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 $merge | git-apply --stat
48 dropheads
49 exit 0
50 ;;
51esac
52
53# Find an optimum merge base if there are more than one candidates.
54LF='
55'
56common=$(git-merge-base -a $head $merge)
57case "$common" in
58?*"$LF"?*)
59 echo "Trying to find the optimum merge base."
60 G=.tmp-index$$
61 best=
62 best_cnt=-1
63 for c in $common
64 do
65 rm -f $G
66 GIT_INDEX_FILE=$G git-read-tree -m $c $head $merge \
67 2>/dev/null || continue
68 # Count the paths that are unmerged.
69 cnt=`GIT_INDEX_FILE=$G git-ls-files --unmerged | wc -l`
70 if test $best_cnt -le 0 -o $cnt -le $best_cnt
71 then
72 best=$c
73 best_cnt=$cnt
74 if test "$best_cnt" -eq 0
75 then
76 # Cannot do any better than all trivial merge.
77 break
78 fi
79 fi
80 done
81 rm -f $G
82 common="$best"
83esac
84
85echo "Trying to merge $merge into $head using $common."
86git-update-index --refresh 2>/dev/null
87git-read-tree -u -m $common $head $merge || exit 1
88result_tree=$(git-write-tree 2> /dev/null)
89if [ $? -ne 0 ]; then
90 echo "Simple merge failed, trying Automatic merge"
91 git-merge-index -o git-merge-one-file -a
92 if [ $? -ne 0 ]; then
93 echo $merge > "$GIT_DIR"/MERGE_HEAD
94 die "Automatic merge failed, fix up by hand"
95 fi
96 result_tree=$(git-write-tree) || exit 1
97fi
98result_commit=$(echo "$merge_msg" | git-commit-tree $result_tree -p $head -p $merge)
99echo "Committed merge $result_commit"
100git-update-ref HEAD "$result_commit" "$head"
101git-diff-tree -p $head $result_commit | git-apply --stat
102dropheads