Cannot map from a covariant (extends) generic type #2677
Description
- Is this an issue (and hence not a question)?
I am trying to use a covariant generic type (<? extends X>) in the mapping parameter and the result is
Internal error in the mapping processor: java.lang.NullPointerException
at org.mapstruct.ap.internal.util.workarounds.SpecificCompilerWorkarounds.replaceTypeElementIfNecessary(SpecificCompilerWorkarounds.java:99)
at org.mapstruct.ap.internal.util.Executables.getAllEnclosedExecutableElements(Executables.java:98)
at org.mapstruct.ap.internal.model.common.Type.getAllMethods(Type.java:665)
at org.mapstruct.ap.internal.model.common.Type.getPropertyReadAccessors(Type.java:517)
at org.mapstruct.ap.internal.model.beanmapping.SourceReference.push(SourceReference.java:423)
at org.mapstruct.ap.internal.model.BeanMappingMethod$Builder.applyTargetThisMapping(BeanMappingMethod.java:1207)
at org.mapstruct.ap.internal.model.BeanMappingMethod$Builder.build(BeanMappingMethod.java:268)
at org.mapstruct.ap.internal.processor.MapperCreationProcessor.getMappingMethods(MapperCreationProcessor.java:378)
at org.mapstruct.ap.internal.processor.MapperCreationProcessor.getMapper(MapperCreationProcessor.java:152)
at org.mapstruct.ap.internal.processor.MapperCreationProcessor.process(MapperCreationProcessor.java:123)
at org.mapstruct.ap.internal.processor.MapperCreationProcessor.process(MapperCreationProcessor.java:74)
at org.mapstruct.ap.MappingProcessor.process(MappingProcessor.java:338)
at org.mapstruct.ap.MappingProcessor.processMapperTypeElement(MappingProcessor.java:318)
at org.mapstruct.ap.MappingProcessor.processMapperElements(MappingProcessor.java:267)
at org.mapstruct.ap.MappingProcessor.process(MappingProcessor.java:166)
at jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment.callProcessor(JavacProcessingEnvironment.java:980)
at jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment.discoverAndRunProcs(JavacProcessingEnvironment.java:896)
at jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment$Round.run(JavacProcessingEnvironment.java:1222)
at jdk.compiler/com.sun.tools.javac.processing.JavacProcessingEnvironment.doProcessing(JavacProcessingEnvironment.java:1334)
at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.processAnnotations(JavaCompiler.java:1258)
at jdk.compiler/com.sun.tools.javac.main.JavaCompiler.compile(JavaCompiler.java:936)
at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.lambda$doCall$0(JavacTaskImpl.java:104)
at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.handleExceptions(JavacTaskImpl.java:147)
at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.doCall(JavacTaskImpl.java:100)
at jdk.compiler/com.sun.tools.javac.api.JavacTaskImpl.call(JavacTaskImpl.java:94)
at org.codehaus.plexus.compiler.javac.JavaxToolsCompiler.compileInProcess(JavaxToolsCompiler.java:126)
at org.codehaus.plexus.compiler.javac.JavacCompiler.performCompile(JavacCompiler.java:174)
at org.apache.maven.plugin.compiler.AbstractCompilerMojo.execute(AbstractCompilerMojo.java:1134)
at org.apache.maven.plugin.compiler.CompilerMojo.execute(CompilerMojo.java:187)
at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:137)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:210)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:156)
at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:148)
at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:117)
at org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call(MultiThreadedBuilder.java:190)
at org.apache.maven.lifecycle.internal.builder.multithreaded.MultiThreadedBuilder$1.call(MultiThreadedBuilder.java:186)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:515)
at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264)
at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128)
at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628)
at java.base/java.lang.Thread.run(Thread.java:834)
The simplified code that produces this is:
@Mapper
public interface GenericMapper {
@Mapping(target = ".", source = "value")
Output map(Wrapper<? extends Parent> in); // Internal error in the mapping processor
@Mapping(target = ".", source = "value")
Output mapFromParent(Wrapper<Parent> in); // works
@Mapping(target = ".", source = "value")
Output mapFromChild(Wrapper<Child> in); // works
}with classes
class Wrapper<T> {
private boolean status;
private T value;
public void setStatus(boolean status) { this.status = status; }
public void setValue(T value) { this.value = value; }
public boolean isStatus() { return status;}
public T getValue() { return value; }
}
class Parent {
private int id;
public int getId() { return id; }
public void setId(int id) { this.id = id; }
}
class Child extends Parent {
private String whatever;
public String getWhatever() { return whatever; }
public void setWhatever(String whatever) { this.whatever = whatever; }
}
class Output {
int id;
boolean status;
public int getId() { return id; }
public void setId(int id) { this.id = id; }
public boolean isStatus() { return status; }
public void setStatus(boolean status) { this.status = status; }
}Mapstruct: 1.4.2.Final
JDK: Amazon Coretto 11.0.4
Maven: 3.6.3
IntelliJ Idea: 2021.2.3 Ultimate