IDEA-59306 Soft wrap: Throwable at CaretModelImpl.moveToOffset() on inserting tab in last empty line in editor

1. Corrected soft wraps cache recalculation in order to take into account document position after the last symbol;
2. Corresponding test is added (com.intellij.openapi.editor.impl.softwrap.mapping.SoftWrapApplianceOnDocumentModificationTest.testTypingTabOnLastEmptyLine());

java/java-tests/testData/codeInsight/softwrap/LongLineOfIdSymbolsIsNotSoftWrapped.txt

@@ -1,3 +0,0 @@
-abcdefghijklmnopqrstuvwxyz<caret>
-123
-ABCDEFGHIJKLMNOPQRSTUVWXYZ

java/java-tests/testData/codeInsight/softwrap/SoftWrapAdditionOnTyping.txt

@@ -1 +0,0 @@
-this is a test string that is expected to end just before right margin<caret>

platform/platform-impl/src/com/intellij/openapi/editor/impl/softwrap/mapping/CachingSoftWrapDataMapper.java

@@ -251,6 +251,15 @@ public class CachingSoftWrapDataMapper implements SoftWrapDataMapper, SoftWrapAw
       case '\t': onTabulation(context); break;
       default: onNonLineFeedSymbol(context); break;
     }
+
+    int documentLength = myEditor.getDocument().getTextLength();
+    if (documentLength > 0 && context.offset >= documentLength - 1 && context.symbol != '\n') {
+      // Update information about end position of the last visual line.
+      CacheEntry cacheEntry = getCacheEntryForVisualLine(context.visualLine);
+      cacheEntry.endLogicalColumn = context.logicalColumn + context.symbolWidthInColumns - 1; // -1 because the first context's
+                                                                                              // column already points to the symbol
+      cacheEntry.endVisualColumn = context.visualColumn + context.symbolWidthInColumns - 1;
+    }
   }
 
   @Override

platform/platform-impl/src/com/intellij/openapi/editor/impl/softwrap/mapping/OffsetToLogicalCalculationStrategy.java

@@ -70,17 +70,6 @@ class OffsetToLogicalCalculationStrategy extends AbstractMappingStrategy<Logical
       }
       return;
     }
-    else if (!cache.isEmpty()) {
-      CacheEntry lastEntry = cache.get(cache.size() - 1);
-      if (targetOffset > lastEntry.endOffset) {
-        LogicalPosition eager = new LogicalPosition(
-          lastEntry.endLogicalLine + 1, 0, lastEntry.endSoftWrapLinesBefore + lastEntry.endSoftWrapLinesCurrent,
-          0, 0, lastEntry.endFoldedLines, 0
-        );
-        setEagerMatch(eager);
-        return;
-      }
-    }
 
     int i = MappingUtil.getCacheEntryIndexForOffset(targetOffset, myEditor.getDocument(), cache);
     setCacheEntry(cache.get(i));

platform/platform-impl/src/com/intellij/openapi/editor/impl/softwrap/mapping/SoftWrapApplianceManager.java

@@ -291,7 +291,7 @@ public class SoftWrapApplianceManager implements FoldingListener, DocumentListen
           newX = calculateNewX(context, fontType, contentComponent);
         }
 
-        if (newX + reservedWidth >= myVisibleAreaWidth) {
+        if (newX + reservedWidth >= myVisibleAreaWidth && delayedSoftWrap == null) {
           logicalLineData.update(i, spaceWidth);
           SoftWrap softWrap = registerSoftWrap(
             softWrapStartOffset, Math.max(softWrapStartOffset, i - 1),

platform/platform-impl/testSrc/com/intellij/openapi/editor/impl/softwrap/mapping/SoftWrapApplianceOnDocumentModificationTest.java

@@ -17,10 +17,8 @@ package com.intellij.openapi.editor.impl.softwrap.mapping;
 
 import com.intellij.openapi.editor.FoldRegion;
 import com.intellij.openapi.editor.FoldingModel;
-import com.intellij.openapi.editor.LogicalPosition;
 import com.intellij.openapi.editor.VisualPosition;
 import com.intellij.openapi.editor.ex.SoftWrapModelEx;
-import com.intellij.openapi.editor.impl.FoldRegionImpl;
 import com.intellij.openapi.editor.impl.SoftWrapModelImpl;
 import com.intellij.testFramework.LightPlatformCodeInsightTestCase;
 
@@ -31,9 +29,9 @@ import java.io.IOException;
  * @author Denis Zhdanov
  * @since 09/16/2010
  */
-public class SoftWrapApplianceManagerTest extends LightPlatformCodeInsightTestCase {
+public class SoftWrapApplianceOnDocumentModificationTest extends LightPlatformCodeInsightTestCase {
 
-  private static final String PATH = "/codeInsight/softwrap/";
+  //private static final String PATH = "/codeInsight/softwrap/";
 
   @Override
   protected void tearDown() throws Exception {
@@ -42,7 +40,9 @@ public class SoftWrapApplianceManagerTest extends LightPlatformCodeInsightTestCa
   }
 
   public void testSoftWrapAdditionOnTyping() throws Exception {
-    init(800);
+    String text =
+      "this is a test string that is expected to end just before right margin<caret>";
+    init(800, text);
 
     int offset = myEditor.getDocument().getTextLength() + 1;
     assertTrue(getSoftWrapModel().getRegisteredSoftWraps().isEmpty());
@@ -51,7 +51,12 @@ public class SoftWrapApplianceManagerTest extends LightPlatformCodeInsightTestCa
   }
 
   public void testLongLineOfIdSymbolsIsNotSoftWrapped() throws Exception {
-    init(100);
+    String text =
+      "abcdefghijklmnopqrstuvwxyz<caret>\n" +
+      "123\n" +
+      "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
+
+    init(100, text);
     assertTrue(getSoftWrapModel().getRegisteredSoftWraps().isEmpty());
     type('1');
     assertTrue(getSoftWrapModel().getRegisteredSoftWraps().isEmpty());
@@ -130,11 +135,22 @@ public class SoftWrapApplianceManagerTest extends LightPlatformCodeInsightTestCa
     assertEquals(new VisualPosition(5, 0), myEditor.getCaretModel().getVisualPosition());
   }
 
-  private void init(final int visibleWidth) throws Exception {
-    configureByFile(PATH + getFileName());
-    initCommon(visibleWidth);
+  public void testTypingTabOnLastEmptyLine() throws IOException {
+    String text =
+      "class Test {\n" +
+      "}\n" +
+      "<caret>";
+
+    init(300, text);
+    type('\t');
+    assertEquals(new VisualPosition(2, 4), myEditor.getCaretModel().getVisualPosition());
   }
 
+  //private void init(final int visibleWidth) throws Exception {
+  //  configureByFile(PATH + getFileName());
+  //  initCommon(visibleWidth);
+  //}
+
   private void init(int visibleWidth, String fileText) throws IOException {
     configureFromFileText(getFileName(), fileText);
     initCommon(visibleWidth);