Make event filtering stricter for events

core/block_dragger.js

@@ -225,8 +225,12 @@ Blockly.BlockDragger.prototype.endBlockDrag = function(e, currentDragDeltaXY) {
     this.draggingBlock_.moveConnections_(delta.x, delta.y);
     this.draggingBlock_.setDragging(false);
     this.fireMoveEvent_();
-    this.draggedConnectionManager_.applyConnections();
-    this.draggingBlock_.render();
+    if (this.draggedConnectionManager_.wouldConnectBlock()) {
+      // Applying connections also rerenders the relevant blocks.
+      this.draggedConnectionManager_.applyConnections();
+    } else {
+      this.draggingBlock_.render();
+    }
     this.draggingBlock_.scheduleSnapAndBump();
   }
   this.workspace_.setResizesEnabled(true);

core/dragged_connection_manager.js

@@ -125,6 +125,16 @@ Blockly.DraggedConnectionManager.prototype.wouldDeleteBlock = function() {
   return this.wouldDeleteBlock_;
 };
 
+/**
+ * Return whether the block would be deleted if dropped immediately, based on
+ * information from the most recent move event.
+ * @return {boolean} true if the block would be deleted if dropped immediately.
+ * @package
+ */
+Blockly.DraggedConnectionManager.prototype.wouldConnectBlock = function() {
+  return !!this.closestConnection_;
+};
+
 /**
  * Connect to the closest connection and render the results.
  * This should be called at the end of a drag.

core/events.js

@@ -204,15 +204,22 @@ Blockly.Events.filter = function(queueIn, forward) {
   for (var i = 0, event; event = queue[i]; i++) {
     if (!event.isNull()) {
       var key = [event.type, event.blockId, event.workspaceId].join(' ');
-      var lastEvent = hash[key];
-      if (!lastEvent) {
-        hash[key] = event;
+
+      var lastEntry = hash[key];
+      var lastEvent = lastEntry ? lastEntry.event : null;
+      if (!lastEntry) {
+        // Each item in the hash table has the event and the index of that event
+        // in the input array.  This lets us make sure we only merge adjacent
+        // move events.
+        hash[key] = { event: event, index: i};
         mergedQueue.push(event);
-      } else if (event.type == Blockly.Events.MOVE) {
+      } else if (event.type == Blockly.Events.MOVE &&
+          lastEntry.index == i - 1) {
         // Merge move events.
         lastEvent.newParentId = event.newParentId;
         lastEvent.newInputName = event.newInputName;
         lastEvent.newCoordinate = event.newCoordinate;
+        lastEntry.index = i;
       } else if (event.type == Blockly.Events.CHANGE &&
           event.element == lastEvent.element &&
           event.name == lastEvent.name) {
@@ -227,7 +234,7 @@ Blockly.Events.filter = function(queueIn, forward) {
         lastEvent.newValue = event.newValue;
       } else {
         // Collision: newer events should merge into this event to maintain order
-        hash[key] = event;
+        hash[key] = { event: event, index: 1};
         mergedQueue.push(event);
       }
     }

tests/jsunit/event_test.js

@@ -790,3 +790,30 @@ function test_events_newblock_newvar_xml() {
     Blockly.Events.fire = savedFireFunc;
   }
 }
+
+function test_events_filter_nomerge_move() {
+  // Move events should only merge if they refer to the same block and are
+  // consecutive.
+  eventTest_setUpWithMockBlocks();
+  try {
+    var block1 = createSimpleTestBlock(workspace);
+    var block2 = createSimpleTestBlock(workspace);
+
+    var events = [];
+    helper_addMoveEvent(events, block1, 1, 1);
+    helper_addMoveEvent(events, block2, 1, 1);
+    events.push(new Blockly.Events.BlockDelete(block2));
+    helper_addMoveEvent(events, block1, 2, 2);
+
+    var filteredEvents = Blockly.Events.filter(events, true);
+    // Nothing should have merged.
+    assertEquals(4, filteredEvents.length);
+    // test that the order hasn't changed
+    assertTrue(filteredEvents[0] instanceof Blockly.Events.BlockMove);
+    assertTrue(filteredEvents[1] instanceof Blockly.Events.BlockMove);
+    assertTrue(filteredEvents[2] instanceof Blockly.Events.BlockDelete);
+    assertTrue(filteredEvents[3] instanceof Blockly.Events.BlockMove);
+  } finally {
+    eventTest_tearDownWithMockBlocks();
+  }
+}