IDEA-59439 Adding 8-th line of code resize editor gutter if line numbers are shown

Corrected soft wraps processing during typing at document end

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

@@ -256,9 +256,9 @@ public class CachingSoftWrapDataMapper implements SoftWrapDataMapper, SoftWrapAw
     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;
+      cacheEntry.endLogicalColumn += context.symbolWidthInColumns;
+      cacheEntry.endVisualColumn += context.symbolWidthInColumns;
+      cacheEntry.endOffset++;
     }
   }
 
@@ -424,6 +424,20 @@ public class CachingSoftWrapDataMapper implements SoftWrapDataMapper, SoftWrapAw
 
     myNotAffectedByUpdateTailCacheEntries.clear();
     myNotAffectedByUpdateTailCacheEntries.addAll(myCache.subList(myBeforeChangeState.endCacheEntryIndex + 1, myCache.size()));
+    
+    // There is a possible case that the change is non-line feed symbol insertion to the document's end and its previous symbol
+    // is line feed. E.g.:
+    //    line1
+    //    line2
+    //    <caret>
+    // We stored cache entry that corresponds to offset just before the previous last symbol (line feed). However, last symbol is
+    // not line feed now, hence, we need to remove corresponding virtual cache entry.
+    int textLength = myEditor.getDocument().getTextLength();
+    if (endOffset >= textLength && !myNotAffectedByUpdateTailCacheEntries.isEmpty() 
+        && myNotAffectedByUpdateTailCacheEntries.get(myNotAffectedByUpdateTailCacheEntries.size() - 1).startOffset >= textLength) 
+    {
+      myNotAffectedByUpdateTailCacheEntries.remove(myNotAffectedByUpdateTailCacheEntries.size() - 1);
+    }
     myCache.subList(myBeforeChangeState.startCacheEntryIndex + 1, myCache.size()).clear();
     for (CacheEntry entry : myNotAffectedByUpdateTailCacheEntries) {
       entry.locked = true;

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

@@ -41,7 +41,7 @@ public class MappingUtil {
    *                  <code>-1</code> if it's not possible to perform such mapping
    */
   public static int getCacheEntryIndexForOffset(int offset, Document document, List<CacheEntry> cache) {
-    if (offset >= document.getTextLength()) {
+    if (offset >= document.getTextLength() && (cache.isEmpty() || cache.get(cache.size() - 1).endOffset < offset)) {
       if (cache.isEmpty()) {
         return -1;
       }

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

@@ -158,6 +158,22 @@ public class SoftWrapApplianceOnDocumentModificationTest extends LightPlatformCo
     // Don't expect any exceptions here.
   }
 
+  public void testTypeNewLastLineAndSymbolOnIt() throws IOException {
+    // Inspired by IDEA-59439
+    String text = 
+      "This is a test document\n" +
+      "line1\n" +
+      "line2\n" +
+      "line3\n" +
+      "line4\n" +
+      "line5\n" +
+      "line6<caret>";
+    
+    init(700, text);
+    type("\nq");
+    assertEquals(new VisualPosition(7, 1), myEditor.offsetToVisualPosition(myEditor.getDocument().getTextLength()));
+  }
+  
   //private void init(final int visibleWidth) throws Exception {
   //  configureByFile(PATH + getFileName());
   //  initCommon(visibleWidth);