octopus: make merge process simpler to follow
[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 die () {
12 echo >&2 "$*"
13 exit 1
14 }
15
16 # The first parameters up to -- are merge bases; the rest are heads.
17 bases= head= remotes= sep_seen=
18 for arg
19 do
20 case ",$sep_seen,$head,$arg," in
21 *,--,)
22 sep_seen=yes
23 ;;
24 ,yes,,*)
25 head=$arg
26 ;;
27 ,yes,*)
28 remotes="$remotes$arg "
29 ;;
30 *)
31 bases="$bases$arg "
32 ;;
33 esac
34 done
35
36 # Reject if this is not an Octopus -- resolve should be used instead.
37 case "$remotes" in
38 ?*' '?*)
39 ;;
40 *)
41 exit 2 ;;
42 esac
43
44 # MRC is the current "merge reference commit"
45 # MRT is the current "merge result tree"
46
47 MRC=$head MSG= PARENT="-p $head"
48 MRT=$(git write-tree)
49 CNT=1 ;# counting our head
50 NON_FF_MERGE=0
51 OCTOPUS_FAILURE=0
52 for SHA1 in $remotes
53 do
54 case "$OCTOPUS_FAILURE" in
55 1)
56 # We allow only last one to have a hand-resolvable
57 # conflicts. Last round failed and we still had
58 # a head to merge.
59 echo "Automated merge did not work."
60 echo "Should not be doing an Octopus."
61 exit 2
62 esac
63
64 eval pretty_name=\${GITHEAD_$SHA1:-$SHA1}
65 common=$(git merge-base --all $SHA1 $MRC) ||
66 die "Unable to find common commit with $pretty_name"
67
68 case "$LF$common$LF" in
69 *"$LF$SHA1$LF"*)
70 echo "Already up-to-date with $pretty_name"
71 continue
72 ;;
73 esac
74
75 CNT=`expr $CNT + 1`
76 PARENT="$PARENT -p $SHA1"
77
78 if test "$common,$NON_FF_MERGE" = "$MRC,0"
79 then
80 # The first head being merged was a fast-forward.
81 # Advance MRC to the head being merged, and use that
82 # tree as the intermediate result of the merge.
83 # We still need to count this as part of the parent set.
84
85 echo "Fast-forwarding to: $pretty_name"
86 git read-tree -u -m $head $SHA1 || exit
87 MRC=$SHA1 MRT=$(git write-tree)
88 continue
89 fi
90
91 NON_FF_MERGE=1
92
93 echo "Trying simple merge with $pretty_name"
94 git read-tree -u -m --aggressive $common $MRT $SHA1 || exit 2
95 next=$(git write-tree 2>/dev/null)
96 if test $? -ne 0
97 then
98 echo "Simple merge did not work, trying automatic merge."
99 git-merge-index -o git-merge-one-file -a ||
100 OCTOPUS_FAILURE=1
101 next=$(git write-tree 2>/dev/null)
102 fi
103
104 MRC="$MRC $SHA1"
105 MRT=$next
106 done
107
108 exit "$OCTOPUS_FAILURE"