mapstruct · filiphr · Aug 24, 2025 · Jul 27, 2025 · Jul 27, 2025 · Aug 1, 2025
diff --git a/processor/src/main/java/org/mapstruct/ap/internal/model/BeanMappingMethod.java b/processor/src/main/java/org/mapstruct/ap/internal/model/BeanMappingMethod.java
@@ -114,6 +114,7 @@ public static class Builder extends AbstractMappingMethodBuilder<Builder, BeanMa
         private Map<String, Accessor> unprocessedTargetProperties;
         private Map<String, Accessor> unprocessedSourceProperties;
         private Set<String> missingIgnoredSourceProperties;
+        private Set<String> redundantIgnoredSourceProperties;
         private Set<String> targetProperties;
         private final List<PropertyMapping> propertyMappings = new ArrayList<>();
         private final Set<Parameter> unprocessedSourceParameters = new HashSet<>();
@@ -278,11 +279,23 @@ else if ( !method.isUpdateMethod() ) {
 
             // get bean mapping (when specified as annotation )
             this.missingIgnoredSourceProperties = new HashSet<>();
-            if ( beanMapping != null ) {
+            this.redundantIgnoredSourceProperties = new HashSet<>();
+            if ( beanMapping != null && !beanMapping.getIgnoreUnmappedSourceProperties().isEmpty() ) {
+                // Get source properties explicitly mapped using @Mapping annotations
+                Set<String> mappedSourceProperties = method.getOptions().getMappings().stream()
+                        .map( MappingOptions::getSourceName )
+                        .filter( Objects::nonNull )
+                        .collect( Collectors.toSet() );
+
                 for ( String ignoreUnmapped : beanMapping.getIgnoreUnmappedSourceProperties() ) {
+                    // Track missing ignored properties (i.e. not in source class)
                     if ( unprocessedSourceProperties.remove( ignoreUnmapped ) == null ) {
                         missingIgnoredSourceProperties.add( ignoreUnmapped );
                     }
+                    // Track redundant ignored properties (actually mapped despite being ignored)
+                    if ( mappedSourceProperties.contains( ignoreUnmapped ) ) {
+                        redundantIgnoredSourceProperties.add( ignoreUnmapped );
+                    }
                 }
             }
 
@@ -331,6 +344,7 @@ else if ( !method.isUpdateMethod() ) {
             }
             reportErrorForMissingIgnoredSourceProperties();
             reportErrorForUnusedSourceParameters();
+            reportErrorForRedundantIgnoredSourceProperties();
 
             // mapNullToDefault
             boolean mapNullToDefault = method.getOptions()
@@ -1898,6 +1912,34 @@ private void reportErrorForMissingIgnoredSourceProperties() {
             }
         }
 
+        private void reportErrorForRedundantIgnoredSourceProperties() {
+            if ( !redundantIgnoredSourceProperties.isEmpty() ) {
+                ReportingPolicyGem unmappedSourcePolicy = getUnmappedSourcePolicy();
+                if ( unmappedSourcePolicy == ReportingPolicyGem.IGNORE ) { //don't show warning
+                    return;
+                }
+
+                Message message = Message.BEANMAPPING_REDUNDANT_IGNORED_SOURCES_WARNING;
+                if ( unmappedSourcePolicy.getDiagnosticKind() == Diagnostic.Kind.ERROR ) {
+                    message = Message.BEANMAPPING_REDUNDANT_IGNORED_SOURCES_ERROR;
+                }
+
+                Object[] args = new Object[] {
+                        MessageFormat.format(
+                                "{0,choice,1#property|1<properties} \"{1}\" {0,choice,1#is|1<are}",
+                                redundantIgnoredSourceProperties.size(),
+                                Strings.join( redundantIgnoredSourceProperties, ", " )
+                        )
+                };
+
+                ctx.getMessager().printMessage(
+                        method.getExecutable(),
+                        message,
+                        args
+                );
+            }
+        }
+
         private void reportErrorForUnusedSourceParameters() {
             for ( Parameter sourceParameter : unprocessedSourceParameters ) {
                 Type parameterType = sourceParameter.getType();

diff --git a/processor/src/main/java/org/mapstruct/ap/internal/util/Message.java b/processor/src/main/java/org/mapstruct/ap/internal/util/Message.java
@@ -42,6 +42,8 @@ public enum Message {
     BEANMAPPING_UNMAPPED_FORGED_SOURCES_WARNING( "Unmapped source %s. Mapping from %s to %s.", Diagnostic.Kind.WARNING ),
     BEANMAPPING_UNMAPPED_FORGED_SOURCES_ERROR( "Unmapped source %s. Mapping from %s to %s." ),
     BEANMAPPING_MISSING_IGNORED_SOURCES_ERROR( "Ignored unknown source %s." ),
+    BEANMAPPING_REDUNDANT_IGNORED_SOURCES_ERROR( "Source %s mapped despite being listed in ignoreUnmappedSourceProperties." ),
+    BEANMAPPING_REDUNDANT_IGNORED_SOURCES_WARNING( "Source %s mapped despite being listed in ignoreUnmappedSourceProperties.", Diagnostic.Kind.WARNING  ),
     BEANMAPPING_CYCLE_BETWEEN_PROPERTIES( "Cycle(s) between properties given via dependsOn(): %s." ),
     BEANMAPPING_UNKNOWN_PROPERTY_IN_DEPENDS_ON( "\"%s\" is no property of the method return type." ),
     BEANMAPPING_IGNORE_BY_DEFAULT_WITH_MAPPING_TARGET_THIS( "Using @BeanMapping( ignoreByDefault = true ) with @Mapping( target = \".\", ... ) is not allowed. You'll need to explicitly ignore the target properties that should be ignored instead." ),

diff --git a/processor/src/test/java/org/mapstruct/ap/test/ignoreunmapped/IgnoredMappedPropertyTest.java b/processor/src/test/java/org/mapstruct/ap/test/ignoreunmapped/IgnoredMappedPropertyTest.java
@@ -0,0 +1,136 @@
+/*
+ * 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.ignoreunmapped;
+
+import org.mapstruct.ap.test.ignoreunmapped.mapper.UserMapper;
+import org.mapstruct.ap.test.ignoreunmapped.mapper.UserMapperWithWarnSourcePolicy;
+import org.mapstruct.ap.test.ignoreunmapped.mapper.UserMapperWithWarnPolicyInMapperConfig;
+import org.mapstruct.ap.test.ignoreunmapped.mapper.UserMapperWithWarnSourcePolicyInMapper;
+import org.mapstruct.ap.test.ignoreunmapped.mapper.UserMapperWithoutBeanMapping;
+import org.mapstruct.ap.test.ignoreunmapped.mapper.UserMapperWithIgnorePolicyInMapperConfig;
+import org.mapstruct.ap.test.ignoreunmapped.mapper.UserMapperWithIgnoreSourcePolicy;
+import org.mapstruct.ap.test.ignoreunmapped.mapper.erroneous.UserMapperWithErrorPolicyInMapperConfig;
+import org.mapstruct.ap.test.ignoreunmapped.mapper.erroneous.UserMapperWithErrorSourcePolicy;
+import org.mapstruct.ap.test.ignoreunmapped.mapper.erroneous.UserMapperWithErrorSourcePolicyInMapper;
+import org.mapstruct.ap.test.ignoreunmapped.mapper.erroneous.UserMapperWithMultiMapping;
+import org.mapstruct.ap.testutil.IssueKey;
+import org.mapstruct.ap.testutil.ProcessorTest;
+import org.mapstruct.ap.testutil.WithClasses;
+import org.mapstruct.ap.testutil.compilation.annotation.CompilationResult;
+import org.mapstruct.ap.testutil.compilation.annotation.Diagnostic;
+import org.mapstruct.ap.testutil.compilation.annotation.ExpectedCompilationOutcome;
+
+import javax.tools.Diagnostic.Kind;
+
+/**
+ * Verifies that mapped properties listed in ignoreUnmappedSourceProperties trigger a warning.
+ *
+ * @author Ritesh Chopade(codeswithritesh)
+ */
+@IssueKey("3837")
+@WithClasses({UserEntity.class, UserDto.class})
+public class IgnoredMappedPropertyTest {
+
+    @ProcessorTest
+    @WithClasses({
+            UserMapper.class,
+            UserMapperWithIgnoreSourcePolicy.class,
+            UserMapperWithoutBeanMapping.class,
+            UserMapperWithIgnorePolicyInMapperConfig.class
+    })
+    @ExpectedCompilationOutcome(
+            value = CompilationResult.SUCCEEDED
+    )
+    public void shouldNotWarnAboutRedundantIgnore() {
+    }
+
+    @ProcessorTest
+    @WithClasses({
+            UserMapperWithErrorSourcePolicy.class,
+            UserMapperWithErrorSourcePolicyInMapper.class,
+            UserMapperWithErrorPolicyInMapperConfig.class
+    })
+    @ExpectedCompilationOutcome(
+            value = CompilationResult.FAILED,
+            diagnostics = {
+                    @Diagnostic(
+                            type = UserMapperWithErrorSourcePolicy.class,
+                            kind = Kind.ERROR,
+                            line = 20,
+                            message = "Source property \"email\" is mapped despite being " +
+                                    "listed in ignoreUnmappedSourceProperties."
+                    ),
+                    @Diagnostic(
+                            type = UserMapperWithErrorSourcePolicyInMapper.class,
+                            kind = Kind.ERROR,
+                            line = 19,
+                            message = "Source property \"email\" is mapped despite being " +
+                                    "listed in ignoreUnmappedSourceProperties."
+                    ),
+                    @Diagnostic(
+                            type = UserMapperWithErrorPolicyInMapperConfig.class,
+                            kind = Kind.ERROR,
+                            line = 23,
+                            message = "Source property \"email\" is mapped despite being " +
+                                    "listed in ignoreUnmappedSourceProperties."
+                    )
+            }
+    )
+    public void shouldWarnAboutRedundantIgnoreWithErrorPolicy() {
+    }
+
+    @ProcessorTest
+    @WithClasses({
+            UserMapperWithWarnSourcePolicy.class,
+            UserMapperWithWarnSourcePolicyInMapper.class,
+            UserMapperWithWarnPolicyInMapperConfig.class
+    })
+    @ExpectedCompilationOutcome(
+            value = CompilationResult.SUCCEEDED,
+            diagnostics = {
+                    @Diagnostic(
+                            type = UserMapperWithWarnSourcePolicy.class,
+                            kind = Kind.WARNING,
+                            line = 20,
+                            message = "Source property \"email\" is mapped despite being " +
+                                    "listed in ignoreUnmappedSourceProperties."
+                    ),
+                    @Diagnostic(
+                            type = UserMapperWithWarnSourcePolicyInMapper.class,
+                            kind = Kind.WARNING,
+                            line = 19,
+                            message = "Source property \"email\" is mapped despite being " +
+                                    "listed in ignoreUnmappedSourceProperties."
+                    ),
+                    @Diagnostic(
+                            type = UserMapperWithWarnPolicyInMapperConfig.class,
+                            kind = Kind.WARNING,
+                            line = 23,
+                            message = "Source property \"email\" is mapped despite being " +
+                                    "listed in ignoreUnmappedSourceProperties."
+                    )
+            }
+    )
+    public void shouldWarnAboutRedundantIgnoreWithWarnPolicy() {
+    }
+
+    @ProcessorTest
+    @WithClasses({UserMapperWithMultiMapping.class})
+    @ExpectedCompilationOutcome(
+            value = CompilationResult.FAILED,
+            diagnostics = {
+                    @Diagnostic(
+                            type = UserMapperWithMultiMapping.class,
+                            kind = Kind.ERROR,
+                            line = 21,
+                            message = "Source properties \"email, username\" are mapped despite " +
+                                    "being listed in ignoreUnmappedSourceProperties."
+                    )
+            }
+    )
+    public void shouldWarnAboutRedundantIgnoreWithMultiMapping() {
+    }
+}
diff --git a/processor/src/test/java/org/mapstruct/ap/test/ignoreunmapped/UserDto.java b/processor/src/test/java/org/mapstruct/ap/test/ignoreunmapped/UserDto.java
@@ -0,0 +1,31 @@
+/*
+ * 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.ignoreunmapped;
+
+/**
+ * @author Ritesh Chopade(codeswithritesh)
+ */
+public class UserDto {
+
+    private String username;
+    private String email;
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+}
diff --git a/processor/src/test/java/org/mapstruct/ap/test/ignoreunmapped/UserEntity.java b/processor/src/test/java/org/mapstruct/ap/test/ignoreunmapped/UserEntity.java
@@ -0,0 +1,40 @@
+/*
+ * 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.ignoreunmapped;
+
+/**
+ * @author Ritesh Chopade(codeswithritesh)
+ */
+public class UserEntity {
+
+    private String username;
+    private String email;
+    private String password;
+
+    public String getUsername() {
+        return username;
+    }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getEmail() {
+        return email;
+    }
+
+    public void setEmail(String email) {
+        this.email = email;
+    }
+
+    public String getPassword() {
+        return password;
+    }
+
+    public void setPassword(String password) {
+        this.password = password;
+    }
+}
diff --git a/processor/src/test/java/org/mapstruct/ap/test/ignoreunmapped/mapper/UserMapper.java b/processor/src/test/java/org/mapstruct/ap/test/ignoreunmapped/mapper/UserMapper.java
@@ -0,0 +1,19 @@
+/*
+ * 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.ignoreunmapped.mapper;
+
+import org.mapstruct.BeanMapping;
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.ap.test.ignoreunmapped.UserDto;
+import org.mapstruct.ap.test.ignoreunmapped.UserEntity;
+
+@Mapper
+public interface UserMapper {
+    @BeanMapping(ignoreUnmappedSourceProperties = {"password", "email"})
+    @Mapping(source = "email", target = "email")
+    UserDto map(UserEntity user);
+}
diff --git a/...org/mapstruct/ap/test/ignoreunmapped/mapper/UserMapperWithIgnorePolicyInMapperConfig.java b/...org/mapstruct/ap/test/ignoreunmapped/mapper/UserMapperWithIgnorePolicyInMapperConfig.java
@@ -0,0 +1,24 @@
+/*
+ * 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.ignoreunmapped.mapper;
+
+import org.mapstruct.BeanMapping;
+import org.mapstruct.Mapper;
+import org.mapstruct.MapperConfig;
+import org.mapstruct.Mapping;
+import org.mapstruct.ReportingPolicy;
+import org.mapstruct.ap.test.ignoreunmapped.UserDto;
+import org.mapstruct.ap.test.ignoreunmapped.UserEntity;
+
+@MapperConfig(unmappedSourcePolicy = ReportingPolicy.IGNORE)
+interface IgnorePolicyConfig { }
+
+@Mapper(config = IgnorePolicyConfig.class)
+public interface UserMapperWithIgnorePolicyInMapperConfig {
+    @BeanMapping(ignoreUnmappedSourceProperties = {"password", "email"})
+    @Mapping(source = "email", target = "email")
+    UserDto map(UserEntity user);
+}
diff --git a/...st/java/org/mapstruct/ap/test/ignoreunmapped/mapper/UserMapperWithIgnoreSourcePolicy.java b/...st/java/org/mapstruct/ap/test/ignoreunmapped/mapper/UserMapperWithIgnoreSourcePolicy.java
@@ -0,0 +1,21 @@
+/*
+ * 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.ignoreunmapped.mapper;
+
+import org.mapstruct.BeanMapping;
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.ReportingPolicy;
+import org.mapstruct.ap.test.ignoreunmapped.UserDto;
+import org.mapstruct.ap.test.ignoreunmapped.UserEntity;
+
+@Mapper
+public interface UserMapperWithIgnoreSourcePolicy {
+
+    @BeanMapping(ignoreUnmappedSourceProperties = {"password", "email"}, unmappedSourcePolicy = ReportingPolicy.IGNORE)
+    @Mapping(source = "email", target = "email")
+    UserDto map(UserEntity user);
+}
diff --git a/...a/org/mapstruct/ap/test/ignoreunmapped/mapper/UserMapperWithWarnPolicyInMapperConfig.java b/...a/org/mapstruct/ap/test/ignoreunmapped/mapper/UserMapperWithWarnPolicyInMapperConfig.java
@@ -0,0 +1,24 @@
+/*
+ * 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.ignoreunmapped.mapper;
+
+import org.mapstruct.BeanMapping;
+import org.mapstruct.Mapper;
+import org.mapstruct.MapperConfig;
+import org.mapstruct.Mapping;
+import org.mapstruct.ReportingPolicy;
+import org.mapstruct.ap.test.ignoreunmapped.UserDto;
+import org.mapstruct.ap.test.ignoreunmapped.UserEntity;
+
+@MapperConfig(unmappedSourcePolicy = ReportingPolicy.WARN)
+interface WarnPolicyConfig { }
+
+@Mapper(config = WarnPolicyConfig.class)
+public interface UserMapperWithWarnPolicyInMapperConfig {
+    @BeanMapping(ignoreUnmappedSourceProperties = {"password", "email"})
+    @Mapping(source = "email", target = "email")
+    UserDto map(UserEntity user);
+}