Register model converters only if they are not registered already (otherwise replace them) - fix #647

Author: Valentina Bojan

springdoc-openapi-common/src/main/java/org/springdoc/core/converters/ModelConverterRegistrar.java

@@ -20,11 +20,13 @@
 
 package org.springdoc.core.converters;
 
-import java.util.List;
-
 import io.swagger.v3.core.converter.ModelConverter;
 import io.swagger.v3.core.converter.ModelConverters;
 
+import java.lang.reflect.Field;
+import java.util.List;
+import java.util.Optional;
+
 /**
  * Wrapper for model converters to only register converters once
  */
@@ -35,6 +37,39 @@ public class ModelConverterRegistrar {
 	 *                        registered in {@link ModelConverters} instance
 	 */
 	public ModelConverterRegistrar(List<ModelConverter> modelConverters) {
-		modelConverters.forEach(ModelConverters.getInstance()::addConverter);
+		for (ModelConverter modelConverter : modelConverters) {
+			Optional<ModelConverter> registeredConverterOptional = getRegisteredConverterSameAs(modelConverter);
+
+			if (!registeredConverterOptional.isPresent()) {
+				ModelConverters.getInstance().addConverter(modelConverter);
+			} else {
+				registeredConverterOptional.ifPresent(alreadyRegisteredModelConverter -> {
+					ModelConverters.getInstance().removeConverter(alreadyRegisteredModelConverter);
+					ModelConverters.getInstance().addConverter(modelConverter);
+				});
+			}
+		}
+	}
+
+	private Optional<ModelConverter> getRegisteredConverterSameAs(ModelConverter modelConverter) {
+		try {
+			Field convertersField = ModelConverters.class.getDeclaredField("converters");
+			ModelConverters modelConvertersInstance = ModelConverters.getInstance();
+			convertersField.setAccessible(true);
+			List<ModelConverter> modelConverters = (List<ModelConverter>) convertersField.get(modelConvertersInstance);
+			return modelConverters.stream()
+					.filter(registeredModelConverter -> isSameConverter(registeredModelConverter, modelConverter))
+					.findFirst();
+		} catch (NoSuchFieldException | IllegalAccessException exception) {
+			throw new RuntimeException(exception);
+		}
+	}
+
+	private boolean isSameConverter(ModelConverter modelConverter1, ModelConverter modelConverter2) {
+		// for now we are comparing using the converter types which may not be what we want
+		Class<? extends ModelConverter> modelConverter1Class = modelConverter1.getClass();
+		Class<? extends ModelConverter> modelConverter2Class = modelConverter2.getClass();
+
+		return modelConverter1Class.equals(modelConverter2Class);
 	}
 }

springdoc-openapi-data-rest/src/test/java/test/org/springdoc/api/AbstractSpringDocTest.java

@@ -22,10 +22,7 @@
 import java.nio.file.Files;
 import java.nio.file.Path;
 import java.nio.file.Paths;
-import java.util.List;
 
-import io.swagger.v3.core.converter.ModelConverter;
-import io.swagger.v3.core.converter.ModelConverters;
 import nonapi.io.github.classgraph.utils.FileUtils;
 import org.junit.jupiter.api.AfterAll;
 import org.junit.jupiter.api.Test;
@@ -57,8 +54,6 @@ public abstract class AbstractSpringDocTest {
 
 	public static String className;
 
-	private static List<ModelConverter> modelConverters;
-
 	@Autowired
 	protected MockMvc mockMvc;
 
@@ -75,16 +70,10 @@ public static String getContent(String fileName) throws Exception {
 
 	@AfterAll
 	public static void afterClass() {
-		modelConverters.forEach(ModelConverters.getInstance()::removeConverter);
 		System.clearProperty("spring.hateoas.use-hal-as-default-json-media-type");
 		getConfig().replaceWithClass(org.springframework.data.domain.Pageable.class, Pageable.class);
 	}
 
-	@Autowired
-	private void setModelConverters(List<ModelConverter> modelConverters) {
-		AbstractSpringDocTest.modelConverters = modelConverters;
-	}
-
 	@Test
 	public void testApp() throws Exception {
 		className = getClass().getSimpleName();