Multi-backend merge driver.

[git.git] / git-merge-octopus.sh

diff --git a/git-merge-octopus.sh b/git-merge-octopus.sh
new file mode 100755 (executable)
index 0000000..aa1cd2f
--- /dev/null
+++ b/git-merge-octopus.sh
@@ -0,0 +1,86 @@
+#!/bin/sh
+#
+# Copyright (c) 2005 Junio C Hamano
+#
+# Resolve two or more trees.
+#
+
+# The first parameters up to -- are merge bases; the rest are heads.
+bases= head= remotes= sep_seen=
+for arg
+do
+       case ",$sep_seen,$head,$arg," in
+       *,--,)
+               sep_seen=yes
+               ;;
+       ,yes,,*)
+               head=$arg
+               ;;
+       ,yes,*)
+               remotes="$remotes$arg "
+               ;;
+       *)
+               bases="$bases$arg "
+               ;;
+       esac
+done
+
+# Reject if this is not an Octopus -- resolve should be used instead.
+case "$remotes" in
+?*' '?*)
+       ;;
+*)
+       exit 2 ;;
+esac
+
+# MRC is the current "merge reference commit"
+# MRT is the current "merge result tree"
+
+MRC=$head MSG= PARENT="-p $head"
+MRT=$(git-write-tree)
+CNT=1 ;# counting our head
+NON_FF_MERGE=0
+for SHA1 in $remotes
+do
+       common=$(git-merge-base $MRC $SHA1) ||
+               die "Unable to find common commit with $SHA1"
+
+       if test "$common" = $SHA1
+       then
+               echo "Already up-to-date with $SHA1"
+               continue
+       fi
+
+       CNT=`expr $CNT + 1`
+       PARENT="$PARENT -p $SHA1"
+
+       if test "$common,$NON_FF_MERGE" = "$MRC,0"
+       then
+               # The first head being merged was a fast-forward.
+               # Advance MRC to the head being merged, and use that
+               # tree as the intermediate result of the merge.
+               # We still need to count this as part of the parent set.
+
+               echo "Fast forwarding to: $SHA1"
+               git-read-tree -u -m $head $SHA1 || exit
+               MRC=$SHA1 MRT=$(git-write-tree)
+               continue
+       fi
+
+       NON_FF_MERGE=1
+
+       echo "Trying simple merge with $SHA1"
+       git-read-tree -u -m $common $MRT $SHA1 || exit 2
+       next=$(git-write-tree 2>/dev/null)
+       if test $? -ne 0
+       then
+               echo "Simple merge did not work, trying automatic merge."
+               git-merge-index -o git-merge-one-file -a ||
+               exit 2 ; # Automatic merge failed; should not be doing Octopus
+               next=$(git-write-tree 2>/dev/null)
+       fi
+       MRC=$common
+       MRT=$next
+done
+
+exit 0