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         common=$(git merge-base --all $MRC $SHA1) ||
  65                 die "Unable to find common commit with $SHA1"
  66
  67         case "$LF$common$LF" in
  68         *"$LF$SHA1$LF"*)
  69                 echo "Already up-to-date with $SHA1"
  70                 continue
  71                 ;;
  72         esac
  73
  74         CNT=`expr $CNT + 1`
  75         PARENT="$PARENT -p $SHA1"
  76
  77         if test "$common,$NON_FF_MERGE" = "$MRC,0"
  78         then
  79                 # The first head being merged was a fast-forward.
  80                 # Advance MRC to the head being merged, and use that
  81                 # tree as the intermediate result of the merge.
  82                 # We still need to count this as part of the parent set.
  83
  84                 echo "Fast forwarding to: $SHA1"
  85                 git read-tree -u -m $head $SHA1 || exit
  86                 MRC=$SHA1 MRT=$(git write-tree)
  87                 continue
  88         fi
  89
  90         NON_FF_MERGE=1
  91
  92         echo "Trying simple merge with $SHA1"
  93         git read-tree -u -m --aggressive  $common $MRT $SHA1 || exit 2
  94         next=$(git write-tree 2>/dev/null)
  95         if test $? -ne 0
  96         then
  97                 echo "Simple merge did not work, trying automatic merge."
  98                 git merge-index -o git-merge-one-file -a ||
  99                 OCTOPUS_FAILURE=1
 100                 next=$(git write-tree 2>/dev/null)
 101         fi
 102
 103         # We have merged the other branch successfully.  Ideally
 104         # we could implement OR'ed heads in merge-base, and keep
 105         # a list of commits we have merged so far in MRC to feed
 106         # them to merge-base, but we approximate it by keep using
 107         # the current MRC.  We used to update it to $common, which
 108         # was incorrectly doing AND'ed merge-base here, which was
 109         # unneeded.
 110
 111         MRT=$next
 112 done
 113
 114 exit "$OCTOPUS_FAILURE"