tailOffset degraded in class name completion (EA-24778)

java/java-impl/src/com/intellij/codeInsight/completion/ConstructorInsertHandler.java

@@ -53,7 +53,7 @@ class ConstructorInsertHandler implements InsertHandler<LookupElementDecorator<L
 
     insertParentheses(context, delegate, delegate.getObject(), withTail && isAbstract);
 
-    DefaultInsertHandler.addImportForItem(context.getFile(), context.getStartOffset(), delegate);
+    DefaultInsertHandler.addImportForItem(context, delegate);
 
 
     if (withTail) {

java/java-impl/src/com/intellij/codeInsight/completion/DefaultInsertHandler.java

@@ -24,6 +24,7 @@ import com.intellij.featureStatistics.FeatureUsageTracker;
 import com.intellij.openapi.diagnostic.Logger;
 import com.intellij.openapi.editor.Document;
 import com.intellij.openapi.editor.Editor;
+import com.intellij.openapi.editor.RangeMarker;
 import com.intellij.openapi.project.Project;
 import com.intellij.openapi.util.text.StringUtil;
 import com.intellij.psi.*;
@@ -116,7 +117,7 @@ public class DefaultInsertHandler extends TemplateInsertHandler implements Clone
           }
         }
       }
-      addImportForItem(file, context.getStartOffset(), item);
+      addImportForItem(context, item);
       if (context.getTailOffset() < 0) {  //hack, hack, hack. ideally the tail offset just should survive after the importing stuff
         context.setTailOffset(context.getEditor().getCaretModel().getOffset());
       }
@@ -241,9 +242,11 @@ public class DefaultInsertHandler extends TemplateInsertHandler implements Clone
     JavaCompletionUtil.initOffsets(file, file.getProject(), offsetMap);
   }
 
-  public static void addImportForItem(PsiFile file, int startOffset, LookupElement item) throws IncorrectOperationException {
-    PsiDocumentManager.getInstance(file.getProject()).commitAllDocuments();
+  public static void addImportForItem(InsertionContext context, LookupElement item) throws IncorrectOperationException {
+    PsiDocumentManager.getInstance(context.getProject()).commitAllDocuments();
 
+    int startOffset = context.getStartOffset();
+    PsiFile file = context.getFile();
     Object o = item.getObject();
     if (o instanceof PsiClass){
       PsiClass aClass = (PsiClass)o;
@@ -252,8 +255,11 @@ public class DefaultInsertHandler extends TemplateInsertHandler implements Clone
       int length = lookupString.length();
       final int i = lookupString.indexOf('<');
       if (i >= 0) length = i;
+      RangeMarker savedTail = context.getDocument().createRangeMarker(context.getTailOffset(), context.getTailOffset());
       final int newOffset = addImportForClass(file, startOffset, startOffset + length, aClass);
       JavaCompletionUtil.shortenReference(file, newOffset);
+      assert savedTail.isValid();
+      context.setTailOffset(savedTail.getStartOffset());
     }
     else if (o instanceof PsiType){
       PsiType type = ((PsiType)o).getDeepComponentType();

java/java-impl/src/com/intellij/codeInsight/completion/JavaClassNameInsertHandler.java

@@ -98,7 +98,7 @@ class JavaClassNameInsertHandler implements InsertHandler<JavaPsiClassReferenceE
 
     LOG.assertTrue(context.getTailOffset() >= 0);
     String docText = context.getDocument().getText();
-    DefaultInsertHandler.addImportForItem(context.getFile(), context.getStartOffset(), item);
+    DefaultInsertHandler.addImportForItem(context, item);
     if (context.getTailOffset() < 0) {
       if (ApplicationManagerEx.getApplicationEx().isInternal()) {
         LOG.error("Tail offset degraded: " + context.getStartOffset() + "; " + docText);

java/java-impl/src/com/intellij/codeInsight/lookup/PsiTypeLookupItem.java

@@ -37,7 +37,7 @@ public class PsiTypeLookupItem extends LookupItem {
 
   @Override
   public void handleInsert(InsertionContext context) {
-    DefaultInsertHandler.addImportForItem(context.getFile(), context.getStartOffset(), this);
+    DefaultInsertHandler.addImportForItem(context, this);
     super.handleInsert(context);
   }
 

java/java-tests/testData/codeInsight/completion/normal/ClassNameInsideIdentifierInIf.java

@@ -0,0 +1,6 @@
+public class Bar {
+    {
+        if (2 != InpStrRea<caret>Aaa) {
+        }
+    }
+}

java/java-tests/testData/codeInsight/completion/normal/ClassNameInsideIdentifierInIf_after.java

@@ -0,0 +1,8 @@
+import java.io.InputStreamReader;
+
+public class Bar {
+    {
+        if (2 != InputStreamReader<caret>Aaa) {
+        }
+    }
+}

java/java-tests/testSrc/com/intellij/codeInsight/completion/NormalCompletionTest.groovy

@@ -842,6 +842,12 @@ public class NormalCompletionTest extends LightFixtureCompletionTestCase {
     assertStringItems("myField1", "myField2");
   }
 
+  public void testClassNameInsideIdentifierInIf() throws Throwable {
+    configure()
+    type '\n'
+    checkResult()
+  }
+
   public void testSuggestMembersOfStaticallyImportedClasses() throws Exception {
     myFixture.addClass("""package foo;
     public class Foo {