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[git.git] / git-resolve.sh
1 #!/bin/sh
2 #
3 # Copyright (c) 2005 Linus Torvalds
4 #
5 # Resolve two trees.
6 #
7
8 USAGE='<head> <remote> <merge-message>'
9 . git-sh-setup
10
11 dropheads() {
12         rm -f -- "$GIT_DIR/MERGE_HEAD" \
13                 "$GIT_DIR/LAST_MERGE" || exit 1
14 }
15
16 head=$(git-rev-parse --verify "$1"^0) &&
17 merge=$(git-rev-parse --verify "$2"^0) &&
18 merge_msg="$3" || usage
19
20 #
21 # The remote name is just used for the message,
22 # but we do want it.
23 #
24 if [ -z "$head" -o -z "$merge" -o -z "$merge_msg" ]; then
25         usage
26 fi
27
28 dropheads
29 echo $head > "$GIT_DIR"/ORIG_HEAD
30 echo $merge > "$GIT_DIR"/LAST_MERGE
31
32 common=$(git-merge-base $head $merge)
33 if [ -z "$common" ]; then
34         die "Unable to find common commit between" $merge $head
35 fi
36
37 case "$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 $merge | git-apply --stat
48         dropheads
49         exit 0
50         ;;
51 esac
52
53 # We are going to make a new commit.
54 git var GIT_COMMITTER_IDENT >/dev/null || exit
55
56 # Find an optimum merge base if there are more than one candidates.
57 LF='
58 '
59 common=$(git-merge-base -a $head $merge)
60 case "$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"
86 esac
87
88 echo "Trying to merge $merge into $head using $common."
89 git-update-index --refresh 2>/dev/null
90 git-read-tree -u -m $common $head $merge || exit 1
91 result_tree=$(git-write-tree  2> /dev/null)
92 if [ $? -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=$(git-write-tree) || exit 1
100 fi
101 result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree -p $head -p $merge)
102 echo "Committed merge $result_commit"
103 git-update-ref HEAD "$result_commit" "$head"
104 git-diff-tree -p $head $result_commit | git-apply --stat
105 dropheads