                      fi
 +
 +                      test $p != $new_p && fast_forward=f
 +                      case "$new_parents" in
 +                      *$new_p*)
 +                              ;; # do nothing; that parent is already there
 +                      *)
 +                              new_parents="$new_parents $new_p"
 +                              ;;
 +                      esac
 +              else
 +                      if test -f "$DROPPED"/$p
 +                      then
 +                              fast_forward=f
 +                              replacement="$(cat "$DROPPED"/$p)"
 +                              test -z "$replacement" && replacement=root
 +                              pend=" $replacement$pend"
 +                      else
 +                              new_parents="$new_parents $p"
 +                      fi
 +              fi
 +      done
 +      case $fast_forward in
 +      t)
 +              output warn "Fast forward to $sha1"
 +              output git reset --hard $sha1 ||
 +                      die "Cannot fast forward to $sha1"
 +              ;;
 +      f)
 +              first_parent=$(expr "$new_parents" : ' \([^ ]*\)')
 +
 +              if [ "$1" != "-n" ]
 +              then
 +                      # detach HEAD to current parent
 +                      output git checkout $first_parent 2> /dev/null ||
 +                              die "Cannot move HEAD to $first_parent"
 +              fi
 +
 +              case "$new_parents" in
 +              ' '*' '*)
 +                      test "a$1" = a-n && die "Refusing to squash a merge: $sha1"
 +
 +                      # redo merge
 +                      author_script=$(get_author_ident_from_commit $sha1)
 +                      eval "$author_script"
 +                      msg="$(git cat-file commit $sha1 | sed -e '1,/^$/d')"
 +                      # No point in merging the first parent, that's HEAD
 +                      new_parents=${new_parents# $first_parent}
 +                      if ! GIT_AUTHOR_NAME="$GIT_AUTHOR_NAME" \
 +                              GIT_AUTHOR_EMAIL="$GIT_AUTHOR_EMAIL" \
 +                              GIT_AUTHOR_DATE="$GIT_AUTHOR_DATE" \
 +                              output git merge $STRATEGY -m "$msg" \
 +                                      $new_parents
 +                      then
 +                              printf "%s\n" "$msg" > "$GIT_DIR"/MERGE_MSG
 +                              die_with_patch $sha1 "Error redoing merge $sha1"
 +                      fi
 +                      ;;
 +              *)
 +                      output git cherry-pick "$@" ||
 +                              die_with_patch $sha1 "Could not pick $sha1"
 +                      ;;
 +              esac
 +              ;;
 +      esac
 +}
 +
 +nth_string () {
 +      case "$1" in
 +      *1[0-9]|*[04-9]) echo "$1"th;;
 +      *1) echo "$1"st;;
 +      *2) echo "$1"nd;;
 +      *3) echo "$1"rd;;
 +      esac
 +}
 +
 +make_squash_message () {
 +      if test -f "$SQUASH_MSG"; then
 +              COUNT=$(($(sed -n "s/^# This is [^0-9]*\([1-9][0-9]*\).*/\1/p" \
 +                      < "$SQUASH_MSG" | sed -ne '$p')+1))
 +              echo "# This is a combination of $COUNT commits."
 +              sed -e 1d -e '2,/^./{
 +                      /^$/d
 +              }' <"$SQUASH_MSG"
        else
 -              git cherry-pick $STRATEGY "$@"
 +              COUNT=2
 +              echo "# This is a combination of two commits."
 +              echo "# The first commit's message is:"
 +              echo
 +              git cat-file commit HEAD | sed -e '1,/^$/d'
        fi
 +      echo
 +      echo "# This is the $(nth_string $COUNT) commit message:"
 +      echo
 +      git cat-file commit $1 | sed -e '1,/^$/d'
 +}
 +
 +peek_next_command () {
 +      sed -n "1s/ .*$//p" < "$TODO"
  }
  
  do_next () {
 +      rm -f "$DOTEST"/message "$DOTEST"/author-script \
 +              "$DOTEST"/amend || exit
        read command sha1 rest < "$TODO"
        case "$command" in
 -      \#|'')
 +      '#'*|''|noop)
                mark_action_done
 -              continue
                ;;
 -      pick)
 +      pick|p)
                comment_for_reflog pick
  
                mark_action_done
                pick_one $sha1 ||
                        die_with_patch $sha1 "Could not apply $sha1... $rest"
                ;;
 -      edit)
 +      edit|e)
                comment_for_reflog edit
  
                mark_action_done
                pick_one $sha1 ||
                        die_with_patch $sha1 "Could not apply $sha1... $rest"
                make_patch $sha1
 -              warn
 +              git rev-parse --verify HEAD > "$DOTEST"/amend
 +              warn "Stopped at $sha1... $rest"
                warn "You can amend the commit now, with"
                warn
                warn "  git commit --amend"
                warn
 +              warn "Once you are satisfied with your changes, run"
 +              warn
 +              warn "  git rebase --continue"
 +              warn
                exit 0
                ;;
 -      squash)
 +      squash|s)
                comment_for_reflog squash
  
 -              test -z "$(grep -ve '^$' -e '^#' < $DONE)" &&
 +              test -f "$DONE" && has_action "$DONE" ||
                        die "Cannot 'squash' without a previous commit"
  
                mark_action_done
 +              make_squash_message $sha1 > "$MSG"
                failed=f
 +              author_script=$(get_author_ident_from_commit HEAD)
 +              output git reset --soft HEAD^
                pick_one -n $sha1 || failed=t
 -              MSG="$DOTEST"/message
 -              echo "# This is a combination of two commits." > "$MSG"
 -              echo "# The first commit's message is:" >> "$MSG"
 -              echo >> "$MSG"
 -              git cat-file commit HEAD | sed -e '1,/^$/d' >> "$MSG"
 -              echo >> "$MSG"
 -              echo "# And this is the 2nd commit message:" >> "$MSG"
 -              echo >> "$MSG"
 -              git cat-file commit $sha1 | sed -e '1,/^$/d' >> "$MSG"
 -              git reset --soft HEAD^
 -              author_script=$(get_author_ident_from_commit $sha1)
 -              case $failed in
 -              f)
 +              case "$(peek_next_command)" in
 +              squash|s)
 +                      USE_OUTPUT=output
 +                      MSG_OPT=-F
 +                      EDIT_OR_FILE="$MSG"
 +                      cp "$MSG" "$SQUASH_MSG"
 +                      ;;
 +              *)
 +                      USE_OUTPUT=
 +                      MSG_OPT=
 +                      EDIT_OR_FILE=-e
 +                      rm -f "$SQUASH_MSG" || exit
 +                      cp "$MSG" "$GIT_DIR"/SQUASH_MSG
 +                      rm -f "$GIT_DIR"/MERGE_MSG || exit
 +                      ;;
 +              esac
 +              echo "$author_script" > "$DOTEST"/author-script
 +              if test $failed = f
 +              then
                        # This is like --amend, but with a different message
                        eval "$author_script"
 -                      export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE
 -                      git commit -F "$MSG" -e
 -                      ;;
 -              t)
 +                      GIT_AUTHOR_NAME="$GIT_AUTHOR_NAME" \
 +                      GIT_AUTHOR_EMAIL="$GIT_AUTHOR_EMAIL" \
 +                      GIT_AUTHOR_DATE="$GIT_AUTHOR_DATE" \
 +                      $USE_OUTPUT git commit --no-verify \
 +                              $MSG_OPT "$EDIT_OR_FILE" || failed=t
 +              fi
 +              if test $failed = t
 +              then
                        cp "$MSG" "$GIT_DIR"/MERGE_MSG
                        warn
                        warn "Could not apply $sha1... $rest"
 -                      warn "After you fixed that, commit the result with"
 -                      warn
 -                      warn "  $(echo $author_script | tr '\012' ' ') \\"
 -                      warn "    git commit -F \"$GIT_DIR\"/MERGE_MSG -e"
                        die_with_patch $sha1 ""
 -              esac
 +              fi
                ;;
        *)
                warn "Unknown command: $command $sha1 $rest"
                die_with_patch $sha1 "Please fix this in the file $TODO."
 +              ;;
        esac
        test -s "$TODO" && return
  
        OLDHEAD=$(cat "$DOTEST"/head) &&
        SHORTONTO=$(git rev-parse --short $(cat "$DOTEST"/onto)) &&
        NEWHEAD=$(git rev-parse HEAD) &&
 -      message="$GIT_REFLOG_ACTION: $HEADNAME onto $SHORTONTO" &&
 -      git update-ref -m "$message" $HEADNAME $NEWHEAD $OLDHEAD &&
 -      git symbolic-ref HEAD $HEADNAME &&
 +      case $HEADNAME in
 +      refs/*)
-               message="$GIT_REFLOG_ACTION: $HEADNAME onto $SHORTONTO)" &&
++              message="$GIT_REFLOG_ACTION: $HEADNAME onto $SHORTONTO" &&
 +              git update-ref -m "$message" $HEADNAME $NEWHEAD $OLDHEAD &&
 +              git symbolic-ref HEAD $HEADNAME
 +              ;;
 +      esac && {
 +              test ! -f "$DOTEST"/verbose ||
 +                      git diff-tree --stat $(cat "$DOTEST"/head)..HEAD
 +      } &&
        rm -rf "$DOTEST" &&
 +      git gc --auto &&
        warn "Successfully rebased and updated $HEADNAME."
  
        exit
@@@ -440,131 -170,46 +440,131 @@@ do_rest () 
        do
                do_next
        done
 -      test -f "$DOTEST"/verbose &&
 -              git diff --stat $(cat "$DOTEST"/head)..HEAD
 -      exit
  }
  
 -while case $# in 0) break ;; esac
 +# skip picking commits whose parents are unchanged
 +skip_unnecessary_picks () {
 +      fd=3
 +      while read command sha1 rest
 +      do
 +              # fd=3 means we skip the command
 +              case "$fd,$command,$(git rev-parse --verify --quiet $sha1^)" in
 +              3,pick,"$ONTO"*|3,p,"$ONTO"*)
 +                      # pick a commit whose parent is current $ONTO -> skip
 +                      ONTO=$sha1
 +                      ;;
 +              3,#*|3,,*)
 +                      # copy comments
 +                      ;;
 +              *)
 +                      fd=1
 +                      ;;
 +              esac
 +              echo "$command${sha1:+ }$sha1${rest:+ }$rest" >&$fd
 +      done <"$TODO" >"$TODO.new" 3>>"$DONE" &&
 +      mv -f "$TODO".new "$TODO" ||
 +      die "Could not skip unnecessary pick commands"
 +}
 +
 +# check if no other options are set
 +is_standalone () {
 +      test $# -eq 2 -a "$2" = '--' &&
 +      test -z "$ONTO" &&
 +      test -z "$PRESERVE_MERGES" &&
 +      test -z "$STRATEGY" &&
 +      test -z "$VERBOSE"
 +}
 +
 +get_saved_options () {
 +      test -d "$REWRITTEN" && PRESERVE_MERGES=t
 +      test -f "$DOTEST"/strategy && STRATEGY="$(cat "$DOTEST"/strategy)"
 +      test -f "$DOTEST"/verbose && VERBOSE=t
 +      test -f "$DOTEST"/rebase-root && REBASE_ROOT=t
 +}
 +
 +while test $# != 0
  do
        case "$1" in
 +      --no-verify)
 +              OK_TO_SKIP_PRE_REBASE=yes
 +              ;;
 +      --verify)
 +              ;;
        --continue)
 +              is_standalone "$@" || usage
 +              get_saved_options
                comment_for_reflog continue
  
                test -d "$DOTEST" || die "No interactive rebase running"
  
 +              # Sanity check
 +              git rev-parse --verify HEAD >/dev/null ||
 +                      die "Cannot read HEAD"
 +              git update-index --ignore-submodules --refresh &&
 +                      git diff-files --quiet --ignore-submodules ||
 +                      die "Working tree is dirty"
 +
 +              # do we have anything to commit?
 +              if git diff-index --cached --quiet --ignore-submodules HEAD --
 +              then
 +                      : Nothing to commit -- skip this
 +              else
 +                      . "$DOTEST"/author-script ||
 +                              die "Cannot find the author identity"
 +                      amend=
 +                      if test -f "$DOTEST"/amend
 +                      then
 +                              amend=$(git rev-parse --verify HEAD)
 +                              test "$amend" = $(cat "$DOTEST"/amend) ||
 +                              die "\
 +You have uncommitted changes in your working tree. Please, commit them
 +first and then run 'git rebase --continue' again."
 +                              git reset --soft HEAD^ ||
 +                              die "Cannot rewind the HEAD"
 +                      fi
 +                      export GIT_AUTHOR_NAME GIT_AUTHOR_EMAIL GIT_AUTHOR_DATE &&
 +                      git commit --no-verify -F "$DOTEST"/message -e || {
 +                              test -n "$amend" && git reset --soft $amend
 +                              die "Could not commit staged changes."
 +                      }
 +              fi
 +
                require_clean_work_tree
                do_rest
                ;;
        --abort)
 +              is_standalone "$@" || usage
 +              get_saved_options
                comment_for_reflog abort
  
 +              git rerere clear
                test -d "$DOTEST" || die "No interactive rebase running"
  
                HEADNAME=$(cat "$DOTEST"/head-name)
                HEAD=$(cat "$DOTEST"/head)
 -              git symbolic-ref HEAD $HEADNAME &&
 -              git reset --hard $HEAD &&
 +              case $HEADNAME in
 +              refs/*)
 +                      git symbolic-ref HEAD $HEADNAME
 +                      ;;
 +              esac &&
 +              output git reset --hard $HEAD &&
                rm -rf "$DOTEST"
                exit
                ;;
        --skip)
 +              is_standalone "$@" || usage
 +              get_saved_options
                comment_for_reflog skip
  
 +              git rerere clear
                test -d "$DOTEST" || die "No interactive rebase running"
  
 -              git reset --hard && do_rest
 +              output git reset --hard && do_rest
                ;;
 -      -s|--strategy)
 -              shift
 +      -s)
                case "$#,$1" in
                *,*=*)
 -                      STRATEGY="-s `expr "z$1" : 'z-[^=]*=\(.*\)'`" ;;
 +                      STRATEGY="-s "$(expr "z$1" : 'z-[^=]*=\(.*\)') ;;
                1,*)
                        usage ;;
                *)
                        shift ;;
                esac
                ;;
 -      --merge)
 +      -m)
                # we use merge anyway
                ;;
 -      -C*)
 -              die "Interactive rebase uses merge, so $1 does not make sense"
 -              ;;
 -      -v|--verbose)
 +      -v)
                VERBOSE=t
                ;;
 -      -i|--interactive)
 +      -p)
 +              PRESERVE_MERGES=t
 +              ;;
 +      -i)
                # yeah, we know
                ;;
 -      ''|-h)
 -              usage
 +      --root)
 +              REBASE_ROOT=t
                ;;
 -      *)
 +      --onto)
 +              shift
 +              ONTO=$(git rev-parse --verify "$1") ||
 +                      die "Does not point to a valid commit: $1"
 +              ;;
 +      --)
 +              shift
 +              test -z "$REBASE_ROOT" -a $# -ge 1 -a $# -le 2 ||
 +              test ! -z "$REBASE_ROOT" -a $# -le 1 || usage
                test -d "$DOTEST" &&
                        die "Interactive rebase already started"
  
                git var GIT_COMMITTER_IDENT >/dev/null ||
                        die "You need to set your committer info first"
  
 -              comment_for_reflog start
 +              if test -z "$REBASE_ROOT"
 +              then
 +                      UPSTREAM_ARG="$1"
 +                      UPSTREAM=$(git rev-parse --verify "$1") || die "Invalid base"
 +                      test -z "$ONTO" && ONTO=$UPSTREAM
 +                      shift
 +              else
 +                      UPSTREAM=
 +                      UPSTREAM_ARG=--root
 +                      test -z "$ONTO" &&
 +                              die "You must specify --onto when using --root"
 +              fi
 +              run_pre_rebase_hook "$UPSTREAM_ARG" "$@"
  
 -              ONTO=
 -              case "$1" in
 -              --onto)
 -                      ONTO=$(git rev-parse --verify "$2") ||
 -                              die "Does not point to a valid commit: $2"
 -                      shift; shift
 -                      ;;
 -              esac
 +              comment_for_reflog start
  
                require_clean_work_tree
  
 -              if [ ! -z "$2"]
 +              if test ! -z "$1"
                then
 -                      git show-ref --verify --quiet "refs/heads/$2" ||
 -                              die "Invalid branchname: $2"
 -                      git checkout "$2" ||
 -                              die "Could not checkout $2"
 +                      output git show-ref --verify --quiet "refs/heads/$1" ||
 +                              die "Invalid branchname: $1"
 +                      output git checkout "$1" ||
 +                              die "Could not checkout $1"
                fi
  
                HEAD=$(git rev-parse --verify HEAD) || die "No HEAD?"
 -              UPSTREAM=$(git rev-parse --verify "$1") || die "Invalid base"
 -
 -              test -z "$ONTO" && ONTO=$UPSTREAM
 -
                mkdir "$DOTEST" || die "Could not create temporary $DOTEST"
 +
                : > "$DOTEST"/interactive || die "Could not mark as interactive"
 -              git symbolic-ref HEAD > "$DOTEST"/head-name ||
 -                      die "Could not get HEAD"
 +              git symbolic-ref HEAD > "$DOTEST"/head-name 2> /dev/null ||
 +                      echo "detached HEAD" > "$DOTEST"/head-name
  
                echo $HEAD > "$DOTEST"/head
 -              echo $UPSTREAM > "$DOTEST"/upstream
 +              case "$REBASE_ROOT" in
 +              '')
 +                      rm -f "$DOTEST"/rebase-root ;;
 +              *)
 +                      : >"$DOTEST"/rebase-root ;;
 +              esac
                echo $ONTO > "$DOTEST"/onto
 +              test -z "$STRATEGY" || echo "$STRATEGY" > "$DOTEST"/strategy
                test t = "$VERBOSE" && : > "$DOTEST"/verbose
 +              if test t = "$PRESERVE_MERGES"
 +              then
 +                      # $REWRITTEN contains files for each commit that is
 +                      # reachable by at least one merge base of $HEAD and
 +                      # $UPSTREAM. They are not necessarily rewritten, but
 +                      # their children might be.
 +                      # This ensures that commits on merged, but otherwise
 +                      # unrelated side branches are left alone. (Think "X"
 +                      # in the man page's example.)
 +                      if test -z "$REBASE_ROOT"
 +                      then
 +                              mkdir "$REWRITTEN" &&
 +                              for c in $(git merge-base --all $HEAD $UPSTREAM)
 +                              do
 +                                      echo $ONTO > "$REWRITTEN"/$c ||
 +                                              die "Could not init rewritten commits"
 +                              done
 +                      else
 +                              mkdir "$REWRITTEN" &&
 +                              echo $ONTO > "$REWRITTEN"/root ||
 +                                      die "Could not init rewritten commits"
 +                      fi
 +                      # No cherry-pick because our first pass is to determine
 +                      # parents to rewrite and skipping dropped commits would
 +                      # prematurely end our probe
 +                      MERGES_OPTION=
 +                      first_after_upstream="$(git rev-list --reverse --first-parent $UPSTREAM..$HEAD | head -n 1)"
 +              else
 +                      MERGES_OPTION="--no-merges --cherry-pick"
 +              fi
  
 -              SHORTUPSTREAM=$(git rev-parse --short $UPSTREAM)
                SHORTHEAD=$(git rev-parse --short $HEAD)
                SHORTONTO=$(git rev-parse --short $ONTO)
 -              cat > "$TODO" << EOF
 -# Rebasing $SHORTUPSTREAM..$SHORTHEAD onto $SHORTONTO
 +              if test -z "$REBASE_ROOT"
 +                      # this is now equivalent to ! -z "$UPSTREAM"
 +              then
 +                      SHORTUPSTREAM=$(git rev-parse --short $UPSTREAM)
 +                      REVISIONS=$UPSTREAM...$HEAD
 +                      SHORTREVISIONS=$SHORTUPSTREAM..$SHORTHEAD
 +              else
 +                      REVISIONS=$ONTO...$HEAD
 +                      SHORTREVISIONS=$SHORTHEAD
 +              fi
 +              git rev-list $MERGES_OPTION --pretty=oneline --abbrev-commit \
 +                      --abbrev=7 --reverse --left-right --topo-order \
 +                      $REVISIONS | \
 +                      sed -n "s/^>//p" | while read shortsha1 rest
 +              do
 +                      if test t != "$PRESERVE_MERGES"
 +                      then
 +                              echo "pick $shortsha1 $rest" >> "$TODO"
 +                      else
 +                              sha1=$(git rev-parse $shortsha1)
 +                              if test -z "$REBASE_ROOT"
 +                              then
 +                                      preserve=t
 +                                      for p in $(git rev-list --parents -1 $sha1 | cut -d' ' -s -f2-)
 +                                      do
 +                                              if test -f "$REWRITTEN"/$p -a \( $p != $UPSTREAM -o $sha1 = $first_after_upstream \)
 +                                              then
 +                                                      preserve=f
 +                                              fi
 +                                      done
 +                              else
 +                                      preserve=f
 +                              fi
 +                              if test f = "$preserve"
 +                              then
 +                                      touch "$REWRITTEN"/$sha1
 +                                      echo "pick $shortsha1 $rest" >> "$TODO"
 +                              fi
 +                      fi
 +              done
 +
 +              # Watch for commits that been dropped by --cherry-pick
 +              if test t = "$PRESERVE_MERGES"
 +              then
 +                      mkdir "$DROPPED"
 +                      # Save all non-cherry-picked changes
 +                      git rev-list $REVISIONS --left-right --cherry-pick | \
 +                              sed -n "s/^>//p" > "$DOTEST"/not-cherry-picks
 +                      # Now all commits and note which ones are missing in
 +                      # not-cherry-picks and hence being dropped
 +                      git rev-list $REVISIONS |
 +                      while read rev
 +                      do
 +                              if test -f "$REWRITTEN"/$rev -a "$(grep "$rev" "$DOTEST"/not-cherry-picks)" = ""
 +                              then
 +                                      # Use -f2 because if rev-list is telling us this commit is
 +                                      # not worthwhile, we don't want to track its multiple heads,
 +                                      # just the history of its first-parent for others that will
 +                                      # be rebasing on top of it
 +                                      git rev-list --parents -1 $rev | cut -d' ' -s -f2 > "$DROPPED"/$rev
 +                                      short=$(git rev-list -1 --abbrev-commit --abbrev=7 $rev)
 +                                      grep -v "^[a-z][a-z]* $short" <"$TODO" > "${TODO}2" ; mv "${TODO}2" "$TODO"
 +                                      rm "$REWRITTEN"/$rev
 +                              fi
 +                      done
 +              fi
 +
 +              test -s "$TODO" || echo noop >> "$TODO"
 +              cat >> "$TODO" << EOF
 +
 +# Rebase $SHORTREVISIONS onto $SHORTONTO
  #
  # Commands:
 -#  pick = use commit
 -#  edit = use commit, but stop for amending
 -#  squash = use commit, but meld into previous commit
 +#  p, pick = use commit
 +#  e, edit = use commit, but stop for amending
 +#  s, squash = use commit, but meld into previous commit
 +#
 +# If you remove a line here THAT COMMIT WILL BE LOST.
 +# However, if you remove everything, the rebase will be aborted.
 +#
  EOF
 -              git rev-list --no-merges --pretty=oneline --abbrev-commit \
 -                      --abbrev=7 --reverse $UPSTREAM..$HEAD | \
 -                      sed "s/^/pick /" >> "$TODO"
  
 -              test -z "$(grep -ve '^$' -e '^#' < $TODO)" &&
 +              has_action "$TODO" ||
                        die_abort "Nothing to do"
  
                cp "$TODO" "$TODO".backup
 -              ${VISUAL:-${EDITOR:-vi}} "$TODO" ||
 +              git_editor "$TODO" ||
                        die "Could not execute editor"
  
 -              test -z "$(grep -ve '^$' -e '^#' < $TODO)" &&
 +              has_action "$TODO" ||
                        die_abort "Nothing to do"
  
 -              git checkout $ONTO && do_rest
 +              test -d "$REWRITTEN" || skip_unnecessary_picks
 +
 +              git update-ref ORIG_HEAD $HEAD
 +              output git checkout $ONTO && do_rest
 +              ;;
        esac
        shift
  done