1 files changed, 17 insertions, 1 deletions
diff --git a/git/merge.sh b/git/merge.sh
index 4f12f8c..34da466 100755
--- a/git/merge.sh
+++ b/git/merge.sh
@@ -15,6 +15,22 @@ fi
 for i in $modules; do
   echo "merge $i" 1>&2
   cd $i
-  git merge $*
+
+  br=`git symbolic-ref -q HEAD`
+  br=`echo $br | sed -e 's%^refs/heads/%%'`
+
+  # Only allow fast-forward merges into master.
+  #
+  if [ "$br" = "master" ]; then
+    git merge --ff-only $*
+  else
+    git merge $*
+  fi
+
+  if [ $? -ne 0 ]; then
+    echo "merge FAILED" 1>&2
+    exit 1
+  fi
+
   cd $wd
 done