1#!/bin/sh
2#
3# Copyright (c) 2005 Linus Torvalds
4#
5# Resolve two trees.
6#
7
8USAGE='<head> <remote> <merge-message>'
9. git-sh-setup
10
11dropheads() {
12 rm -f -- "$GIT_DIR/MERGE_HEAD" \
13 "$GIT_DIR/LAST_MERGE" || exit 1
14}
15
16head=$(git-rev-parse --verify "$1"^0) &&
17merge=$(git-rev-parse --verify "$2"^0) &&
18merge_msg="$3" || usage
19
20#
21# The remote name is just used for the message,
22# but we do want it.
23#
24if [ -z "$head" -o -z "$merge" -o -z "$merge_msg" ]; then
25 usage
26fi
27
28dropheads
29echo $head > "$GIT_DIR"/ORIG_HEAD
30echo $merge > "$GIT_DIR"/LAST_MERGE
31
32common=$(git-merge-base $head $merge)
33if [ -z "$common" ]; then
34 die "Unable to find common commit between" $merge $head
35fi
36
37case "$common" in
38"$merge")
39 echo "Already up-to-date. Yeeah!"
40 dropheads
41 exit 0
42 ;;
43"$head")
44 echo "Updating from $head to $merge."
45 git-read-tree -u -m $head $merge || exit 1
46 git-update-ref HEAD "$merge" "$head"
47 git-diff-tree -p $head $merge | git-apply --stat
48 dropheads
49 exit 0
50 ;;
51esac
52
53# We are going to make a new commit.
54git var GIT_COMMITTER_IDENT >/dev/null || exit
55
56# Find an optimum merge base if there are more than one candidates.
57LF='
58'
59common=$(git-merge-base -a $head $merge)
60case "$common" in
61?*"$LF"?*)
62 echo "Trying to find the optimum merge base."
63 G=.tmp-index$$
64 best=
65 best_cnt=-1
66 for c in $common
67 do
68 rm -f $G
69 GIT_INDEX_FILE=$G git-read-tree -m $c $head $merge \
70 2>/dev/null || continue
71 # Count the paths that are unmerged.
72 cnt=`GIT_INDEX_FILE=$G git-ls-files --unmerged | wc -l`
73 if test $best_cnt -le 0 -o $cnt -le $best_cnt
74 then
75 best=$c
76 best_cnt=$cnt
77 if test "$best_cnt" -eq 0
78 then
79 # Cannot do any better than all trivial merge.
80 break
81 fi
82 fi
83 done
84 rm -f $G
85 common="$best"
86esac
87
88echo "Trying to merge $merge into $head using $common."
89git-update-index --refresh 2>/dev/null
90git-read-tree -u -m $common $head $merge || exit 1
91result_tree=$(git-write-tree 2> /dev/null)
92if [ $? -ne 0 ]; then
93 echo "Simple merge failed, trying Automatic merge"
94 git-merge-index -o git-merge-one-file -a
95 if [ $? -ne 0 ]; then
96 echo $merge > "$GIT_DIR"/MERGE_HEAD
97 die "Automatic merge failed, fix up by hand"
98 fi
99 result_tree=$(git-write-tree) || exit 1
100fi
101result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree -p $head -p $merge)
102echo "Committed merge $result_commit"
103git-update-ref HEAD "$result_commit" "$head"
104git-diff-tree -p $head $result_commit | git-apply --stat
105dropheads