mapstruct · filiphr · May 25, 2025 · May 13, 2025 · May 17, 2025 · May 17, 2025
diff --git a/processor/src/main/java/org/mapstruct/ap/MappingProcessor.java b/processor/src/main/java/org/mapstruct/ap/MappingProcessor.java
@@ -95,6 +95,7 @@
     MappingProcessor.VERBOSE,
     MappingProcessor.NULL_VALUE_ITERABLE_MAPPING_STRATEGY,
     MappingProcessor.NULL_VALUE_MAP_MAPPING_STRATEGY,
+    MappingProcessor.DISABLE_LIFECYCLE_OVERLOAD_DEDUPLICATE_SELECTOR,
 })
 public class MappingProcessor extends AbstractProcessor {
 
@@ -115,6 +116,8 @@ public class MappingProcessor extends AbstractProcessor {
     protected static final String VERBOSE = "mapstruct.verbose";
     protected static final String NULL_VALUE_ITERABLE_MAPPING_STRATEGY = "mapstruct.nullValueIterableMappingStrategy";
     protected static final String NULL_VALUE_MAP_MAPPING_STRATEGY = "mapstruct.nullValueMapMappingStrategy";
+    protected static final String DISABLE_LIFECYCLE_OVERLOAD_DEDUPLICATE_SELECTOR =
+        "mapstruct.disableLifecycleOverloadDeduplicateSelector";
 
     private final Set<String> additionalSupportedOptions;
     private final String additionalSupportedOptionsError;
@@ -174,6 +177,8 @@ private Options createOptions() {
         String nullValueIterableMappingStrategy = processingEnv.getOptions()
             .get( NULL_VALUE_ITERABLE_MAPPING_STRATEGY );
         String nullValueMapMappingStrategy = processingEnv.getOptions().get( NULL_VALUE_MAP_MAPPING_STRATEGY );
+        String disableLifecycleOverloadDeduplicateSelector = processingEnv.getOptions()
+            .get( DISABLE_LIFECYCLE_OVERLOAD_DEDUPLICATE_SELECTOR );
 
         return new Options(
             Boolean.parseBoolean( processingEnv.getOptions().get( SUPPRESS_GENERATOR_TIMESTAMP ) ),
@@ -189,7 +194,8 @@ private Options createOptions() {
                 NullValueMappingStrategyGem.valueOf( nullValueIterableMappingStrategy.toUpperCase( Locale.ROOT ) ) :
                 null,
             nullValueMapMappingStrategy != null ?
-                NullValueMappingStrategyGem.valueOf( nullValueMapMappingStrategy.toUpperCase( Locale.ROOT ) ) : null
+                NullValueMappingStrategyGem.valueOf( nullValueMapMappingStrategy.toUpperCase( Locale.ROOT ) ) : null,
+            Boolean.parseBoolean( disableLifecycleOverloadDeduplicateSelector )
         );
     }
 

diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/LifecycleMethodResolver.java b/processor/src/main/java/org/mapstruct/ap/internal/model/LifecycleMethodResolver.java
@@ -133,7 +133,7 @@ private static List<LifecycleCallbackMethodReference> collectLifecycleCallbackMe
             MappingBuilderContext ctx, Set<String> existingVariableNames) {
 
         MethodSelectors selectors =
-            new MethodSelectors( ctx.getTypeUtils(), ctx.getElementUtils(), ctx.getMessager() );
+            new MethodSelectors( ctx.getTypeUtils(), ctx.getElementUtils(), ctx.getMessager(), ctx.getOptions() );
 
         List<SelectedMethod<SourceMethod>> matchingMethods = selectors.getMatchingMethods(
             callbackMethods,

diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/ObjectFactoryMethodResolver.java b/processor/src/main/java/org/mapstruct/ap/internal/model/ObjectFactoryMethodResolver.java
@@ -5,12 +5,9 @@
  */
 package org.mapstruct.ap.internal.model;
 
-import static org.mapstruct.ap.internal.util.Collections.first;
-
 import java.util.ArrayList;
 import java.util.List;
 import java.util.stream.Collectors;
-
 import javax.lang.model.element.ElementKind;
 import javax.lang.model.element.ExecutableElement;
 
@@ -26,6 +23,8 @@
 import org.mapstruct.ap.internal.model.source.selector.SelectionContext;
 import org.mapstruct.ap.internal.util.Message;
 
+import static org.mapstruct.ap.internal.util.Collections.first;
+
 /**
  *
  * @author Sjaak Derksen
@@ -126,7 +125,7 @@ public static List<SelectedMethod<SourceMethod>> getMatchingFactoryMethods( Meth
         MappingBuilderContext ctx) {
 
         MethodSelectors selectors =
-            new MethodSelectors( ctx.getTypeUtils(), ctx.getElementUtils(), ctx.getMessager() );
+            new MethodSelectors( ctx.getTypeUtils(), ctx.getElementUtils(), ctx.getMessager(), null );
 
         return selectors.getMatchingMethods(
             getAllAvailableMethods( method, ctx.getSourceModel() ),

diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/PresenceCheckMethodResolver.java b/processor/src/main/java/org/mapstruct/ap/internal/model/PresenceCheckMethodResolver.java
@@ -119,7 +119,8 @@ private static List<SelectedMethod<SourceMethod>> findMatchingMethods(
         MethodSelectors selectors = new MethodSelectors(
             ctx.getTypeUtils(),
             ctx.getElementUtils(),
-            ctx.getMessager()
+            ctx.getMessager(),
+            null
         );
 
         return selectors.getMatchingMethods(

diff --git a/...org/mapstruct/ap/internal/model/source/selector/LifecycleOverloadDeduplicateSelector.java b/...org/mapstruct/ap/internal/model/source/selector/LifecycleOverloadDeduplicateSelector.java
@@ -0,0 +1,129 @@
+/*
+ * 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.internal.model.source.selector;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.stream.Collectors;
+
+import org.mapstruct.ap.internal.model.common.Parameter;
+import org.mapstruct.ap.internal.model.common.ParameterBinding;
+import org.mapstruct.ap.internal.model.source.Method;
+
+/**
+ * Selector for deduplicating overloaded lifecycle callback methods
+ * whose parameter signatures differ only by type hierarchy.
+ * <p>
+ * In the context of lifecycle callback method selection
+ * (such as @BeforeMapping or @AfterMapping), it is possible to have multiple overloaded methods
+ * whose parameter lists are structurally identical except for the specific types,
+ * where those types are related by inheritance (e.g., one parameter is a superclass or subclass of another).
+ * <p>
+ * This selector groups such methods by their effective parameter signature
+ * (ignoring differences only in type hierarchy), and, within each group,
+ * retains only the method whose parameter types have the closest inheritance distance
+ * to the actual invocation types.
+ * This ensures that, for each group of nearly identical overloads,
+ * only the most specific and appropriate method is selected.
+ * <p>
+ * <b>Example (see Issue3849Test):</b>
+ *
+ * <pre>{@code
+ * @AfterMapping
+ * default void afterMapping(Parent source, @MappingTarget ParentDto target) { ... }
+ * @AfterMapping
+ * default void afterMapping(Parent source, @MappingTarget ChildDto target) { ... }
+ * }</pre>
+ * When mapping a Child to a ChildDto,
+ * only the method with ChildDto is selected, even though both methods match by signature
+ * except for the target type's inheritance relationship.
+ */
+public class LifecycleOverloadDeduplicateSelector implements MethodSelector {
+    @Override
+    public <T extends Method> List<SelectedMethod<T>> getMatchingMethods(List<SelectedMethod<T>> methods,
+                                                                         SelectionContext context) {
+        if ( !context.getSelectionCriteria().isLifecycleCallbackRequired() || methods.size() <= 1 ) {
+            return methods;
+        }
+        Collection<List<SelectedMethod<T>>> methodSignatureGroups =
+            methods.stream()
+                .collect( Collectors.groupingBy(
+                    LifecycleOverloadDeduplicateSelector::buildSignatureKey,
+                    LinkedHashMap::new,
+                    Collectors.toList()
+                ) )
+                .values();
+        List<SelectedMethod<T>> deduplicatedMethods = new ArrayList<>( methods.size() );
+        for ( List<SelectedMethod<T>> signatureGroup : methodSignatureGroups ) {
+            if ( signatureGroup.size() == 1 ) {
+                deduplicatedMethods.add( signatureGroup.get( 0 ) );
+                continue;
+            }
+            SelectedMethod<T> bestInheritanceMethod = signatureGroup.get( 0 );
+            for ( int i = 1; i < signatureGroup.size(); i++ ) {
+                SelectedMethod<T> candidateMethod = signatureGroup.get( i );
+                if ( isInheritanceBetter( candidateMethod, bestInheritanceMethod ) ) {
+                    bestInheritanceMethod = candidateMethod;
+                }
+            }
+            deduplicatedMethods.add( bestInheritanceMethod );
+        }
+        return deduplicatedMethods;
+    }
+
+    /**
+     * Builds a grouping key for a method based on its defining type,
+     * method name, and a detailed breakdown of each parameter binding.
+     * <p>
+     * The key consists of:
+     * <ul>
+     *   <li>The type that defines the method</li>
+     *   <li>The method name</li>
+     *   <li>parameter bindings</li>
+     * </ul>
+     * This ensures that methods are grouped together only if all these aspects match,
+     * except for differences in type hierarchy, which are handled separately.
+     */
+    private static <T extends Method> List<Object> buildSignatureKey(SelectedMethod<T> method) {
+        List<Object> key = new ArrayList<>();
+        key.add( method.getMethod().getDefiningType() );
+        key.add( method.getMethod().getName() );
+        for ( ParameterBinding binding : method.getParameterBindings() ) {
+            key.add( binding.getType() );
+            key.add( binding.getVariableName() );
+        }
+        return key;
+    }
+
+    /**
+     * Compare the inheritance distance of parameters between two methods to determine if candidateMethod is better.
+     * Compares parameters in order, returns as soon as a better one is found.
+     */
+    private <T extends Method> boolean isInheritanceBetter(SelectedMethod<T> candidateMethod,
+                                                           SelectedMethod<T> currentBestMethod) {
+        List<ParameterBinding> candidateBindings = candidateMethod.getParameterBindings();
+        List<ParameterBinding> bestBindings = currentBestMethod.getParameterBindings();
+        List<Parameter> candidateParams = candidateMethod.getMethod().getParameters();
+        List<Parameter> bestParams = currentBestMethod.getMethod().getParameters();
+        int paramCount = candidateBindings.size();
+
+        for ( int i = 0; i < paramCount; i++ ) {
+            int candidateDistance = candidateBindings.get( i )
+                .getType()
+                .distanceTo( candidateParams.get( i ).getType() );
+            int bestDistance = bestBindings.get( i ).getType().distanceTo( bestParams.get( i ).getType() );
+            if ( candidateDistance < bestDistance ) {
+                return true;
+            }
+            else if ( candidateDistance > bestDistance ) {
+                return false;
+            }
+        }
+        return false;
+    }
+}
diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/source/selector/MethodSelectors.java b/processor/src/main/java/org/mapstruct/ap/internal/model/source/selector/MethodSelectors.java
@@ -10,6 +10,7 @@
 import java.util.List;
 
 import org.mapstruct.ap.internal.model.source.Method;
+import org.mapstruct.ap.internal.option.Options;
 import org.mapstruct.ap.internal.util.ElementUtils;
 import org.mapstruct.ap.internal.util.FormattingMessager;
 import org.mapstruct.ap.internal.util.TypeUtils;
@@ -24,20 +25,27 @@ public class MethodSelectors {
     private final List<MethodSelector> selectors;
 
     public MethodSelectors(TypeUtils typeUtils, ElementUtils elementUtils,
-                           FormattingMessager messager) {
-        selectors = Arrays.asList(
+                           FormattingMessager messager, Options options) {
+        List<MethodSelector> selectorList = new ArrayList<>( Arrays.asList(
             new MethodFamilySelector(),
             new TypeSelector( messager ),
             new QualifierSelector( typeUtils, elementUtils ),
             new TargetTypeSelector( typeUtils ),
             new JavaxXmlElementDeclSelector( typeUtils ),
             new JakartaXmlElementDeclSelector( typeUtils ),
-            new InheritanceSelector(),
+            new InheritanceSelector()
+        ) );
+        if ( options != null && !options.isDisableLifecycleOverloadDeduplicateSelector() ) {
+            selectorList.add( new LifecycleOverloadDeduplicateSelector() );
+        }
+
+        selectorList.addAll( Arrays.asList(
             new CreateOrUpdateSelector(),
             new SourceRhsSelector(),
             new FactoryParameterSelector(),
             new MostSpecificResultTypeSelector()
-        );
+        ) );
+        this.selectors = selectorList;
     }
 
     /**

diff --git a/processor/src/main/java/org/mapstruct/ap/internal/option/Options.java b/processor/src/main/java/org/mapstruct/ap/internal/option/Options.java
@@ -26,6 +26,7 @@ public class Options {
     private final boolean verbose;
     private final NullValueMappingStrategyGem nullValueIterableMappingStrategy;
     private final NullValueMappingStrategyGem nullValueMapMappingStrategy;
+    private final boolean disableLifecycleOverloadDeduplicateSelector;
 
     //CHECKSTYLE:OFF
     public Options(boolean suppressGeneratorTimestamp, boolean suppressGeneratorVersionComment,
@@ -36,7 +37,8 @@ public Options(boolean suppressGeneratorTimestamp, boolean suppressGeneratorVers
                    boolean disableBuilders,
                    boolean verbose,
                    NullValueMappingStrategyGem nullValueIterableMappingStrategy,
-                   NullValueMappingStrategyGem nullValueMapMappingStrategy
+                   NullValueMappingStrategyGem nullValueMapMappingStrategy,
+                   boolean disableLifecycleOverloadDeduplicateSelector
                    ) {
         //CHECKSTYLE:ON
         this.suppressGeneratorTimestamp = suppressGeneratorTimestamp;
@@ -50,6 +52,7 @@ public Options(boolean suppressGeneratorTimestamp, boolean suppressGeneratorVers
         this.verbose = verbose;
         this.nullValueIterableMappingStrategy = nullValueIterableMappingStrategy;
         this.nullValueMapMappingStrategy = nullValueMapMappingStrategy;
+        this.disableLifecycleOverloadDeduplicateSelector = disableLifecycleOverloadDeduplicateSelector;
     }
 
     public boolean isSuppressGeneratorTimestamp() {
@@ -95,4 +98,8 @@ public NullValueMappingStrategyGem getNullValueIterableMappingStrategy() {
     public NullValueMappingStrategyGem getNullValueMapMappingStrategy() {
         return nullValueMapMappingStrategy;
     }
+
+    public boolean isDisableLifecycleOverloadDeduplicateSelector() {
+        return disableLifecycleOverloadDeduplicateSelector;
+    }
 }
diff --git a/...essor/src/main/java/org/mapstruct/ap/internal/processor/creation/MappingResolverImpl.java b/...essor/src/main/java/org/mapstruct/ap/internal/processor/creation/MappingResolverImpl.java
@@ -116,7 +116,7 @@ public MappingResolverImpl(FormattingMessager messager, ElementUtils elementUtil
 
         this.conversions = new Conversions( typeFactory );
         this.builtInMethods = new BuiltInMappingMethods( typeFactory );
-        this.methodSelectors = new MethodSelectors( typeUtils, elementUtils, messager );
+        this.methodSelectors = new MethodSelectors( typeUtils, elementUtils, messager, null );
 
         this.verboseLogging = verboseLogging;
     }

diff --git a/processor/src/test/java/org/mapstruct/ap/test/bugs/_3849/Child.java b/processor/src/test/java/org/mapstruct/ap/test/bugs/_3849/Child.java
@@ -0,0 +1,12 @@
+/*
+ * 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._3849;
+
+public class Child extends Parent {
+    public Child() {
+        super();
+    }
+}
diff --git a/processor/src/test/java/org/mapstruct/ap/test/bugs/_3849/ChildDto.java b/processor/src/test/java/org/mapstruct/ap/test/bugs/_3849/ChildDto.java
@@ -0,0 +1,16 @@
+/*
+ * 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._3849;
+
+public class ChildDto extends ParentDto {
+    public ChildDto(String value) {
+        super( value );
+    }
+
+    public void setValue(String value) {
+        super.setValue( value );
+    }
+}
diff --git a/processor/src/test/java/org/mapstruct/ap/test/bugs/_3849/DeduplicateBySourceMapper.java b/processor/src/test/java/org/mapstruct/ap/test/bugs/_3849/DeduplicateBySourceMapper.java
@@ -0,0 +1,69 @@
+/*
+ * 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._3849;
+
+import java.util.ArrayList;
+import java.util.List;
+
+import org.mapstruct.AfterMapping;
+import org.mapstruct.BeforeMapping;
+import org.mapstruct.Context;
+import org.mapstruct.Mapper;
+import org.mapstruct.MappingTarget;
+import org.mapstruct.factory.Mappers;
+
+@Mapper
+public interface DeduplicateBySourceMapper {
+
+    DeduplicateBySourceMapper INSTANCE = Mappers.getMapper( DeduplicateBySourceMapper.class );
+    List<String> INVOKED_METHODS = new ArrayList<>();
+
+    ParentDto mapParent(Parent source, @Context MappingContext context);
+
+    ParentDto mapChild(Child source, @Context MappingContext context);
+
+    class MappingContext {
+        @BeforeMapping
+        void deduplicateBySourceForBefore(Parent source, @MappingTarget ParentDto target) {
+            INVOKED_METHODS.add( "beforeMappingParentSourceInOtherClass" );
+        }
+
+        @BeforeMapping
+        void deduplicateBySourceForBefore(Child sourceChild, @MappingTarget ParentDto target) {
+            INVOKED_METHODS.add( "beforeMappingChildSourceInOtherClass" );
+        }
+
+        @AfterMapping
+        void deduplicateBySource(Parent source, @MappingTarget ParentDto target) {
+            INVOKED_METHODS.add( "afterMappingParentSourceInOtherClass" );
+        }
+
+        @AfterMapping
+        void deduplicateBySource(Child sourceChild, @MappingTarget ParentDto target) {
+            INVOKED_METHODS.add( "afterMappingChildSourceInOtherClass" );
+        }
+    }
+
+    @BeforeMapping
+    default void deduplicateBySourceForBefore(Parent source, @MappingTarget ParentDto target) {
+        INVOKED_METHODS.add( "beforeMappingParentSource" );
+    }
+
+    @BeforeMapping
+    default void deduplicateBySourceForBefore(Child sourceChild, @MappingTarget ParentDto target) {
+        INVOKED_METHODS.add( "beforeMappingChildSource" );
+    }
+
+    @AfterMapping
+    default void deduplicateBySource(Parent source, @MappingTarget ParentDto target) {
+        INVOKED_METHODS.add( "afterMappingParentSource" );
+    }
+
+    @AfterMapping
+    default void deduplicateBySource(Child sourceChild, @MappingTarget ParentDto target) {
+        INVOKED_METHODS.add( "afterMappingChildSource" );
+    }
+}