Add open and override modifiers for class members

docs/modules/language-reference/pages/index.adoc

@@ -6028,7 +6028,7 @@ Here's a realistic example of how references might be used:
 import "pkl:ref"
 
 class Domain extends ref.Domain { // <1>
-  function renderReference(reference: ref.Reference<Domain, Any>): String =
+override function renderReference(reference: ref.Reference<Domain, Any>): String =
     if (reference.getData() is Task)
       let (path = reference.getPath().map((access) -> access.property ?? access.key.toString()))
         "${\(reference.getData().name)/\(path.join("/"))}"

docs/modules/release-notes/pages/0.32.adoc

@@ -63,7 +63,7 @@ Library authors describe types as `ref.Reference<D, T>`, where `D` is the _domai
 import "pkl:ref"
 
 class MyDomain extends ref.Domain { // <1>
-  function renderReference(ref: ref.Reference<MyDomain, Any>): String =
+override function renderReference(ref: ref.Reference<MyDomain, Any>): String =
     "${ " + ref.getData() + "." + ref.getPath().join(".") + " }"
 }
 

pkl-cli/src/test/kotlin/org/pkl/cli/CliCommandRunnerTest.kt

@@ -46,7 +46,7 @@ class CliCommandRunnerTest {
     """
     extends "pkl:Command"
 
-    options: Options
+    override options: Options
 
     output {
       value = options
@@ -822,7 +822,7 @@ class CliCommandRunnerTest {
         """
         extends "pkl:Command"
 
-        options: Options
+        override options: Options
 
         output {
           value = (options) {
@@ -875,7 +875,7 @@ class CliCommandRunnerTest {
         """
         extends "pkl:Command"
 
-        options: Options
+        override options: Options
 
         output {
           value = (options) {
@@ -935,7 +935,7 @@ class CliCommandRunnerTest {
         extends "pkl:Command"
         import "base.pkl"
 
-        options: Options
+        override options: Options
 
         output {
           value = (options) {

pkl-cli/src/test/kotlin/org/pkl/cli/CliEvaluatorTest.kt

@@ -1151,7 +1151,7 @@ result = someLib.x
         class Person {
           name: String
 
-          function toString() = "Person(\(name))"
+          override function toString() = "Person(\(name))"
         }
         person: Person = new { name = "Frodo" }
         """

pkl-codegen-java/src/test/kotlin/org/pkl/codegen/java/JavaCodeGeneratorTest.kt

@@ -1944,11 +1944,11 @@ class JavaCodeGeneratorTest {
         }
 
         open class OpenClass {
-          prop: Foo
+          open prop: Foo
         }
 
         class TheClass extends OpenClass {
-          prop: TheFoo
+          override prop: TheFoo
         }
         """
           .trimIndent()
@@ -1988,11 +1988,11 @@ class JavaCodeGeneratorTest {
         }
 
         open class OpenClass {
-          prop: Foo
+          open prop: Foo
         }
 
         class TheClass extends OpenClass {
-          prop: TheFoo
+          override prop: TheFoo
         }
         """
           .trimIndent(),

pkl-config-java/src/test/resources/codegenPkl/OverriddenProperty.pkl

@@ -1,7 +1,7 @@
 module com.example.OverriddenProperty
 
 abstract class BaseClass {
-  fixed bar: Listing<BaseBar> = new {
+  open fixed bar: Listing<BaseBar> = new {
     new {
       prop1 = "hello"
     }
@@ -11,7 +11,7 @@ abstract class BaseClass {
 theClass: TheClass
 
 class TheClass extends BaseClass {
-  fixed bar: Listing<Bar> = new {
+  override fixed bar: Listing<Bar> = new {
     new {
       prop1 = "hello"
       prop2 = "hello again"

pkl-config-kotlin/src/test/resources/codegenPkl/OverriddenProperty.pkl

@@ -1,7 +1,7 @@
 module com.example.OverriddenProperty
 
 abstract class BaseClass {
-  fixed bar: Listing<BaseBar> = new {
+  open fixed bar: Listing<BaseBar> = new {
     new {
       prop1 = "hello"
     }
@@ -11,7 +11,7 @@ abstract class BaseClass {
 theClass: TheClass
 
 class TheClass extends BaseClass {
-  fixed bar: Listing<Bar> = new {
+  override fixed bar: Listing<Bar> = new {
     new {
       prop1 = "hello"
       prop2 = "hello again"

pkl-core/src/main/java/org/pkl/core/ast/VmModifier.java

@@ -41,6 +41,8 @@ private VmModifier() {}
 
   public static final int CONST = 0x40;
 
+  public static final int OVERRIDE = 0x2000;
+
   // internal modifiers
 
   public static final int IMPORT = 0x80;
@@ -69,11 +71,12 @@ private VmModifier() {}
 
   public static final int VALID_TYPE_ALIAS_MODIFIERS = LOCAL | EXTERNAL;
 
-  public static final int VALID_METHOD_MODIFIERS = ABSTRACT | LOCAL | EXTERNAL | CONST;
+  public static final int VALID_METHOD_MODIFIERS =
+      ABSTRACT | LOCAL | EXTERNAL | CONST | OPEN | OVERRIDE;
 
   // for compat, properties may be parsed with abstract modifier but this is ignored
   public static final int VALID_PROPERTY_MODIFIERS =
-      ABSTRACT | LOCAL | HIDDEN | EXTERNAL | FIXED | CONST;
+      ABSTRACT | LOCAL | HIDDEN | EXTERNAL | FIXED | CONST | OPEN | OVERRIDE;
 
   public static final int VALID_OBJECT_MEMBER_MODIFIERS = LOCAL | CONST;
 
@@ -129,6 +132,10 @@ public static boolean isConst(int modifiers) {
     return (modifiers & CONST) != 0;
   }
 
+  public static boolean isOverride(int modifiers) {
+    return (modifiers & OVERRIDE) != 0;
+  }
+
   public static boolean isAmbiguousLocality(int modifiers) {
     return (modifiers & AMBIGUOUS_LOCALITY) != 0;
   }
@@ -186,6 +193,7 @@ public static String toString(int modifier) {
       case EXTERNAL -> "external";
       case FIXED -> "fixed";
       case CONST -> "const";
+      case OVERRIDE -> "override";
       default ->
           throw new VmExceptionBuilder()
               .bug("Cannot convert internal modifier `%s` to a string.", toString(modifier))
@@ -203,6 +211,7 @@ public static VmSet getMirrors(int modifiers, boolean isClass) {
     if (isExternal(modifiers) && isClass) builder.add(toString(EXTERNAL));
     if (isFixed(modifiers)) builder.add(toString(FIXED));
     if (isConst(modifiers)) builder.add(toString(CONST));
+    if (isOverride(modifiers)) builder.add(toString(OVERRIDE));
 
     return builder.build();
   }

pkl-core/src/main/java/org/pkl/core/ast/builder/AstBuilder.java

@@ -1857,6 +1857,7 @@ private int toModifier(Modifier modifier) {
       case HIDDEN -> VmModifier.HIDDEN;
       case FIXED -> VmModifier.FIXED;
       case CONST -> VmModifier.CONST;
+      case OVERRIDE -> VmModifier.OVERRIDE;
     };
   }
 

pkl-core/src/main/java/org/pkl/core/ast/member/ClassNode.java

@@ -123,37 +123,45 @@ public VmClass executeGeneric(VirtualFrame frame) {
             typeParameters,
             prototype);
 
-    if (unresolvedSupertypeNode != null) {
-      var supertypeNode = unresolvedSupertypeNode.execute(frame);
-      var superclass = supertypeNode.getVmClass();
+    var localContext = VmLanguage.get(this).localContext.get();
+    localContext.beginClassInit(cachedClass);
 
-      checkSupertype(supertypeNode, superclass);
-      cachedClass.initSupertype(supertypeNode, superclass);
-    }
+    try {
+      if (unresolvedSupertypeNode != null) {
+        var supertypeNode = unresolvedSupertypeNode.execute(frame);
+        var superclass = supertypeNode.getVmClass();
 
-    // The superclass resolved above may not itself have completed the below initializations yet.
-    // That's because these initializations may have indirectly or directly triggered
-    // resolution of this class, in which case the `resolveSuperclass()` call above
-    // will have returned the partially initialized `cachedClass` of the superclass.
-    // As a consequence, initializations that require a fully initialized class hierarchy
-    // are done lazily in VmClass rather than here.
-    // A fully initialized class hierarchy is only required for initialization of internal caches,
-    // which is guaranteed to succeed (no impact on eager vs. lazy error reporting) and easy to
-    // defer.
+        checkSupertype(supertypeNode, superclass);
+        cachedClass.initSupertype(supertypeNode, superclass);
+      }
 
-    VmUtils.evaluateAnnotations(frame, annotationNodes, annotations);
+      // The superclass resolved above may not itself have completed the below initializations yet.
+      // That's because these initializations may have indirectly or directly triggered
+      // resolution of this class, in which case the `resolveSuperclass()` call above
+      // will have returned the partially initialized `cachedClass` of the superclass.
+      // As a consequence, initializations that require a fully initialized class hierarchy
+      // are done lazily in VmClass rather than here.
+      // A fully initialized class hierarchy is only required for initialization of internal caches,
+      // which is guaranteed to succeed (no impact on eager vs. lazy error reporting) and easy to
+      // defer.
 
-    for (var node : unresolvedPropertyNodes) {
-      cachedClass.addProperty(node.execute(frame, cachedClass));
-    }
+      VmUtils.evaluateAnnotations(frame, annotationNodes, annotations);
 
-    for (var node : unresolvedMethodNodes) {
-      cachedClass.addMethod(node.execute(frame, cachedClass));
-    }
+      for (var node : unresolvedPropertyNodes) {
+        cachedClass.addProperty(node.execute(frame, cachedClass));
+      }
 
-    cachedClass.notifyInitialized();
+      for (var node : unresolvedMethodNodes) {
+        cachedClass.addMethod(node.execute(frame, cachedClass));
+      }
 
-    return cachedClass;
+      cachedClass.onOwnClassInitialized();
+      localContext.endClassInit();
+      return cachedClass;
+    } catch (Throwable e) {
+      localContext.clearClassInitState();
+      throw e;
+    }
   }
 
   private void checkSupertype(TypeNode supertypeNode, @Nullable VmClass superclass) {

pkl-core/src/main/java/org/pkl/core/ast/member/Member.java

@@ -130,4 +130,12 @@ public final boolean isConstOrFixed() {
   public final boolean isLocalOrExternalOrAbstract() {
     return VmModifier.isLocalOrExternalOrAbstract(modifiers);
   }
+
+  public final boolean isClosed() {
+    return VmModifier.isClosed(modifiers);
+  }
+
+  public final boolean isOverride() {
+    return VmModifier.isOverride(modifiers);
+  }
 }