git/git-merge-octopus.sh
Junio C Hamano d165fa14f0 define die() for scripts that use it.
As a fallout from not using git-sh-setup in scripts that can
operate from a subdirectory, we lost definition of die() from
them.  It might make sense to do some cleanup to consolidate
them back again, but this should suffice for now.

Signed-off-by: Junio C Hamano <junkio@cox.net>
2005-11-28 23:13:03 -08:00

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#!/bin/sh
#
# Copyright (c) 2005 Junio C Hamano
#
# Resolve two or more trees.
#
LF='
'
die () {
echo >&2 "$*"
exit 1
}
# The first parameters up to -- are merge bases; the rest are heads.
bases= head= remotes= sep_seen=
for arg
do
case ",$sep_seen,$head,$arg," in
*,--,)
sep_seen=yes
;;
,yes,,*)
head=$arg
;;
,yes,*)
remotes="$remotes$arg "
;;
*)
bases="$bases$arg "
;;
esac
done
# Reject if this is not an Octopus -- resolve should be used instead.
case "$remotes" in
?*' '?*)
;;
*)
exit 2 ;;
esac
# MRC is the current "merge reference commit"
# MRT is the current "merge result tree"
MRC=$head MSG= PARENT="-p $head"
MRT=$(git-write-tree)
CNT=1 ;# counting our head
NON_FF_MERGE=0
for SHA1 in $remotes
do
common=$(git-merge-base --all $MRC $SHA1) ||
die "Unable to find common commit with $SHA1"
case "$common" in
?*"$LF"?*)
die "Not trivially mergeable."
;;
$SHA1)
echo "Already up-to-date with $SHA1"
continue
;;
esac
CNT=`expr $CNT + 1`
PARENT="$PARENT -p $SHA1"
if test "$common,$NON_FF_MERGE" = "$MRC,0"
then
# The first head being merged was a fast-forward.
# Advance MRC to the head being merged, and use that
# tree as the intermediate result of the merge.
# We still need to count this as part of the parent set.
echo "Fast forwarding to: $SHA1"
git-read-tree -u -m $head $SHA1 || exit
MRC=$SHA1 MRT=$(git-write-tree)
continue
fi
NON_FF_MERGE=1
echo "Trying simple merge with $SHA1"
git-read-tree -u -m $common $MRT $SHA1 || exit 2
next=$(git-write-tree 2>/dev/null)
if test $? -ne 0
then
echo "Simple merge did not work, trying automatic merge."
git-merge-index -o git-merge-one-file -a ||
exit 2 ; # Automatic merge failed; should not be doing Octopus
next=$(git-write-tree 2>/dev/null)
fi
# We have merged the other branch successfully. Ideally
# we could implement OR'ed heads in merge-base, and keep
# a list of commits we have merged so far in MRC to feed
# them to merge-base, but we approximate it by keep using
# the current MRC. We used to update it to $common, which
# was incorrectly doing AND'ed merge-base here, which was
# unneeded.
MRT=$next
done
exit 0