#3165 Support adders for array / iterable to collection

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

@@ -527,7 +527,7 @@ public class PropertyMapping extends ModelElement {
             Assignment result = rightHandSide;
 
             String adderIteratorName = sourcePropertyName == null ? targetPropertyName : sourcePropertyName;
-            if ( result.getSourceType().isCollectionType() ) {
+            if ( result.getSourceType().isIterableType() ) {
                 result = new AdderWrapper( result, method.getThrownTypes(), isFieldAssignment(), adderIteratorName );
             }
             else if ( result.getSourceType().isStreamType() ) {

processor/src/main/java/org/mapstruct/ap/internal/model/assignment/AdderWrapper.java

@@ -39,7 +39,15 @@ public class AdderWrapper extends AssignmentWrapper {
         // localVar is iteratorVariable
         String desiredName = Nouns.singularize( adderIteratorName );
         rhs.setSourceLoopVarName( rhs.createUniqueVarName( desiredName ) );
-        adderType = first( getSourceType().determineTypeArguments( Collection.class ) );
+        if ( getSourceType().isCollectionType() ) {
+            adderType = first( getSourceType().determineTypeArguments( Collection.class ) );
+        }
+        else if ( getSourceType().isArrayType() ) {
+            adderType = getSourceType().getComponentType();
+        }
+        else { // iterable
+            adderType = first( getSourceType().determineTypeArguments( Iterable.class ) );
+        }
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/internal/model/common/SourceRHS.java

@@ -149,6 +149,12 @@ public class SourceRHS extends ModelElement implements Assignment {
             else if ( sourceType.isStreamType() ) {
                 return first( sourceType.determineTypeArguments( Stream.class ) );
             }
+            else if ( sourceType.isArrayType() ) {
+                return sourceType.getComponentType();
+            }
+            else if ( sourceType.isIterableType() ) {
+                return first( sourceType.determineTypeArguments( Iterable.class ) );
+            }
         }
         return sourceType;
     }

processor/src/test/java/org/mapstruct/ap/test/bugs/_3165/Issue3165Mapper.java

@@ -0,0 +1,65 @@
+/*
+ * 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._3165;
+
+import org.mapstruct.CollectionMappingStrategy;
+import org.mapstruct.Mapper;
+import org.mapstruct.factory.Mappers;
+
+import java.util.ArrayList;
+import java.util.List;
+
+@Mapper(collectionMappingStrategy = CollectionMappingStrategy.ADDER_PREFERRED)
+public interface Issue3165Mapper {
+
+    Issue3165Mapper INSTANCE = Mappers.getMapper( Issue3165Mapper.class );
+
+    Target toTarget(Source source);
+
+    class Source {
+        private String[] pets;
+        private Iterable<String> cats;
+
+        public Source(String[] pets, Iterable<String> cats) {
+            this.pets = pets;
+            this.cats = cats;
+        }
+
+        public String[] getPets() {
+            return pets;
+        }
+
+        public Iterable<String> getCats() {
+            return cats;
+        }
+    }
+
+    class Target {
+        private List<String> pets;
+        private List<String> cats;
+
+        Target() {
+            this.pets = new ArrayList<>();
+            this.cats = new ArrayList<>();
+        }
+
+        public List<String> getPets() {
+            return pets;
+        }
+
+        public void addPet(String pet) {
+            pets.add( pet );
+        }
+
+        public List<String> getCats() {
+            return cats;
+        }
+
+        public void addCat(String cat) {
+            cats.add( cat );
+        }
+    }
+}

processor/src/test/java/org/mapstruct/ap/test/bugs/_3165/Issue3165MapperTest.java

@@ -0,0 +1,32 @@
+/*
+ * 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._3165;
+
+import java.util.Arrays;
+
+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;
+
+@WithClasses({
+    Issue3165Mapper.class
+})
+@IssueKey("3165")
+class Issue3165MapperTest {
+
+    @ProcessorTest
+    void supportsAdderWhenMappingArrayAndIterableToCollection() {
+        Issue3165Mapper.Source src = new Issue3165Mapper.Source(
+            new String[] { "cat", "dog", "mouse" },
+            Arrays.asList( "ivy", "flu", "freya" )
+        );
+        Issue3165Mapper.Target target = Issue3165Mapper.INSTANCE.toTarget( src );
+        assertThat( target.getPets() ).containsExactly( "cat", "dog", "mouse" );
+        assertThat( target.getCats() ).containsExactly( "ivy", "flu", "freya" );
+    }
+}