Build fails with OpenAPI and Optional QueryParam

[seseso]

Describe the bug
Using OpenAPI extension, project fails to build if a resource is defined with an Optional QueryParam. Ex.
@GET @Produces(MediaType.TEXT_PLAIN) public String helloName(@QueryParam("name") Optional<String> name) { return "hello " + name.orElse("Quarkus!"); }
The exception is:
Failed to execute goal io.quarkus:quarkus-maven-plugin:1.0.0.CR1:build (default) on project code-with-quarkus: Failed to build a runnable JAR: Failed to augment application classes: Build failure: Build failed due to errors
[error]: Build step io.quarkus.smallrye.openapi.deployment.SmallRyeOpenApiProcessor#build threw an exception: java.lang.StringIndexOutOfBoundsException: String index out of range: 3
at java.lang.String.charAt(String.java:658)
at io.smallrye.openapi.runtime.scanner.dataobject.TypeResolver.updateTypeResolvers(TypeResolver.java:456)
at io.smallrye.openapi.runtime.scanner.dataobject.TypeResolver.scanMethod(TypeResolver.java:426)
at io.smallrye.openapi.runtime.scanner.dataobject.TypeResolver.lambda$getAllFields$4(TypeResolver.java:355)
at java.util.stream.ForEachOps$ForEachOp$OfRef.accept(ForEachOps.java:184)
at java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:175)
at java.util.Iterator.forEachRemaining(Iterator.java:116)
at java.util.Spliterators$IteratorSpliterator.forEachRemaining(Spliterators.java:1801)
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482)
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472)
at java.util.stream.ForEachOps$ForEachOp.evaluateSequential(ForEachOps.java:151)
at java.util.stream.ForEachOps$ForEachOp$OfRef.evaluateSequential(ForEachOps.java:174)
at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.util.stream.ReferencePipeline.forEach(ReferencePipeline.java:418)
at io.smallrye.openapi.runtime.scanner.dataobject.TypeResolver.getAllFields(TypeResolver.java:355)
at io.smallrye.openapi.runtime.scanner.OpenApiDataObjectScanner.depthFirstGraphSearch(OpenApiDataObjectScanner.java:247)
at io.smallrye.openapi.runtime.scanner.OpenApiDataObjectScanner.process(OpenApiDataObjectScanner.java:221)
at io.smallrye.openapi.runtime.scanner.OpenApiDataObjectScanner.process(OpenApiDataObjectScanner.java:168)
at io.smallrye.openapi.runtime.util.SchemaFactory.typeToSchema(SchemaFactory.java:240)
at io.smallrye.openapi.runtime.scanner.ParameterProcessor.getParameters(ParameterProcessor.java:522)
at io.smallrye.openapi.runtime.scanner.ParameterProcessor.process(ParameterProcessor.java:382)
at io.smallrye.openapi.runtime.scanner.OpenApiAnnotationScanner.processJaxRsMethod(OpenApiAnnotationScanner.java:584)
at io.smallrye.openapi.runtime.scanner.OpenApiAnnotationScanner.processJaxRsResourceClass(OpenApiAnnotationScanner.java:437)
at io.smallrye.openapi.runtime.scanner.OpenApiAnnotationScanner.scan(OpenApiAnnotationScanner.java:214)
at io.quarkus.smallrye.openapi.deployment.SmallRyeOpenApiProcessor.generateAnnotationModel(SmallRyeOpenApiProcessor.java:298)
at io.quarkus.smallrye.openapi.deployment.SmallRyeOpenApiProcessor.build(SmallRyeOpenApiProcessor.java:246)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at io.quarkus.deployment.ExtensionLoader$1.execute(ExtensionLoader.java:941)
at io.quarkus.builder.BuildContext.run(BuildContext.java:415)
at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35)
at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:2011)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1535)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1426)
at java.lang.Thread.run(Thread.java:748)
at org.jboss.threads.JBossThread.run(JBossThread.java:479)

Expected behavior
Should compile (and work) as RestEasy does

Actual behavior
Compile error

To Reproduce
Steps to reproduce the behavior:

1. Create a project wirh RestEasy and OpenAPI
2. Create an endpoint resource with a @QueryParam Optional (Ex. @QueryParam("name") Optional name)
3. Compile the project and see the exception

Configuration

# N/A

Screenshots
N/A

Environment (please complete the following information):

• Output of uname -a or ver: Windows 10 PRO
• Output of java -version: OpenJDK 8
• GraalVM version (if different from Java): N/A
• Quarkus version or git rev: 1.0.0.CR1

Additional context
N/A

[machi1990]

This looks like a bug in smallrye-openapi happens when we try to deduce the schema from the Optional type. Shouldn't the schema be deduced from the wrapped type in this case? I am also unsure that should be handled at the spec level.
/cc @kenfinnigan maybe you could have better insight?

@seseso To work around the issue, you can add the schema as below

@GET 
@Produces(MediaType.TEXT_PLAIN) 
public String helloName(@QueryParam("name") @Parameter(schema = @Schema(implementation = String.class)) Optional<String> name) { 
    return "hello " + name.orElse("Quarkus!"); 
}

[kenfinnigan]

@EricWittmann ^^

[EricWittmann]

I've opened: smallrye/smallrye-open-api#210

[machi1990]

Thanks @EricWittmann @kenfinnigan