#3331 Do not handle defined mappings if the result type is abstract due to runtime exception subclass exhaustive strategy (#3487)

processor/src/main/java/org/mapstruct/ap/internal/model/BeanMappingMethod.java

@@ -284,10 +284,15 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
 
             initializeMappingReferencesIfNeeded( resultTypeToMap );
 
-            // map properties with mapping
-            boolean mappingErrorOccurred = handleDefinedMappings( resultTypeToMap );
-            if ( mappingErrorOccurred ) {
-                return null;
+            boolean shouldHandledDefinedMappings = shouldHandledDefinedMappings( resultTypeToMap );
+
+
+            if ( shouldHandledDefinedMappings ) {
+                // map properties with mapping
+                boolean mappingErrorOccurred = handleDefinedMappings( resultTypeToMap );
+                if ( mappingErrorOccurred ) {
+                    return null;
+                }
             }
 
             boolean applyImplicitMappings = !mappingReferences.isRestrictToDefinedMappings();
@@ -1045,6 +1050,36 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
             return (List<AnnotationValue>) av.getValue();
         }
 
+        /**
+         * Determine whether defined mappings should be handled on the result type.
+         * They should be, if any of the following is true:
+         * <ul>
+         *     <li>The {@code resultTypeToMap} is not abstract</li>
+         *     <li>There is a factory method</li>
+         *     <li>The method is an update method</li>
+         * </ul>
+         * Otherwise, it means that we have reached this because subclass mappings are being used
+         * and the chosen strategy is runtime exception.
+         *
+         * @param resultTypeToMap the type in which the defined target properties are defined
+         * @return {@code true} if defined mappings should be handled for the result type, {@code false} otherwise
+         */
+        private boolean shouldHandledDefinedMappings(Type resultTypeToMap) {
+            if ( !resultTypeToMap.isAbstract() ) {
+                return true;
+            }
+
+            if ( hasFactoryMethod ) {
+                return true;
+            }
+
+            if ( method.isUpdateMethod() ) {
+                return true;
+            }
+
+            return false;
+        }
+
         /**
          * Iterates over all defined mapping methods ({@code @Mapping(s)}), either directly given or inherited from the
          * inverse mapping method.

processor/src/test/java/org/mapstruct/ap/test/bugs/_3331/Issue3331Mapper.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._3331;
+
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.SubclassExhaustiveStrategy;
+import org.mapstruct.SubclassMapping;
+import org.mapstruct.factory.Mappers;
+
+/**
+ * @author Filip Hrisafov
+ */
+@Mapper(subclassExhaustiveStrategy = SubclassExhaustiveStrategy.RUNTIME_EXCEPTION)
+public interface Issue3331Mapper {
+
+    Issue3331Mapper INSTANCE = Mappers.getMapper( Issue3331Mapper.class );
+
+    @SubclassMapping(source = Vehicle.Car.class, target = VehicleDto.Car.class)
+    @SubclassMapping(source = Vehicle.Motorbike.class, target = VehicleDto.Motorbike.class)
+    @Mapping(target = "name", constant = "noname")
+    VehicleDto map(Vehicle vehicle);
+
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_3331/Issue3331Test.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._3331;
+
+import org.mapstruct.ap.testutil.IssueKey;
+import org.mapstruct.ap.testutil.ProcessorTest;
+import org.mapstruct.ap.testutil.WithClasses;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+/**
+ * @author Filip Hrisafov
+ */
+@IssueKey("3331")
+@WithClasses({
+    Issue3331Mapper.class,
+    Vehicle.class,
+    VehicleDto.class,
+})
+class Issue3331Test {
+
+    @ProcessorTest
+    void shouldCorrectCompileAndThrowExceptionOnRuntime() {
+        VehicleDto target = Issue3331Mapper.INSTANCE.map( new Vehicle.Car( "Test car", 4 ) );
+
+        assertThat( target.getName() ).isEqualTo( "noname" );
+        assertThat( target )
+            .isInstanceOfSatisfying( VehicleDto.Car.class, car -> {
+                assertThat( car.getNumOfDoors() ).isEqualTo( 4 );
+            } );
+
+        target = Issue3331Mapper.INSTANCE.map( new Vehicle.Motorbike( "Test bike", true ) );
+
+        assertThat( target.getName() ).isEqualTo( "noname" );
+        assertThat( target )
+            .isInstanceOfSatisfying( VehicleDto.Motorbike.class, bike -> {
+                assertThat( bike.isAllowedForMinor() ).isTrue();
+            } );
+
+        assertThatThrownBy( () -> Issue3331Mapper.INSTANCE.map( new Vehicle.Truck( "Test truck", 3 ) ) )
+            .isInstanceOf( IllegalArgumentException.class )
+            .hasMessage( "Not all subclasses are supported for this mapping. Missing for " + Vehicle.Truck.class );
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_3331/Vehicle.java

@@ -0,0 +1,64 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._3331;
+
+/**
+ * @author Filip Hrisafov
+ */
+public abstract class Vehicle {
+
+    private final String name;
+
+    protected Vehicle(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public static class Car extends Vehicle {
+
+        private final int numOfDoors;
+
+        public Car(String name, int numOfDoors) {
+            super( name );
+            this.numOfDoors = numOfDoors;
+        }
+
+        public int getNumOfDoors() {
+            return numOfDoors;
+        }
+    }
+
+    public static class Motorbike extends Vehicle {
+
+        private final boolean allowedForMinor;
+
+        public Motorbike(String name, boolean allowedForMinor) {
+            super( name );
+            this.allowedForMinor = allowedForMinor;
+        }
+
+        public boolean isAllowedForMinor() {
+            return allowedForMinor;
+        }
+    }
+
+    public static class Truck extends Vehicle {
+
+        private final int numOfAxis;
+
+        public Truck(String name, int numOfAxis) {
+            super( name );
+            this.numOfAxis = numOfAxis;
+        }
+
+        public int getNumOfAxis() {
+            return numOfAxis;
+        }
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_3331/VehicleDto.java

@@ -0,0 +1,51 @@
+/*
+ * Copyright MapStruct Authors.
+ *
+ * Licensed under the Apache License version 2.0, available at http://www.apache.org/licenses/LICENSE-2.0
+ */
+package org.mapstruct.ap.test.bugs._3331;
+
+/**
+ * @author Filip Hrisafov
+ */
+public abstract class VehicleDto {
+
+    private final String name;
+
+    protected VehicleDto(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public static class Car extends VehicleDto {
+
+        private final int numOfDoors;
+
+        public Car(String name, int numOfDoors) {
+            super( name );
+            this.numOfDoors = numOfDoors;
+        }
+
+        public int getNumOfDoors() {
+            return numOfDoors;
+        }
+    }
+
+    public static class Motorbike extends VehicleDto {
+
+        private final boolean allowedForMinor;
+
+        public Motorbike(String name, boolean allowedForMinor) {
+            super( name );
+            this.allowedForMinor = allowedForMinor;
+        }
+
+        public boolean isAllowedForMinor() {
+            return allowedForMinor;
+        }
+    }
+
+}