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