PsiClass.getDocComment: don't load AST when there's no doc comment

java/java-psi-impl/src/com/intellij/psi/impl/compiled/StubBuildingVisitor.java

@@ -99,7 +99,7 @@ public class StubBuildingVisitor<T> extends ClassVisitor {
     boolean isEnum = isSet(flags, Opcodes.ACC_ENUM);
     boolean isAnnotationType = isSet(flags, Opcodes.ACC_ANNOTATION);
     short stubFlags = PsiClassStubImpl.packFlags(isDeprecated, isInterface, isEnum, false, false,
-                                                 isAnnotationType, false, false, myAnonymousInner, myLocalClassInner);
+                                                 isAnnotationType, false, false, myAnonymousInner, myLocalClassInner, false);
     myResult = new PsiClassStubImpl(JavaStubElementTypes.CLASS, myParent, fqn, shortName, null, stubFlags);
 
     myModList = new PsiModifierListStubImpl(myResult, packClassFlags(flags));

java/java-psi-impl/src/com/intellij/psi/impl/java/stubs/JavaClassElementType.java

@@ -77,6 +77,7 @@ public abstract class JavaClassElementType extends JavaStubElementType<PsiClassS
     boolean isAnnotation = false;
     boolean isInQualifiedNew = false;
     boolean hasDeprecatedAnnotation = false;
+    boolean hasDocComment = false;
 
     String qualifiedName = null;
     String name = null;
@@ -93,6 +94,7 @@ public abstract class JavaClassElementType extends JavaStubElementType<PsiClassS
     for (final LighterASTNode child : tree.getChildren(node)) {
       final IElementType type = child.getTokenType();
       if (type == JavaDocElementType.DOC_COMMENT) {
+        hasDocComment = true;
         isDeprecatedByComment = RecordUtil.isDeprecatedByDocComment(tree, child);
       }
       else if (type == JavaElementType.MODIFIER_LIST) {
@@ -134,7 +136,7 @@ public abstract class JavaClassElementType extends JavaStubElementType<PsiClassS
     }
 
     final short flags = PsiClassStubImpl.packFlags(isDeprecatedByComment, isInterface, isEnum, isEnumConst, isAnonymous, isAnnotation,
-                                                  isInQualifiedNew, hasDeprecatedAnnotation, false, false);
+                                                  isInQualifiedNew, hasDeprecatedAnnotation, false, false, hasDocComment);
     final JavaClassElementType type = typeForClass(isAnonymous, isEnumConst);
     return new PsiClassStubImpl(type, parentStub, qualifiedName, name, baseRef, flags);
   }

java/java-psi-impl/src/com/intellij/psi/impl/java/stubs/PsiClassStub.java

@@ -44,6 +44,10 @@ public interface PsiClassStub<T extends PsiClass> extends PsiMemberStub<T> {
 
   boolean isAnnotationType();
 
+  default boolean hasDocComment() {
+    return true;
+  }
+
   @Nullable
   String getSourceFileName();
 

java/java-psi-impl/src/com/intellij/psi/impl/java/stubs/impl/PsiClassStubImpl.java

@@ -42,6 +42,7 @@ public class PsiClassStubImpl<T extends PsiClass> extends StubBase<T> implements
   private static final int DEPRECATED_ANNOTATION = 0x80;
   private static final int ANONYMOUS_INNER = 0x100;
   private static final int LOCAL_CLASS_INNER = 0x200;
+  private static final int HAS_DOC_COMMENT = 0x400;
 
   private final String myQualifiedName;
   private final String myName;
@@ -124,6 +125,11 @@ public class PsiClassStubImpl<T extends PsiClass> extends StubBase<T> implements
     return BitUtil.isSet(myFlags, ANON_TYPE);
   }
 
+  @Override
+  public boolean hasDocComment() {
+    return BitUtil.isSet(myFlags, HAS_DOC_COMMENT);
+  }
+
   @Override
   public LanguageLevel getLanguageLevel() {
     StubElement parent = getParentStub();
@@ -163,7 +169,8 @@ public class PsiClassStubImpl<T extends PsiClass> extends StubBase<T> implements
                                boolean isInQualifiedNew,
                                boolean hasDeprecatedAnnotation, 
                                boolean anonymousInner,
-                               boolean localClassInner
+                               boolean localClassInner,
+                               boolean hasDocComment
                                 ) {
     short flags = 0;
     if (isDeprecated) flags |= DEPRECATED;
@@ -176,6 +183,7 @@ public class PsiClassStubImpl<T extends PsiClass> extends StubBase<T> implements
     if (hasDeprecatedAnnotation) flags |= DEPRECATED_ANNOTATION;
     if (anonymousInner) flags |= ANONYMOUS_INNER;
     if (localClassInner) flags |= LOCAL_CLASS_INNER;
+    if (hasDocComment) flags |= HAS_DOC_COMMENT;
     return flags;
   }
 

java/java-psi-impl/src/com/intellij/psi/impl/source/JavaFileElementType.java

@@ -29,7 +29,6 @@ import com.intellij.psi.impl.source.tree.java.JavaFileElement;
 import com.intellij.psi.stubs.*;
 import com.intellij.psi.tree.ILightStubFileElementType;
 import com.intellij.util.diff.FlyweightCapableTreeStructure;
-import com.intellij.util.io.StringRef;
 import org.jetbrains.annotations.NotNull;
 
 import java.io.IOException;
@@ -38,7 +37,7 @@ import java.io.IOException;
  * @author max
  */
 public class JavaFileElementType extends ILightStubFileElementType<PsiJavaFileStub> {
-  public static final int STUB_VERSION = 41;
+  public static final int STUB_VERSION = 42;
 
   public JavaFileElementType() {
     super("java.FILE", JavaLanguage.INSTANCE);

java/java-psi-impl/src/com/intellij/psi/impl/source/PsiClassImpl.java

@@ -419,6 +419,9 @@ public class PsiClassImpl extends JavaStubPsiElement<PsiClassStub<?>> implements
 
   @Override
   public PsiDocComment getDocComment(){
+    PsiClassStub<?> stub = getGreenStub();
+    if (stub != null && !stub.hasDocComment()) return null;
+
     return (PsiDocComment)getNode().findChildByRoleAsPsiElement(ChildRole.DOC_COMMENT);
   }