Support reverse patching in merge-to-branch.sh

tools/merge-to-branch.sh

Index: tools/merge-to-branch.sh
diff --git a/tools/merge-to-branch.sh b/tools/merge-to-branch.sh
index 49bf3e44896cefdb3d90d79d42276e87bcb19bbd..a52b450120a011e2e982b18a9306901e5d238bfe 100755
--- a/tools/merge-to-branch.sh
+++ b/tools/merge-to-branch.sh
@@ -49,6 +49,7 @@ OPTIONS:
   -h    Show this message
   -s    Specify the step where to start work. Default: 0.
   -p    Specify a patch file to apply as part of the merge
+  -r    Reverse specified patches
 EOF
 }
 
@@ -68,7 +69,7 @@ restore_patch_commit_hashes_if_unset() {
 
 ########## Option parsing
 
-while getopts ":hs:fp:" OPTION ; do
+while getopts ":hs:fp:r" OPTION ; do
   case $OPTION in
     h)  usage
         exit 0
@@ -77,6 +78,8 @@ while getopts ":hs:fp:" OPTION ; do
         ;;
     f)  rm -f "$ALREADY_MERGING_SENTINEL_FILE"
         ;;
+    r)  REVERSE_PATCH="--reverse"
+        ;;
     s)  START_STEP=$OPTARG
         ;;
     ?)  echo "Illegal option: -$OPTARG"
@@ -134,7 +137,13 @@ revisions associated with the patches."
   if [ -z "$REVISION_LIST" ] ; then
     NEW_COMMIT_MSG="Applied patch to $MERGE_TO_BRANCH branch."
   else
-    NEW_COMMIT_MSG="Merged$REVISION_LIST into $MERGE_TO_BRANCH branch."
+    if [ -n "$REVERSE_PATCH" ] ; then
+      NEW_COMMIT_MSG="Rollback of$REVISION_LIST in \
+$MERGE_TO_BRANCH branch."
+    else
+      NEW_COMMIT_MSG="Merged$REVISION_LIST into \
+$MERGE_TO_BRANCH branch."
+    fi;
   fi;
 
   echo "$NEW_COMMIT_MSG" > $COMMITMSG_FILE