IDEA-85100 Deleting wrapped lines with Ctrl+Y doen't work properly with "soft wrapped" lines

Correct processing for the empty document

java/java-tests/testSrc/com/intellij/codeInsight/DuplicateActionTest.groovy

@@ -1,3 +1,18 @@
+/*
+ * Copyright 2000-2012 JetBrains s.r.o.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 package com.intellij.codeInsight;
 
 
@@ -14,7 +29,7 @@ xxx<caret>
   }
 
   public void testEmpty() {
-    doTest '<caret>', "txt", '\n<caret>'
+    doTest '<caret>', "txt", '<caret>'
   }
 
   private void doTest(String before, @NonNls String ext, String after) {

platform/platform-impl/src/com/intellij/openapi/editor/actions/DuplicateAction.java

@@ -31,6 +31,7 @@ import com.intellij.openapi.editor.actionSystem.EditorAction;
 import com.intellij.openapi.editor.actionSystem.EditorWriteActionHandler;
 import com.intellij.openapi.editor.ex.util.EditorUtil;
 import com.intellij.openapi.util.Pair;
+import org.jetbrains.annotations.Nullable;
 
 public class DuplicateAction extends EditorAction {
   public DuplicateAction() {
@@ -68,6 +69,7 @@ public class DuplicateAction extends EditorAction {
     }
   }
 
+  @Nullable
   static Pair<Integer, Integer> duplicateLinesRange(Editor editor, Document document, VisualPosition rangeStart, VisualPosition rangeEnd) {
     Pair<LogicalPosition, LogicalPosition> lines = EditorUtil.calcSurroundingRange(editor, rangeStart, rangeEnd);
     int offset = editor.getCaretModel().getOffset();
@@ -76,6 +78,9 @@ public class DuplicateAction extends EditorAction {
     LogicalPosition nextLineStart = lines.second;
     int start = editor.logicalPositionToOffset(lineStart);
     int end = editor.logicalPositionToOffset(nextLineStart);
+    if (end <= start) {
+      return null;
+    }
     String s = document.getCharsSequence().subSequence(start, end).toString();
     final int lineToCheck = nextLineStart.line - 1;
 

platform/platform-impl/src/com/intellij/openapi/editor/actions/DuplicateLinesAction.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2000-2010 JetBrains s.r.o.
+ * Copyright 2000-2012 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -40,7 +40,9 @@ public class DuplicateLinesAction extends EditorAction {
         VisualPosition rangeEnd = editor.offsetToVisualPosition(Math.max(selStart, selEnd));
         final Pair<Integer,Integer> copiedRange =
           DuplicateAction.duplicateLinesRange(editor, editor.getDocument(), rangeStart, rangeEnd);
-        editor.getSelectionModel().setSelection(copiedRange.first, copiedRange.second);
+        if (copiedRange != null) {
+          editor.getSelectionModel().setSelection(copiedRange.first, copiedRange.second);
+        }
       }
       else {
         VisualPosition caretPos = editor.getCaretModel().getVisualPosition();