#2481 Report ignored source properties which are missing

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

@@ -98,6 +98,7 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
         private Map<String, Accessor> unprocessedConstructorProperties;
         private Map<String, Accessor> unprocessedTargetProperties;
         private Map<String, Accessor> unprocessedSourceProperties;
+        private Set<String> missingIgnoredSourceProperties;
         private Set<String> targetProperties;
         private final List<PropertyMapping> propertyMappings = new ArrayList<>();
         private final Set<Parameter> unprocessedSourceParameters = new HashSet<>();
@@ -248,9 +249,12 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
             }
 
             // get bean mapping (when specified as annotation )
+            this.missingIgnoredSourceProperties = new HashSet<>();
             if ( beanMapping != null ) {
                 for ( String ignoreUnmapped : beanMapping.getIgnoreUnmappedSourceProperties() ) {
-                    unprocessedSourceProperties.remove( ignoreUnmapped );
+                    if ( unprocessedSourceProperties.remove( ignoreUnmapped ) == null ) {
+                        missingIgnoredSourceProperties.add( ignoreUnmapped );
+                    }
                 }
             }
 
@@ -283,6 +287,7 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
             // report errors on unmapped properties
             reportErrorForUnmappedTargetPropertiesIfRequired();
             reportErrorForUnmappedSourcePropertiesIfRequired();
+            reportErrorForMissingIgnoredSourceProperties();
 
             // mapNullToDefault
             boolean mapNullToDefault = method.getOptions()
@@ -1511,6 +1516,24 @@ public class BeanMappingMethod extends NormalTypeMappingMethod {
                 );
             }
         }
+
+        private void reportErrorForMissingIgnoredSourceProperties() {
+            if ( !missingIgnoredSourceProperties.isEmpty() ) {
+                Object[] args = new Object[] {
+                        MessageFormat.format(
+                                "{0,choice,1#property|1<properties}: \"{1}\"",
+                                missingIgnoredSourceProperties.size(),
+                                Strings.join( missingIgnoredSourceProperties, ", " )
+                        )
+                };
+
+                ctx.getMessager().printMessage(
+                    method.getExecutable(),
+                    Message.BEANMAPPING_MISSING_IGNORED_SOURCES_ERROR,
+                    args
+                );
+            }
+        }
     }
 
     private static class ConstructorAccessor {

processor/src/main/java/org/mapstruct/ap/internal/model/source/MapperOptions.java

@@ -85,7 +85,6 @@ public class MapperOptions extends DelegatingOptions {
     public ReportingPolicyGem unmappedTargetPolicy() {
         return mapper.unmappedTargetPolicy().hasValue() ?
             ReportingPolicyGem.valueOf( mapper.unmappedTargetPolicy().get() ) : next().unmappedTargetPolicy();
-
     }
 
     @Override

processor/src/main/java/org/mapstruct/ap/internal/util/Message.java

@@ -37,6 +37,7 @@ public enum Message {
     BEANMAPPING_UNMAPPED_FORGED_TARGETS_ERROR( "Unmapped target %s. Mapping from %s to %s." ),
     BEANMAPPING_UNMAPPED_SOURCES_WARNING( "Unmapped source %s.", Diagnostic.Kind.WARNING ),
     BEANMAPPING_UNMAPPED_SOURCES_ERROR( "Unmapped source %s." ),
+    BEANMAPPING_MISSING_IGNORED_SOURCES_ERROR( "Ignored unknown source %s." ),
     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." ),

processor/src/test/java/org/mapstruct/ap/test/missingignoredsource/ErroneousSourceTargetMapper.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.missingignoredsource;
+
+import org.mapstruct.BeanMapping;
+import org.mapstruct.Mapper;
+import org.mapstruct.ReportingPolicy;
+import org.mapstruct.factory.Mappers;
+
+@Mapper(
+    unmappedTargetPolicy = ReportingPolicy.IGNORE,
+    unmappedSourcePolicy = ReportingPolicy.IGNORE)
+public interface ErroneousSourceTargetMapper {
+    ErroneousSourceTargetMapper INSTANCE = Mappers.getMapper( ErroneousSourceTargetMapper.class );
+
+    @BeanMapping(ignoreUnmappedSourceProperties = "bar")
+    Object sourceToTarget(Object source);
+}

processor/src/test/java/org/mapstruct/ap/test/missingignoredsource/MissingIgnoredSourceTest.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.missingignoredsource;
+
+import javax.tools.Diagnostic.Kind;
+
+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;
+
+public class MissingIgnoredSourceTest {
+
+    @ProcessorTest
+    @WithClasses({ ErroneousSourceTargetMapper.class })
+    @ExpectedCompilationOutcome(
+        value = CompilationResult.FAILED,
+        diagnostics = {
+            @Diagnostic(type = ErroneousSourceTargetMapper.class,
+                kind = Kind.ERROR,
+                line = 20,
+                message = "Ignored unknown source property: \"bar\".")
+        }
+    )
+    public void shouldRaiseErrorDueToMissingIgnoredSourceProperty() {
+    }
+}