git-commit-vandalism/git-merge.sh
Junio C Hamano 720d150c48 Add a new merge strategy by Fredrik Kuivinen.
I really wanted to try this out, instead of asking for an adjustment
to the 'git merge' driver and waiting.  For now the new strategy is
called 'fredrik' and not in the list of default strategies to be tried.

The script wants Python 2.4 so this commit also adjusts Debian and RPM
build procecure files.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-09-10 19:46:53 -07:00

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#!/bin/sh
#
# Copyright (c) 2005 Junio C Hamano
#
. git-sh-setup || die "Not a git archive"
LF='
'
usage () {
die "git-merge [-n] [-s <strategy>]... <merge-message> <head> <remote>+"
}
# all_strategies='resolve fredrik stupid octopus'
all_strategies='fredrik octopus resolve stupid'
default_strategies='resolve octopus'
use_strategies=
dropheads() {
rm -f -- "$GIT_DIR/MERGE_HEAD" || exit 1
}
summary() {
case "$no_summary" in
'')
git-diff-tree -p -M $head "$1" |
git-apply --stat --summary
;;
esac
}
while case "$#" in 0) break ;; esac
do
case "$1" in
-n|--n|--no|--no-|--no-s|--no-su|--no-sum|--no-summ|\
--no-summa|--no-summar|--no-summary)
no_summary=t ;;
-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
--strateg=*|--strategy=*|\
-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
case "$#,$1" in
*,*=*)
strategy=`expr "$1" : '-[^=]*=\(.*\)'` ;;
0,*)
usage ;;
*)
strategy="$2"
shift ;;
esac
case " $all_strategies " in
*" $strategy "*)
use_strategies="$use_strategies$strategy " ;;
*)
die "available strategies are: $all_strategies" ;;
esac
;;
-*) usage ;;
*) break ;;
esac
shift
done
case "$use_strategies" in
'')
use_strategies=$default_strategies
;;
esac
test "$#" -le 2 && usage ;# we need at least two heads.
merge_msg="$1"
shift
head=$(git-rev-parse --verify "$1"^0) || usage
shift
# All the rest are remote heads
for remote
do
git-rev-parse --verify "$remote"^0 >/dev/null ||
die "$remote - not something we can merge"
done
common=$(git-show-branch --merge-base $head "$@")
echo "$head" >"$GIT_DIR/ORIG_HEAD"
case "$#,$common" in
*,'')
die "Unable to find common commit between $head and $*"
;;
1,"$1")
# If head can reach all the merge then we are up to date.
# but first the most common case of merging one remote
echo "Already up-to-date. Yeeah!"
dropheads
exit 0
;;
1,"$head")
# Again the most common case of merging one remote.
echo "Updating from $head to $1."
git-update-index --refresh 2>/dev/null
git-read-tree -u -m $head "$1" || exit 1
git-rev-parse --verify "$1^0" > "$GIT_DIR/HEAD"
summary "$1"
dropheads
exit 0
;;
1,*)
# We are not doing octopus and not fast forward. Need a
# real merge.
;;
*)
# An octopus. If we can reach all the remote we are up to date.
up_to_date=t
for remote
do
common_one=$(git-merge-base $head $remote)
if test "$common_one" != "$remote"
then
up_to_date=f
break
fi
done
if test "$up_to_date" = t
then
echo "Already up-to-date. Yeeah!"
dropheads
exit 0
fi
;;
esac
# At this point we need a real merge. Require that the tree matches
# exactly our head.
git-update-index --refresh &&
test '' = "`git-diff-index --cached --name-only $head`" || {
die "Need real merge but the working tree has local changes."
}
result_tree= best_cnt=-1 best_strategy= wt_strategy=
for strategy in $use_strategies
do
test "$wt_strategy" = '' || {
echo "Rewinding the tree to pristine..."
git reset --hard $head
}
echo "Trying merge strategy $strategy..."
wt_strategy=$strategy
git-merge-$strategy $common -- $head "$@" || {
# The backend exits with 1 when conflicts are left to be resolved,
# with 2 when it does not handle the given merge at all.
exit=$?
if test "$exit" -eq 1
then
cnt=`{
git-diff-files --name-only
git-ls-files --unmerged
} | wc -l`
if test $best_cnt -le 0 -o $cnt -le $best_cnt
then
best_strategy=$strategy
best_cnt=$cnt
fi
fi
continue
}
# Automerge succeeded.
result_tree=$(git-write-tree) && break
done
# If we have a resulting tree, that means the strategy module
# auto resolved the merge cleanly.
if test '' != "$result_tree"
then
parents="-p $head"
for remote
do
parents="$parents -p $remote"
done
result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree $parents)
echo "Committed merge $result_commit, made by $wt_strategy."
echo $result_commit >"$GIT_DIR/HEAD"
summary $result_commit
dropheads
exit 0
fi
# Pick the result from the best strategy and have the user fix it up.
case "$best_strategy" in
'')
git reset --hard $head
die "No merge strategy handled the merge."
;;
"$wt_strategy")
# We already have its result in the working tree.
;;
*)
echo "Rewinding the tree to pristine..."
git reset --hard $head
echo "Using the $best_strategy to prepare resolving by hand."
git-merge-$best_strategy $common -- $head "$@"
;;
esac
for remote
do
echo $remote
done >"$GIT_DIR/MERGE_HEAD"
die "Automatic merge failed; fix up by hand"