octopus: do not do AND'ed merge base.
[git/git.git] / git-merge-octopus.sh
1 #!/bin/sh
2 #
3 # Copyright (c) 2005 Junio C Hamano
4 #
5 # Resolve two or more trees.
6 #
7
8 LF='
9 '
10
11 # The first parameters up to -- are merge bases; the rest are heads.
12 bases= head= remotes= sep_seen=
13 for arg
14 do
15 case ",$sep_seen,$head,$arg," in
16 *,--,)
17 sep_seen=yes
18 ;;
19 ,yes,,*)
20 head=$arg
21 ;;
22 ,yes,*)
23 remotes="$remotes$arg "
24 ;;
25 *)
26 bases="$bases$arg "
27 ;;
28 esac
29 done
30
31 # Reject if this is not an Octopus -- resolve should be used instead.
32 case "$remotes" in
33 ?*' '?*)
34 ;;
35 *)
36 exit 2 ;;
37 esac
38
39 # MRC is the current "merge reference commit"
40 # MRT is the current "merge result tree"
41
42 MRC=$head MSG= PARENT="-p $head"
43 MRT=$(git-write-tree)
44 CNT=1 ;# counting our head
45 NON_FF_MERGE=0
46 for SHA1 in $remotes
47 do
48 common=$(git-merge-base --all $MRC $SHA1) ||
49 die "Unable to find common commit with $SHA1"
50
51 case "$common" in
52 ?*"$LF"?*)
53 die "Not trivially mergeable."
54 ;;
55 $SHA1)
56 echo "Already up-to-date with $SHA1"
57 continue
58 ;;
59 esac
60
61 CNT=`expr $CNT + 1`
62 PARENT="$PARENT -p $SHA1"
63
64 if test "$common,$NON_FF_MERGE" = "$MRC,0"
65 then
66 # The first head being merged was a fast-forward.
67 # Advance MRC to the head being merged, and use that
68 # tree as the intermediate result of the merge.
69 # We still need to count this as part of the parent set.
70
71 echo "Fast forwarding to: $SHA1"
72 git-read-tree -u -m $head $SHA1 || exit
73 MRC=$SHA1 MRT=$(git-write-tree)
74 continue
75 fi
76
77 NON_FF_MERGE=1
78
79 echo "Trying simple merge with $SHA1"
80 git-read-tree -u -m $common $MRT $SHA1 || exit 2
81 next=$(git-write-tree 2>/dev/null)
82 if test $? -ne 0
83 then
84 echo "Simple merge did not work, trying automatic merge."
85 git-merge-index -o git-merge-one-file -a ||
86 exit 2 ; # Automatic merge failed; should not be doing Octopus
87 next=$(git-write-tree 2>/dev/null)
88 fi
89
90 # We have merged the other branch successfully. Ideally
91 # we could implement OR'ed heads in merge-base, and keep
92 # a list of commits we have merged so far in MRC to feed
93 # them to merge-base, but we approximate it by keep using
94 # the current MRC. We used to update it to $common, which
95 # was incorrectly doing AND'ed merge-base here, which was
96 # unneeded.
97
98 MRT=$next
99 done
100
101 exit 0