fix(kernel): Correctly return instances of un-exported types

packages/jsii-calc/lib/compliance.ts

@@ -1196,3 +1196,28 @@ export interface LoadBalancedFargateServiceProps {
      */
     publicTasks?: boolean;
 }
+
+/**
+ * Helps ensure the JSII kernel & runtime cooperate correctly when an un-exported instance of a class is returned with
+ * a declared type that is an exported interface, and the instance inherits from an exported class.
+ *
+ * @returns an instance of an un-exported class that extends ``ExportedBaseClass``, declared as ``IPrivatelyImplemented``.
+ *
+ * @see https://github.com/awslabs/jsii/issues/320
+ */
+export class ReturnsPrivateImplementationOfInterface {
+    public get privateImplementation(): IPrivatelyImplemented {
+        return new PrivateImplementation();
+    }
+}
+export interface IPrivatelyImplemented {
+    readonly success: boolean;
+}
+export class ExportedBaseClass {
+    constructor(public readonly success: boolean) {}
+}
+class PrivateImplementation extends ExportedBaseClass implements IPrivatelyImplemented {
+    constructor() {
+        super(true);
+    }
+}

packages/jsii-calc/test/assembly.jsii

@@ -1410,6 +1410,32 @@
       ],
       "name": "DoubleTrouble"
     },
+    "jsii-calc.ExportedBaseClass": {
+      "assembly": "jsii-calc",
+      "fqn": "jsii-calc.ExportedBaseClass",
+      "initializer": {
+        "initializer": true,
+        "parameters": [
+          {
+            "name": "success",
+            "type": {
+              "primitive": "boolean"
+            }
+          }
+        ]
+      },
+      "kind": "class",
+      "name": "ExportedBaseClass",
+      "properties": [
+        {
+          "immutable": true,
+          "name": "success",
+          "type": {
+            "primitive": "boolean"
+          }
+        }
+      ]
+    },
     "jsii-calc.GiveMeStructs": {
       "assembly": "jsii-calc",
       "fqn": "jsii-calc.GiveMeStructs",
@@ -1633,6 +1659,22 @@
       ],
       "name": "IInterfaceWithOptionalMethodArguments"
     },
+    "jsii-calc.IPrivatelyImplemented": {
+      "assembly": "jsii-calc",
+      "fqn": "jsii-calc.IPrivatelyImplemented",
+      "kind": "interface",
+      "name": "IPrivatelyImplemented",
+      "properties": [
+        {
+          "abstract": true,
+          "immutable": true,
+          "name": "success",
+          "type": {
+            "primitive": "boolean"
+          }
+        }
+      ]
+    },
     "jsii-calc.IRandomNumberGenerator": {
       "assembly": "jsii-calc",
       "docs": {
@@ -2825,6 +2867,29 @@
         }
       ]
     },
+    "jsii-calc.ReturnsPrivateImplementationOfInterface": {
+      "assembly": "jsii-calc",
+      "docs": {
+        "comment": "Helps ensure the JSII kernel & runtime cooperate correctly when an un-exported instance of a class is returned with\na declared type that is an exported interface, and the instance inherits from an exported class.",
+        "return": "an instance of an un-exported class that extends ``ExportedBaseClass``, declared as ``IPrivatelyImplemented``.",
+        "see": "https://github.com/awslabs/jsii/issues/320"
+      },
+      "fqn": "jsii-calc.ReturnsPrivateImplementationOfInterface",
+      "initializer": {
+        "initializer": true
+      },
+      "kind": "class",
+      "name": "ReturnsPrivateImplementationOfInterface",
+      "properties": [
+        {
+          "immutable": true,
+          "name": "privateImplementation",
+          "type": {
+            "fqn": "jsii-calc.IPrivatelyImplemented"
+          }
+        }
+      ]
+    },
     "jsii-calc.RuntimeTypeChecking": {
       "assembly": "jsii-calc",
       "fqn": "jsii-calc.RuntimeTypeChecking",
@@ -3671,5 +3736,5 @@
     }
   },
   "version": "0.7.11",
-  "fingerprint": "2o7FtEirv0LpuaJ1G+wAxoHTW7FHr4U1taZ5GcVYt2o="
+  "fingerprint": "Nw3vyHfzec4IFe674buqsgL3x8QgvKP0lUC3csRIW7g="
 }

packages/jsii-dotnet-runtime-test/test/Amazon.JSII.Runtime.IntegrationTests/ComplianceTests.cs

@@ -862,6 +862,12 @@ public void NullShouldBeTreatedAsUndefined()
             obj.VerifyPropertyIsUndefined();
         }
 
+        [Fact(DisplayName = Prefix + nameof(ReceiveInstanceOfPrivateClass))]
+        public void ReceiveInstanceOfPrivateClass()
+        {
+            Assert.True(new ReturnsPrivateImplementationOfInterface().PrivateImplementation.Success);
+        }
+
         class NumberReturner : DeputyBase, IIReturnsNumber
         {
             public NumberReturner(double number)

packages/jsii-java-runtime-test/project/src/test/java/software/amazon/jsii/testing/ComplianceTest.java

@@ -32,6 +32,7 @@
 import software.amazon.jsii.tests.calculator.Polymorphism;
 import software.amazon.jsii.tests.calculator.Power;
 import software.amazon.jsii.tests.calculator.ReferenceEnumFromScopedPackage;
+import software.amazon.jsii.tests.calculator.ReturnsPrivateImplementationOfInterface;
 import software.amazon.jsii.tests.calculator.Statics;
 import software.amazon.jsii.tests.calculator.Sum;
 import software.amazon.jsii.tests.calculator.SyncVirtualMethods;
@@ -953,6 +954,14 @@ public void nullShouldBeTreatedAsUndefined() {
         obj.verifyPropertyIsUndefined();
     }
 
+    /**
+     * @see https://github.com/awslabs/jsii/issues/320
+     */
+    @Test
+    public void receiveInstanceOfPrivateClass() {
+        assertTrue(new ReturnsPrivateImplementationOfInterface().getPrivateImplementation().getSuccess());
+    }
+
     static class MulTen extends Multiply {
         public MulTen(final int value) {
             super(new Number(value), new Number(10));

packages/jsii-java-runtime/pom.xml.t.js

@@ -80,7 +80,7 @@ process.stdout.write(`<?xml version="1.0" encoding="UTF-8"?>
         <dependency>
             <groupId>javax.annotation</groupId>
             <artifactId>javax.annotation-api</artifactId>
-            <version>[1.2,)</version>
+            <version>[1.3.2,)</version>
             <scope>provided</scope>
         </dependency>
     </dependencies>

packages/jsii-kernel/lib/kernel.ts

@@ -435,7 +435,12 @@ export class Kernel {
                 case spec.TypeKind.Class:
                 case spec.TypeKind.Enum:
                     const constructor = this._findSymbol(fqn);
-                    constructor.__jsii__ = { fqn };
+                    Object.defineProperty(constructor, '__jsii__', {
+                        configurable: false,
+                        enumerable: false,
+                        writable: false,
+                        value: { fqn }
+                    });
             }
         }
     }
@@ -956,7 +961,9 @@ export class Kernel {
             // have an object id, so we need to allocate one for it.
             this._debug('creating objref for', v);
             const fqn = this._fqnForObject(v);
-            return this._createObjref(v, fqn);
+            if (!targetType || !spec.isNamedTypeReference(targetType) || fqn === targetType.fqn) {
+                return this._createObjref(v, fqn);
+            }
         }
 
         // if the method/property returns an object literal and the return type

packages/jsii-pacmak/lib/targets/java.ts

@@ -389,7 +389,7 @@ class JavaGenerator extends Generator {
 
                     'properties': { 'project.build.sourceEncoding': 'UTF-8' },
 
-                    'dependencies': { dependency: mavenDependencies() },
+                    'dependencies': { dependency: mavenDependencies() },
 
                     'build': {
                         plugins: {

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/.jsii

@@ -1410,6 +1410,32 @@
       ],
       "name": "DoubleTrouble"
     },
+    "jsii-calc.ExportedBaseClass": {
+      "assembly": "jsii-calc",
+      "fqn": "jsii-calc.ExportedBaseClass",
+      "initializer": {
+        "initializer": true,
+        "parameters": [
+          {
+            "name": "success",
+            "type": {
+              "primitive": "boolean"
+            }
+          }
+        ]
+      },
+      "kind": "class",
+      "name": "ExportedBaseClass",
+      "properties": [
+        {
+          "immutable": true,
+          "name": "success",
+          "type": {
+            "primitive": "boolean"
+          }
+        }
+      ]
+    },
     "jsii-calc.GiveMeStructs": {
       "assembly": "jsii-calc",
       "fqn": "jsii-calc.GiveMeStructs",
@@ -1633,6 +1659,22 @@
       ],
       "name": "IInterfaceWithOptionalMethodArguments"
     },
+    "jsii-calc.IPrivatelyImplemented": {
+      "assembly": "jsii-calc",
+      "fqn": "jsii-calc.IPrivatelyImplemented",
+      "kind": "interface",
+      "name": "IPrivatelyImplemented",
+      "properties": [
+        {
+          "abstract": true,
+          "immutable": true,
+          "name": "success",
+          "type": {
+            "primitive": "boolean"
+          }
+        }
+      ]
+    },
     "jsii-calc.IRandomNumberGenerator": {
       "assembly": "jsii-calc",
       "docs": {
@@ -2825,6 +2867,29 @@
         }
       ]
     },
+    "jsii-calc.ReturnsPrivateImplementationOfInterface": {
+      "assembly": "jsii-calc",
+      "docs": {
+        "comment": "Helps ensure the JSII kernel & runtime cooperate correctly when an un-exported instance of a class is returned with\na declared type that is an exported interface, and the instance inherits from an exported class.",
+        "return": "an instance of an un-exported class that extends ``ExportedBaseClass``, declared as ``IPrivatelyImplemented``.",
+        "see": "https://github.com/awslabs/jsii/issues/320"
+      },
+      "fqn": "jsii-calc.ReturnsPrivateImplementationOfInterface",
+      "initializer": {
+        "initializer": true
+      },
+      "kind": "class",
+      "name": "ReturnsPrivateImplementationOfInterface",
+      "properties": [
+        {
+          "immutable": true,
+          "name": "privateImplementation",
+          "type": {
+            "fqn": "jsii-calc.IPrivatelyImplemented"
+          }
+        }
+      ]
+    },
     "jsii-calc.RuntimeTypeChecking": {
       "assembly": "jsii-calc",
       "fqn": "jsii-calc.RuntimeTypeChecking",
@@ -3671,5 +3736,5 @@
     }
   },
   "version": "0.7.11",
-  "fingerprint": "2o7FtEirv0LpuaJ1G+wAxoHTW7FHr4U1taZ5GcVYt2o="
+  "fingerprint": "Nw3vyHfzec4IFe674buqsgL3x8QgvKP0lUC3csRIW7g="
 }

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/ExportedBaseClass.cs

@@ -0,0 +1,26 @@
+using Amazon.JSII.Runtime.Deputy;
+
+namespace Amazon.JSII.Tests.CalculatorNamespace
+{
+    [JsiiClass(typeof(ExportedBaseClass), "jsii-calc.ExportedBaseClass", "[{\"name\":\"success\",\"type\":{\"primitive\":\"boolean\"}}]")]
+    public class ExportedBaseClass : DeputyBase
+    {
+        public ExportedBaseClass(bool success): base(new DeputyProps(new object[]{success}))
+        {
+        }
+
+        protected ExportedBaseClass(ByRefValue reference): base(reference)
+        {
+        }
+
+        protected ExportedBaseClass(DeputyProps props): base(props)
+        {
+        }
+
+        [JsiiProperty("success", "{\"primitive\":\"boolean\"}")]
+        public virtual bool Success
+        {
+            get => GetInstanceProperty<bool>();
+        }
+    }
+}

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/IIPrivatelyImplemented.cs

@@ -0,0 +1,14 @@
+using Amazon.JSII.Runtime.Deputy;
+
+namespace Amazon.JSII.Tests.CalculatorNamespace
+{
+    [JsiiInterface(typeof(IIPrivatelyImplemented), "jsii-calc.IPrivatelyImplemented")]
+    public interface IIPrivatelyImplemented
+    {
+        [JsiiProperty("success", "{\"primitive\":\"boolean\"}")]
+        bool Success
+        {
+            get;
+        }
+    }
+}

packages/jsii-pacmak/test/expected.jsii-calc/dotnet/Amazon.JSII.Tests.CalculatorPackageId/Amazon/JSII/Tests/CalculatorNamespace/IPrivatelyImplementedProxy.cs

@@ -0,0 +1,18 @@
+using Amazon.JSII.Runtime.Deputy;
+
+namespace Amazon.JSII.Tests.CalculatorNamespace
+{
+    [JsiiTypeProxy(typeof(IIPrivatelyImplemented), "jsii-calc.IPrivatelyImplemented")]
+    internal sealed class IPrivatelyImplementedProxy : DeputyBase, IIPrivatelyImplemented
+    {
+        private IPrivatelyImplementedProxy(ByRefValue reference): base(reference)
+        {
+        }
+
+        [JsiiProperty("success", "{\"primitive\":\"boolean\"}")]
+        public bool Success
+        {
+            get => GetInstanceProperty<bool>();
+        }
+    }
+}