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