#2139 reproducer (#2140)

* #2139 reproducer

* #2139 solution

* #2139 license

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

@@ -238,10 +238,10 @@ public class MappingMethodOptions {
     }
 
     private boolean elementsAreContainedIn( String redefinedName, String inheritedName ) {
-        if ( redefinedName.startsWith( inheritedName ) ) {
+        if ( inheritedName != null && redefinedName.startsWith( inheritedName ) ) {
             // it is possible to redefine an exact matching source name, because the same source can be mapped to
             // multiple targets. It is not possible for target, but caught by the Set and equals methoded in
-            // MappingOptions
+            // MappingOptions. SourceName == null also could hint at redefinition
             if ( redefinedName.length() > inheritedName.length() ) {
                 // redefined.lenght() > inherited.length(), first following character should be separator
                 return '.' == redefinedName.charAt( inheritedName.length() );

processor/src/test/java/org/mapstruct/ap/test/bugs/_2101/Issue2101Test.java

@@ -64,4 +64,20 @@ public class Issue2101Test {
         assertThat( target.value3 ).isEqualTo( "test" );
 
     }
+
+    @Test
+    @WithClasses(Issue2102IgnoreAllButMapper.class)
+    public void shouldApplyIgnoreAllButTemplateOfMethod1() {
+
+        Issue2102IgnoreAllButMapper.Source source = new Issue2102IgnoreAllButMapper.Source();
+        source.value1 = "value1";
+        source.value2 = "value2";
+
+        Issue2102IgnoreAllButMapper.Target target = Issue2102IgnoreAllButMapper.INSTANCE.map1( source );
+        assertThat( target.value1 ).isEqualTo( "value1" );
+
+        target = Issue2102IgnoreAllButMapper.INSTANCE.map2( source );
+        assertThat( target.value1 ).isEqualTo( "value2" );
+
+    }
 }

processor/src/test/java/org/mapstruct/ap/test/bugs/_2101/Issue2102IgnoreAllButMapper.java

@@ -0,0 +1,38 @@
+/*
+ * 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._2101;
+
+import org.mapstruct.BeanMapping;
+import org.mapstruct.InheritConfiguration;
+import org.mapstruct.Mapper;
+import org.mapstruct.Mapping;
+import org.mapstruct.factory.Mappers;
+
+@Mapper
+public interface Issue2102IgnoreAllButMapper {
+
+    Issue2102IgnoreAllButMapper INSTANCE = Mappers.getMapper( Issue2102IgnoreAllButMapper.class );
+
+    @BeanMapping( ignoreByDefault = true )
+    @Mapping(target = "value1") // but do map value1
+    Target map1(Source source);
+
+    @InheritConfiguration
+    @Mapping(target = "value1", source = "value2" )
+    Target map2(Source source);
+
+    //CHECKSTYLE:OFF
+    class Source {
+        public String value1;
+        public String value2;
+    }
+
+    class Target {
+        public String value1;
+    }
+    //CHECKSTYLE:ON
+
+}