#2891 Fix subclass mapping while superclass has non-empty constructor

Co-authored-by: Filip Hrisafov <filip.hrisafov@gmail.com>

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

@@ -704,6 +704,14 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
         }
 
         private ConstructorAccessor getConstructorAccessor(Type type) {
+            if ( type.isAbstract() ) {
+                // We cannot construct abstract classes.
+                // Usually we won't reach here,
+                // but if SubclassMapping is used with SubclassExhaustiveStrategy#RUNTIME_EXCEPTION
+                // then we will still generate the code.
+                // We shouldn't generate anything for those abstract types
+                return null;
+            }
 
             if ( type.isRecord() ) {
                 // If the type is a record then just get the record components and use then
@@ -1783,7 +1791,7 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
     }
 
     public boolean isAbstractReturnType() {
-        return getFactoryMethod() == null && !hasConstructorMappings() && returnTypeToConstruct != null
+        return getFactoryMethod() == null && returnTypeToConstruct != null
             && returnTypeToConstruct.isAbstract();
     }
 

processor/src/test/java/org/mapstruct/ap/test/bugs/_2891/Issue2891Mapper.java

@@ -0,0 +1,76 @@
+/*
+ * 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._2891;
+
+import org.mapstruct.BeanMapping;
+import org.mapstruct.Mapper;
+import org.mapstruct.SubclassExhaustiveStrategy;
+import org.mapstruct.SubclassMapping;
+
+/**
+ * @author Sergei Portnov
+ */
+@Mapper
+public interface Issue2891Mapper {
+
+    @BeanMapping(subclassExhaustiveStrategy = SubclassExhaustiveStrategy.RUNTIME_EXCEPTION)
+    @SubclassMapping(source = Source1.class, target = Target1.class)
+    @SubclassMapping(source = Source2.class, target = Target2.class)
+    AbstractTarget map(AbstractSource source);
+
+    abstract class AbstractTarget {
+
+        private final String name;
+
+        protected AbstractTarget(String name) {
+            this.name = name;
+        }
+
+        public String getName() {
+            return name;
+        }
+    }
+
+    class Target1 extends AbstractTarget {
+
+        protected Target1(String name) {
+            super( name );
+        }
+    }
+
+    class Target2 extends AbstractTarget {
+
+        protected Target2(String name) {
+            super( name );
+        }
+    }
+
+    abstract class AbstractSource {
+
+        private final String name;
+
+        protected AbstractSource(String name) {
+            this.name = name;
+        }
+
+        public String getName() {
+            return name;
+        }
+    }
+
+    class Source1 extends AbstractSource {
+        protected Source1(String name) {
+            super( name );
+        }
+    }
+
+    class Source2 extends AbstractSource {
+
+        protected Source2(String name) {
+            super( name );
+        }
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_2891/Issue2891Test.java

@@ -0,0 +1,30 @@
+/*
+ * 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._2891;
+
+import org.junit.jupiter.api.extension.RegisterExtension;
+import org.mapstruct.ap.testutil.IssueKey;
+import org.mapstruct.ap.testutil.ProcessorTest;
+import org.mapstruct.ap.testutil.WithClasses;
+import org.mapstruct.ap.testutil.runner.GeneratedSource;
+
+/**
+ * @author Sergei Portnov
+ */
+@WithClasses({
+    Issue2891Mapper.class
+})
+@IssueKey("2891")
+class Issue2891Test {
+
+    @RegisterExtension
+    final GeneratedSource generatedSource = new GeneratedSource()
+        .addComparisonToFixtureFor( Issue2891Mapper.class );
+
+    @ProcessorTest
+    void shouldCompile() {
+    }
+}

processor/src/test/resources/fixtures/org/mapstruct/ap/test/bugs/_2891/Issue2891MapperImpl.java

@@ -0,0 +1,61 @@
+/*
+ * 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._2891;
+
+import javax.annotation.processing.Generated;
+
+@Generated(
+    value = "org.mapstruct.ap.MappingProcessor",
+    date = "2022-06-18T14:48:32+0300",
+    comments = "version: , compiler: Eclipse JDT (Batch) 3.20.0.v20191203-2131, environment: Java 11.0.15.1 (BellSoft)"
+)
+public class Issue2891MapperImpl implements Issue2891Mapper {
+
+    @Override
+    public AbstractTarget map(AbstractSource source) {
+        if ( source == null ) {
+            return null;
+        }
+
+        if (source instanceof Source1) {
+            return source1ToTarget1( (Source1) source );
+        }
+        else if (source instanceof Source2) {
+            return source2ToTarget2( (Source2) source );
+        }
+        else {
+            throw new IllegalArgumentException("Not all subclasses are supported for this mapping. Missing for " + source.getClass());
+        }
+    }
+
+    protected Target1 source1ToTarget1(Source1 source1) {
+        if ( source1 == null ) {
+            return null;
+        }
+
+        String name = null;
+
+        name = source1.getName();
+
+        Target1 target1 = new Target1( name );
+
+        return target1;
+    }
+
+    protected Target2 source2ToTarget2(Source2 source2) {
+        if ( source2 == null ) {
+            return null;
+        }
+
+        String name = null;
+
+        name = source2.getName();
+
+        Target2 target2 = new Target2( name );
+
+        return target2;
+    }
+}