External conversions mapper methods are not generated in adapter class

[myatmin]

Environment

• Mapstruct: 1.5.2.Final
• Mapstruct Sprint Extension: 0.1.2
• Compiler: Eclipse JDT (IDE) 1.4.100.v20220318-0906
• Java Language Server - Java: 17.0.4 (Microsoft)
• Source/Target - Java: 11.0.15 (Temurin)
• IDE: VSCode

Configuration Code

@MapperConfig(componentModel = "spring")
@SpringMapperConfig(
    externalConversions = @ExternalConversion(sourceType = String.class, targetType = Locale.class))
public interface MapstructConfig {}

Log Output

!ENTRY org.eclipse.jdt.apt.pluggable.core 4 1 2022-08-30 02:26:34.062
!MESSAGE Exception thrown by Java annotation processor org.mapstruct.extensions.spring.converter.ConverterMapperProcessor@2c971632
!STACK 0
java.lang.Exception: java.lang.ClassCastException: class org.eclipse.jdt.internal.compiler.apt.model.AnnotationValueImpl cannot be cast to class javax.lang.model.element.AnnotationMirror (org.eclipse.jdt.internal.compiler.apt.model.AnnotationValueImpl is in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @61817efb; javax.lang.model.element.AnnotationMirror is in module java.compiler of loader 'platform')
	at org.eclipse.jdt.internal.compiler.apt.dispatch.RoundDispatcher.handleProcessor(RoundDispatcher.java:172)
	at org.eclipse.jdt.internal.compiler.apt.dispatch.RoundDispatcher.round(RoundDispatcher.java:124)
	at org.eclipse.jdt.internal.compiler.apt.dispatch.BaseAnnotationProcessorManager.processAnnotations(BaseAnnotationProcessorManager.java:172)
	at org.eclipse.jdt.internal.apt.pluggable.core.dispatch.IdeAnnotationProcessorManager.processAnnotations(IdeAnnotationProcessorManager.java:138)
	at org.eclipse.jdt.internal.compiler.Compiler.processAnnotations(Compiler.java:953)
	at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:450)
	at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:426)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:379)
	at org.eclipse.jdt.internal.core.builder.IncrementalImageBuilder.compile(IncrementalImageBuilder.java:371)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:311)
	at org.eclipse.jdt.internal.core.builder.IncrementalImageBuilder.incrementalBuildLoop(IncrementalImageBuilder.java:190)
	at org.eclipse.jdt.internal.core.builder.IncrementalImageBuilder.build(IncrementalImageBuilder.java:147)
	at org.eclipse.jdt.internal.core.builder.JavaBuilder.buildDeltas(JavaBuilder.java:290)
	at org.eclipse.jdt.internal.core.builder.JavaBuilder.build(JavaBuilder.java:213)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:1024)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:254)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:311)
	at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:400)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:403)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:514)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:462)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:544)
	at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:161)
	at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:255)
	at org.eclipse.core.internal.jobs.Worker.run(Worker.java:63)
Caused by: java.lang.ClassCastException: class org.eclipse.jdt.internal.compiler.apt.model.AnnotationValueImpl cannot be cast to class javax.lang.model.element.AnnotationMirror (org.eclipse.jdt.internal.compiler.apt.model.AnnotationValueImpl is in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @61817efb; javax.lang.model.element.AnnotationMirror is in module java.compiler of loader 'platform')
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
	at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(ArrayList.java:1625)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921)
	at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
	at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682)
	at org.mapstruct.extensions.spring.converter.ConverterMapperProcessor.toSourceTargetTypeNamePairs(ConverterMapperProcessor.java:104)
	at java.base/java.util.Optional.map(Optional.java:260)
	at org.mapstruct.extensions.spring.converter.ConverterMapperProcessor.getExternalConversionMappings(ConverterMapperProcessor.java:95)
	at org.mapstruct.extensions.spring.converter.ConverterMapperProcessor.buildDescriptor(ConverterMapperProcessor.java:77)
	at org.mapstruct.extensions.spring.converter.ConverterMapperProcessor.process(ConverterMapperProcessor.java:63)
	at org.eclipse.jdt.internal.compiler.apt.dispatch.RoundDispatcher.handleProcessor(RoundDispatcher.java:142)
	... 26 more

[Chessray]

Sorry, I'm struggling with replicating this. Could you please provide a minimum example project? In theory, it should be sufficient to start with the external conversions example and modify this until you reach the error.

[myatmin]

Just realized that mvn compile generated the adapter class correctly. But build project from VSCode is not.
Here is the sample project with VSCode devcontainer. mapstruct-example.zip

Tried with both Java 11 and 17 compiler target but results are still the same.

[Chessray]

Sorry, I don't use VS Code regularly. I downloaded it now and imported and ran your example project without any issues. So this looks like a local config issue. I'm not closing the issue for now as someone else might have more insights into what could be going on.

[myatmin]

With following environment compiler: Eclipse JDT (IDE) 1.4.200.v20220802-0458, environment: Java 17.0.4.1 (Eclipse Adoptium), adapter class will NOT be generating method for all of the converters, but it only generate the class.

[Error - 4:53:17 AM] Sep 30, 2022, 4:53:17 AM Exception thrown by Java annotation processor org.mapstruct.extensions.spring.converter.ConverterMapperProcessor@67b39ba
java.lang.ClassCastException: class org.eclipse.jdt.internal.compiler.apt.model.AnnotationValueImpl cannot be cast to class javax.lang.model.element.AnnotationMirror (org.eclipse.jdt.internal.compiler.apt.model.AnnotationValueImpl is in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @6f270916; javax.lang.model.element.AnnotationMirror is in module java.compiler of loader 'platform')
java.lang.Exception: java.lang.ClassCastException: class org.eclipse.jdt.internal.compiler.apt.model.AnnotationValueImpl cannot be cast to class javax.lang.model.element.AnnotationMirror (org.eclipse.jdt.internal.compiler.apt.model.AnnotationValueImpl is in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @6f270916; javax.lang.model.element.AnnotationMirror is in module java.compiler of loader 'platform')
	at org.eclipse.jdt.internal.compiler.apt.dispatch.RoundDispatcher.handleProcessor(RoundDispatcher.java:172)
	at org.eclipse.jdt.internal.compiler.apt.dispatch.RoundDispatcher.round(RoundDispatcher.java:124)
	at org.eclipse.jdt.internal.compiler.apt.dispatch.BaseAnnotationProcessorManager.processAnnotations(BaseAnnotationProcessorManager.java:172)
	at org.eclipse.jdt.internal.apt.pluggable.core.dispatch.IdeAnnotationProcessorManager.processAnnotations(IdeAnnotationProcessorManager.java:138)
	at org.eclipse.jdt.internal.compiler.Compiler.processAnnotations(Compiler.java:953)
	at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:450)
	at org.eclipse.jdt.internal.compiler.Compiler.compile(Compiler.java:426)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:379)
	at org.eclipse.jdt.internal.core.builder.BatchImageBuilder.compile(BatchImageBuilder.java:214)
	at org.eclipse.jdt.internal.core.builder.AbstractImageBuilder.compile(AbstractImageBuilder.java:311)
	at org.eclipse.jdt.internal.core.builder.BatchImageBuilder.build(BatchImageBuilder.java:79)
	at org.eclipse.jdt.internal.core.builder.JavaBuilder.buildAll(JavaBuilder.java:273)
	at org.eclipse.jdt.internal.core.builder.JavaBuilder.build(JavaBuilder.java:188)
	at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:1024)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:254)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:311)
	at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:400)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:403)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:514)
	at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:462)
	at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:544)
	at org.eclipse.core.internal.resources.Workspace.buildInternal(Workspace.java:524)
	at org.eclipse.core.internal.resources.Workspace.build(Workspace.java:420)
	at org.eclipse.jdt.ls.core.internal.handlers.BuildWorkspaceHandler.buildProjects(BuildWorkspaceHandler.java:112)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$28(JDTLanguageServer.java:885)
	at org.eclipse.jdt.ls.core.internal.handlers.JDTLanguageServer.lambda$55(JDTLanguageServer.java:1070)
	at java.base/java.util.concurrent.CompletableFuture$UniApply.tryFire(Unknown Source)
	at java.base/java.util.concurrent.CompletableFuture$Completion.exec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinTask.doExec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool$WorkQueue.topLevelExec(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool.scan(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinPool.runWorker(Unknown Source)
	at java.base/java.util.concurrent.ForkJoinWorkerThread.run(Unknown Source)
Caused by: java.lang.ClassCastException: class org.eclipse.jdt.internal.compiler.apt.model.AnnotationValueImpl cannot be cast to class javax.lang.model.element.AnnotationMirror (org.eclipse.jdt.internal.compiler.apt.model.AnnotationValueImpl is in unnamed module of loader org.eclipse.osgi.internal.loader.EquinoxClassLoader @6f270916; javax.lang.model.element.AnnotationMirror is in module java.compiler of loader 'platform')
	at java.base/java.util.stream.ReferencePipeline$3$1.accept(Unknown Source)
	at java.base/java.util.ArrayList$ArrayListSpliterator.forEachRemaining(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.copyInto(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(Unknown Source)
	at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(Unknown Source)
	at java.base/java.util.stream.AbstractPipeline.evaluate(Unknown Source)
	at java.base/java.util.stream.ReferencePipeline.collect(Unknown Source)
	at org.mapstruct.extensions.spring.converter.ConverterMapperProcessor.toSourceTargetTypeNamePairs(ConverterMapperProcessor.java:104)
	at java.base/java.util.Optional.map(Unknown Source)
	at org.mapstruct.extensions.spring.converter.ConverterMapperProcessor.getExternalConversionMappings(ConverterMapperProcessor.java:95)
	at org.mapstruct.extensions.spring.converter.ConverterMapperProcessor.buildDescriptor(ConverterMapperProcessor.java:77)
	at org.mapstruct.extensions.spring.converter.ConverterMapperProcessor.process(ConverterMapperProcessor.java:63)
	at org.eclipse.jdt.internal.compiler.apt.dispatch.RoundDispatcher.handleProcessor(RoundDispatcher.java:142)
	... 34 more

[myatmin]

Adapter method will not be generated for below converter even though mapstruct able generate the implementation class.

@Mapper(config = MapperConfiguration.class)
interface MyConverter extends Converter<Foo, FooDto> {
}

To be able to generate the method for adapter class, have to declare convert method again as below.

@Mapper(config = MapperConfiguration.class)
interface MyConverter extends Converter<Foo, FooDto> {
   FooDto convert(Foo source);
}