GH-1250 - Register runtime hints for JSONPath internals for native image builds.

Our AOT support generates a JSON file containing application module metadata for runtime usage. That file is evaluated using JSONPath expressions and that evaluation triggers reflection inside the JSONPath library. We now register reflection hints allow the invocation of the constructors of the necessary types.

This can be removed as soon as json-path/JsonPath#1042 is fixed.

Author: odrotbohm

spring-modulith-runtime/src/main/java/org/springframework/modulith/runtime/autoconfigure/ApplicationModulesFileGeneratingProcessor.java

@@ -17,12 +17,15 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import org.springframework.aot.hint.MemberCategory;
 import org.springframework.beans.factory.aot.BeanFactoryInitializationAotContribution;
 import org.springframework.beans.factory.aot.BeanFactoryInitializationAotProcessor;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.modulith.core.util.ApplicationModulesExporter;
 import org.springframework.modulith.runtime.ApplicationModulesRuntime;
 
+import com.jayway.jsonpath.internal.function.PathFunctionFactory;
+
 /**
  * Renders the application module description JSON into a resource named
  * {@value ApplicationModulesExporter#DEFAULT_LOCATION}.
@@ -51,6 +54,22 @@ public BeanFactoryInitializationAotContribution processAheadOfTime(ConfigurableL
 
 			context.getRuntimeHints().resources().registerPattern(location);
 			context.getGeneratedFiles().addResourceFile(location, exporter.toJson());
+
+			// Register JSONPath internals as available for reflective construction to be able to read the generated files in
+			// a native image
+			//
+			// TODO: Remove once https://github.com/json-path/JsonPath/issues/1042 is fixed
+
+			var reflection = context.getRuntimeHints().reflection();
+			var classLoader = ApplicationModulesFileGeneratingProcessor.class.getClassLoader();
+
+			PathFunctionFactory.FUNCTIONS.values().forEach(it -> {
+
+				// Tweak name due to shading
+				var typeName = it.getName().replace("com.jayway.jsonpath", "org.springframework.modulith.runtime.jsonpath");
+
+				reflection.registerTypeIfPresent(classLoader, typeName, MemberCategory.INVOKE_PUBLIC_CONSTRUCTORS);
+			});
 		};
 	}
 }