Merge pull request #4930 from andrewnester/fix-4784

fix: The editor can be crashed by passing in undefined into the setValue method

src/document.js

@@ -46,7 +46,7 @@ var Document = function(textOrLines) {
     this.setValue = function(text) {
         var len = this.getLength() - 1;
         this.remove(new Range(0, 0, len, this.getLine(len).length));
-        this.insert({row: 0, column: 0}, text);
+        this.insert({row: 0, column: 0}, text || "");
     };
 
     /**

src/edit_session_test.js

@@ -498,6 +498,21 @@ module.exports = {
         assert.equal(session.$foldData.length, 0);
     },
 
+    "test setting undefined value": function() {
+        var session = createFoldTestSession();
+        var editor = new Editor(new MockRenderer(), session);
+        editor.setOption("mode", new JavaScriptMode());
+
+        editor.setValue("test");
+        assert.equal(session.getValue(), "test");
+
+        editor.setValue(undefined);
+        assert.equal(session.getValue(), "");
+
+        editor.setValue("test");
+        assert.equal(session.getValue(), "test");
+    },
+
     "test foldOther": function() {
         var session = new EditSession("{\n\t1{\n\t\t\n\t\t1.1 {\n\t\t}\n\t}\n\t2 {\n\t\t2.1 {\n\t\t\t2.2 {\n\t\t\t}\n\t\t\t2.3 {\n\t\t\t}\n\t\t}\n\t}\n}\n\n{\n}");
         var editor = new Editor(new MockRenderer(), session);