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64da9e604e
This adds the coolest merge strategy ever, "ours". It can take arbitrary number of foreign heads and merge them into the current branch, with the resulting tree always taken from our branch head, hence its name. What this means is that you can declare that the current branch supersedes the development histories of other branches using this merge strategy. Signed-off-by: Junio C Hamano <junkio@cox.net>
284 lines
6.2 KiB
Bash
Executable file
284 lines
6.2 KiB
Bash
Executable file
#!/bin/sh
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#
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# Copyright (c) 2005 Junio C Hamano
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#
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. git-sh-setup || die "Not a git archive"
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LF='
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'
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usage () {
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die "git-merge [-n] [--no-commit] [-s <strategy>]... <merge-message> <head> <remote>+"
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}
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# all_strategies='resolve recursive stupid octopus'
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all_strategies='recursive octopus resolve stupid ours'
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default_strategies='resolve octopus'
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use_strategies=
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dropsave() {
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rm -f -- "$GIT_DIR/MERGE_HEAD" "$GIT_DIR/MERGE_MSG" \
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"$GIT_DIR/MERGE_SAVE" || exit 1
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}
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savestate() {
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# Stash away any local modifications.
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git-diff-index -z --name-only $head |
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cpio -0 -o >"$GIT_DIR/MERGE_SAVE"
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}
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restorestate() {
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if test -f "$GIT_DIR/MERGE_SAVE"
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then
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git reset --hard $head
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cpio -iuv <"$GIT_DIR/MERGE_SAVE"
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git-update-index --refresh >/dev/null
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fi
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}
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finish () {
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test '' = "$2" || echo "$2"
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case "$merge_msg" in
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'')
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echo "No merge message -- not updating HEAD"
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;;
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*)
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git-update-ref HEAD "$1" "$head" || exit 1
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;;
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esac
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case "$no_summary" in
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'')
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git-diff-tree -p -M "$head" "$1" |
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git-apply --stat --summary
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;;
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esac
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}
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while case "$#" in 0) break ;; esac
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do
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case "$1" in
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-n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
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--no-summa|--no-summar|--no-summary)
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no_summary=t ;;
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--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
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no_commit=t ;;
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-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
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--strateg=*|--strategy=*|\
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-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
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case "$#,$1" in
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*,*=*)
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strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
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1,*)
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usage ;;
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*)
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strategy="$2"
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shift ;;
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esac
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case " $all_strategies " in
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*" $strategy "*)
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use_strategies="$use_strategies$strategy " ;;
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*)
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die "available strategies are: $all_strategies" ;;
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esac
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;;
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-*) usage ;;
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*) break ;;
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esac
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shift
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done
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case "$use_strategies" in
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'')
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use_strategies=$default_strategies
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;;
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esac
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test "$#" -le 2 && usage ;# we need at least two heads.
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merge_msg="$1"
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shift
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head_arg="$1"
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head=$(git-rev-parse --verify "$1"^0) || usage
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shift
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# All the rest are remote heads
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for remote
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do
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git-rev-parse --verify "$remote"^0 >/dev/null ||
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die "$remote - not something we can merge"
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done
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common=$(git-show-branch --merge-base $head "$@")
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echo "$head" >"$GIT_DIR/ORIG_HEAD"
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case "$#,$common,$no_commit" in
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*,'',*)
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# No common ancestors found. We need a real merge.
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;;
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1,"$1",*)
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# If head can reach all the merge then we are up to date.
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# but first the most common case of merging one remote
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echo "Already up-to-date."
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dropsave
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exit 0
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;;
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1,"$head",*)
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# Again the most common case of merging one remote.
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echo "Updating from $head to $1."
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git-update-index --refresh 2>/dev/null
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new_head=$(git-rev-parse --verify "$1^0") &&
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git-read-tree -u -m $head "$new_head" &&
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finish "$new_head" "Fast forward"
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dropsave
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exit 0
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;;
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1,?*"$LF"?*,*)
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# We are not doing octopus and not fast forward. Need a
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# real merge.
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;;
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1,*,)
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# We are not doing octopus, not fast forward, and have only
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# one common. See if it is really trivial.
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echo "Trying really trivial in-index merge..."
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git-update-index --refresh 2>/dev/null
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if git-read-tree --trivial -m -u $common $head "$1" &&
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result_tree=$(git-write-tree)
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then
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echo "Wonderful."
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result_commit=$(
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echo "$merge_msg" |
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git-commit-tree $result_tree -p HEAD -p "$1"
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) || exit
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finish "$result_commit" "In-index merge"
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dropsave
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exit 0
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fi
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echo "Nope."
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;;
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*)
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# An octopus. If we can reach all the remote we are up to date.
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up_to_date=t
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for remote
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do
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common_one=$(git-merge-base $head $remote)
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if test "$common_one" != "$remote"
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then
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up_to_date=f
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break
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fi
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done
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if test "$up_to_date" = t
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then
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echo "Already up-to-date. Yeeah!"
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dropsave
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exit 0
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fi
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;;
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esac
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# At this point, we need a real merge. No matter what strategy
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# we use, it would operate on the index, possibly affecting the
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# working tree, and when resolved cleanly, have the desired tree
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# in the index -- this means that the index must be in sync with
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# the $head commit. The strategies are responsible to ensure this.
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case "$use_strategies" in
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?*' '?*)
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# Stash away the local changes so that we can try more than one.
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savestate
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single_strategy=no
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;;
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*)
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rm -f "$GIT_DIR/MERGE_SAVE"
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single_strategy=yes
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;;
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esac
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result_tree= best_cnt=-1 best_strategy= wt_strategy=
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for strategy in $use_strategies
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do
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test "$wt_strategy" = '' || {
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echo "Rewinding the tree to pristine..."
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restorestate
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}
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case "$single_strategy" in
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no)
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echo "Trying merge strategy $strategy..."
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;;
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esac
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# Remember which strategy left the state in the working tree
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wt_strategy=$strategy
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git-merge-$strategy $common -- "$head_arg" "$@"
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exit=$?
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if test "$no_commit" = t && test "$exit" = 0
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then
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exit=1 ;# pretend it left conflicts.
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fi
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test "$exit" = 0 || {
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# The backend exits with 1 when conflicts are left to be resolved,
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# with 2 when it does not handle the given merge at all.
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if test "$exit" -eq 1
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then
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cnt=`{
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git-diff-files --name-only
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git-ls-files --unmerged
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} | wc -l`
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if test $best_cnt -le 0 -o $cnt -le $best_cnt
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then
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best_strategy=$strategy
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best_cnt=$cnt
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fi
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fi
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continue
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}
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# Automerge succeeded.
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result_tree=$(git-write-tree) && break
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done
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# If we have a resulting tree, that means the strategy module
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# auto resolved the merge cleanly.
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if test '' != "$result_tree"
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then
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parents="-p $head"
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for remote
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do
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parents="$parents -p $remote"
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done
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result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents) || exit
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finish "$result_commit" "Merge $result_commit, made by $wt_strategy."
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dropsave
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exit 0
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fi
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# Pick the result from the best strategy and have the user fix it up.
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case "$best_strategy" in
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'')
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restorestate
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die "No merge strategy handled the merge."
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;;
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"$wt_strategy")
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# We already have its result in the working tree.
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;;
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*)
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echo "Rewinding the tree to pristine..."
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restorestate
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echo "Using the $best_strategy to prepare resolving by hand."
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git-merge-$best_strategy $common -- "$head_arg" "$@"
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;;
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esac
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for remote
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do
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echo $remote
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done >"$GIT_DIR/MERGE_HEAD"
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echo $merge_msg >"$GIT_DIR/MERGE_MSG"
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die "Automatic merge failed/prevented; fix up by hand"
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