Work around missing hard links on FAT formatted media
[git.git] / git-octopus.sh
1 #!/bin/sh
2 #
3 # Copyright (c) 2005 Junio C Hamano
4 #
5 # Resolve two or more trees recorded in $GIT_DIR/FETCH_HEAD.
6 #
7 . git-sh-setup || die "Not a git archive"
8
9 usage () {
10     die "usage: git octopus"
11 }
12
13 # Sanity check the heads early.
14 while read SHA1 REPO
15 do
16         test $(git-cat-file -t $SHA1) = "commit" ||
17                 die "$REPO given to octopus is not a commit"
18 done <"$GIT_DIR/FETCH_HEAD"
19
20 head=$(git-rev-parse --verify HEAD) || exit
21
22 git-update-index --refresh ||
23         die "Your working tree is dirty."
24 test "$(git-diff-index --cached "$head")" = "" ||
25         die "Your working tree does not match HEAD."
26
27 # MRC is the current "merge reference commit"
28 # MRT is the current "merge result tree"
29
30 MRC=$head PARENT="-p $head"
31 MRT=$(git-write-tree)
32 CNT=1 ;# counting our head
33 NON_FF_MERGE=0
34 while read SHA1 REPO
35 do
36         common=$(git-merge-base $MRC $SHA1) ||
37                 die "Unable to find common commit with $SHA1 from $REPO"
38
39         if test "$common" = $SHA1
40         then
41                 echo "Already up-to-date: $REPO"
42                 continue
43         fi
44
45         CNT=`expr $CNT + 1`
46         PARENT="$PARENT -p $SHA1"
47
48         if test "$common,$NON_FF_MERGE" = "$MRC,0"
49         then
50                 # The first head being merged was a fast-forward.
51                 # Advance MRC to the head being merged, and use that
52                 # tree as the intermediate result of the merge.
53                 # We still need to count this as part of the parent set.
54
55                 echo "Fast forwarding to: $REPO"
56                 git-read-tree -u -m $head $SHA1 || exit
57                 MRC=$SHA1 MRT=$(git-write-tree)
58                 continue
59         fi
60
61         NON_FF_MERGE=1
62
63         echo "Trying simple merge with $REPO"
64         git-read-tree -u -m $common $MRT $SHA1 || exit
65         next=$(git-write-tree 2>/dev/null)
66         if test $? -ne 0
67         then
68                 echo "Simple merge did not work, trying automatic merge."
69                 git-merge-index -o git-merge-one-file -a || {
70                 git-read-tree --reset "$head"
71                 git-checkout-index -f -q -u -a
72                 die "Automatic merge failed; should not be doing Octopus"
73                 }
74                 next=$(git-write-tree 2>/dev/null)
75         fi
76         MRC=$common
77         MRT=$next
78 done <"$GIT_DIR/FETCH_HEAD"
79
80 # Just to be careful in case the user feeds nonsense to us.
81 case "$CNT" in
82 1)
83         echo "No changes."
84         exit 0 ;;
85 esac
86 result_commit=$(git-fmt-merge-msg <"$GIT_DIR/FETCH_HEAD" |
87                 git-commit-tree $MRT $PARENT)
88 echo "Committed merge $result_commit"
89 git-update-ref HEAD $result_commit $head
90 git-diff-tree -p $head $result_commit | git-apply --stat