fix bug in the document's insert method

src/ace/Document.js

@@ -358,11 +358,11 @@ ace.Document = function(text, mode) {
         }
         else {
             var line = this.lines[position.row] || "";
+            var firstLine = line.substring(0, position.column) + newLines[0];
+            var lastLine = newLines[newLines.length - 1] + line.substring(position.column);
 
-            this.lines[position.row] = line.substring(0, position.column)
-                    + newLines[0];
-            this.lines[position.row + 1] = newLines[newLines.length - 1]
-                    + line.substring(position.column);
+            this.lines[position.row] = firstLine;
+            this.$insertLines(position.row + 1, [lastLine]);
 
             if (newLines.length > 2) {
                 this.$insertLines(position.row + 1, newLines.slice(1, -1));

src/ace/lib/lang.js

@@ -57,6 +57,11 @@
             }
           },
 
+          call: function() {
+              this.cancel();
+              fcn();
+          },
+
           cancel: function() {
               clearTimeout(timer);
               timer = null;

src/test/DocumentTest.js

@@ -123,5 +123,27 @@ var TextDocumentTest = new TestCase("TextDocumentTest", {
             end: {row: 2, column: 1}
         }, ["4", "5", "6"].join("\n"));
         assertEquals(["4", "5", "6"].join("\n"), doc.toString());
+    },
+
+    "test: undo/redo for delete line" : function() {
+        var doc = new ace.Document(["111", "222", "333"]);
+        var undoManager = new ace.UndoManager();
+        doc.setUndoManager(undoManager);
+
+        var initialText = doc.toString();
+
+        var editor = new ace.Editor(new MockRenderer(), doc);
+
+        editor.removeLines();
+        var removedText = doc.toString();
+
+        // call normally async code now
+        doc.$informUndoManager.call();
+
+        undoManager.undo();
+        assertEquals(initialText, doc.toString());
+
+        undoManager.redo();
+        assertEquals(removedText, doc.toString());
     }
 });