Implement review feedback

docs/extensions.adoc

@@ -1367,6 +1367,12 @@ Another problematic case is when the type is `final` or `sealed` as those are no
 To address these issues, Spock 2.4 introduces the `org.spockframework.runtime.extension.IDefaultValueProviderExtension` that is loaded via Java's `ServiceLoader` mechanism.
 This extension allows you to provide a default value if the `EmptyOrDummyResponse` doesn't have specific instructions for a type.
 
+.Example Implementation
+[source,groovy,indent=0]
+----
+include::{sourcedir-java}/smoke/mock/MaybeDefaultValueProvider.java[tag=sample-implementation]
+----
+
 It is primarily for framework developers who want to provide a default value for their framework types.
 Or users of a framework that doesn't provide default values for their special types.
 

docs/include.adoc

@@ -10,6 +10,10 @@
 :github-base: https://github.com/spockframework/spock
 :github-blob-base: {github-base}/blob
 :commit-ish: master
+// source java dir
+:base-sourcedir-java: spock-specs/src/test/java/org/spockframework
+:sourcedir-java: ../{base-sourcedir-java}
+:github-sourcedir-java: {github-blob-base}/{commit-ish}/{base-sourcedir-java}
 // source dir
 :base-sourcedir: spock-specs/src/test/groovy/org/spockframework/docs
 :sourcedir: ../{base-sourcedir}

docs/release_notes.adoc

@@ -13,6 +13,7 @@ include::include.adoc[]
 === Misc
 
 * Add `globalTimeout` to  `@Timeout` extension, to apply a timeout to all features in a specification, configurable via the spock configuration file spockPull:1986[]
+* Add new <<extensions.adoc#default-value-provider,`IDefaultValueProviderExtension`>> extension point to add support for special classes in the Stub's default `EmptyOrDummyResponse` spockPull:1994[]
 * Improve `@Timeout` extension will now use virtual threads if available spockPull:1986[]
 * Improve mock argument matching, types constraints or arguments in interactions can now handle primitive types like `_ as int` spockIssue:1974[]
 

spock-core/src/main/java/org/spockframework/mock/EmptyOrDummyResponse.java

@@ -44,6 +44,7 @@ private EmptyOrDummyResponse() {
     for (IDefaultValueProviderExtension provider : serviceLoader) {
       providers.add(provider);
     }
+    providers.sort(Comparator.comparing(p -> p.getClass().getName()));
     defaultValueProviders = Collections.unmodifiableList(providers);
   }
 

spock-core/src/main/java/org/spockframework/runtime/extension/IDefaultValueProviderExtension.java

@@ -41,6 +41,8 @@
 public interface IDefaultValueProviderExtension {
   /**
    * Provides a default value for the given type.
+   * <p>
+   * This method will be called for every `EmptyOrDummyResponse` non-default type, the returned values are not cached.
    *
    * @param type the type for which a default value should be provided, see {@link IMockMethod#getReturnType()}
    * @param exactType the exact type for which a default value should be provided, see {@link IMockMethod#getExactReturnType()}

spock-specs/src/test-java-ge-17/java/org/spockframework/smoke/mock/MaybeDefaultValueProvider.java → spock-specs/src/test/java/org/spockframework/smoke/mock/MaybeDefaultValueProvider.java

@@ -19,6 +19,7 @@
 import org.spockframework.runtime.extension.IDefaultValueProviderExtension;
 import org.spockframework.util.Nullable;
 
+// tag::sample-implementation[]
 public class MaybeDefaultValueProvider implements IDefaultValueProviderExtension {
   @Override
   public @Nullable Object provideDefaultValue(Class<?> type, Type exactType) {
@@ -28,3 +29,4 @@ public class MaybeDefaultValueProvider implements IDefaultValueProviderExtension
     return null;
   }
 }
+// end::sample-implementation[]