Don't notify observers of onDidChangeText after an empty transaction

spec/text-buffer-spec.coffee

@@ -2650,7 +2650,6 @@ describe "TextBuffer", ->
         buffer.insert([2, 3], "zw")
         buffer.delete([[2, 3], [2, 4]])
 
-
       assertChangesEqual(textChanges, [
         {
           oldRange: [[1, 0], [1, 0]],
@@ -2715,6 +2714,12 @@ describe "TextBuffer", ->
         }
       ])
 
+    it "doesn't notify observers after an empty transaction", ->
+      didChangeTextSpy = jasmine.createSpy()
+      buffer.onDidChangeText(didChangeTextSpy)
+      buffer.transact(->)
+      expect(didChangeTextSpy).not.toHaveBeenCalled()
+
     it "doesn't throw an error when clearing the undo stack within a transaction", ->
       buffer.onDidChangeText(didChangeTextSpy = jasmine.createSpy())
       expect(-> buffer.transact(-> buffer.clearUndoStack())).not.toThrowError()

src/text-buffer.coffee

@@ -1654,9 +1654,11 @@ class TextBuffer
   emitDidChangeTextEvent: (patch) ->
     return if @transactCallDepth isnt 0
 
-    @emitter.emit 'did-change-text', {changes: Object.freeze(normalizePatchChanges(patch.getHunks()))}
-    @patchesSinceLastStoppedChangingEvent.push(patch)
-    @scheduleDidStopChangingEvent()
+    hunks = patch.getHunks()
+    if hunks.length > 0
+      @emitter.emit 'did-change-text', {changes: Object.freeze(normalizePatchChanges(hunks))}
+      @patchesSinceLastStoppedChangingEvent.push(patch)
+      @scheduleDidStopChangingEvent()
 
   # Identifies if the buffer belongs to multiple editors.
   #