Properly decode $ref

fixes OpenAPITools#5720

modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java

@@ -43,6 +43,7 @@
 
 import java.math.BigDecimal;
 import java.net.URI;
+import java.net.URLDecoder;
 import java.util.*;
 import java.util.Map.Entry;
 import java.util.stream.Collectors;
@@ -71,7 +72,7 @@ public class ModelUtils {
         JSON_MAPPER = ObjectMapperFactory.createJson();
         YAML_MAPPER = ObjectMapperFactory.createYaml();
     }
-    
+
     public static void setDisallowAdditionalPropertiesIfNotPresent(boolean value) {
         GlobalSettings.setProperty(disallowAdditionalPropertiesIfNotPresent, Boolean.toString(value));
     }
@@ -386,7 +387,7 @@ public static String getSimpleRef(String ref) {
 
         }
 
-        return ref;
+        return URLDecoder.decode(ref);
     }
 
     /**
@@ -1077,15 +1078,15 @@ public static Schema unaliasSchema(OpenAPI openAPI,
 
     /**
      * Returns the additionalProperties Schema for the specified input schema.
-     * 
+     *
      * The additionalProperties keyword is used to control the handling of additional, undeclared
      * properties, that is, properties whose names are not listed in the properties keyword.
      * The additionalProperties keyword may be either a boolean or an object.
      * If additionalProperties is a boolean and set to false, no additional properties are allowed.
      * By default when the additionalProperties keyword is not specified in the input schema,
      * any additional properties are allowed. This is equivalent to setting additionalProperties
      * to the boolean value True or setting additionalProperties: {}
-     * 
+     *
      * @param openAPI the object that encapsulates the OAS document.
      * @param schema the input schema that may or may not have the additionalProperties keyword.
      * @return the Schema of the additionalProperties. The null value is returned if no additional
@@ -1141,7 +1142,7 @@ public static Schema getAdditionalProperties(OpenAPI openAPI, Schema schema) {
         }
         return null;
     }
-    
+
     public static Header getReferencedHeader(OpenAPI openAPI, Header header) {
         if (header != null && StringUtils.isNotEmpty(header.get$ref())) {
             String name = getSimpleRef(header.get$ref());
@@ -1478,12 +1479,12 @@ private static ObjectMapper getRightMapper(String data) {
 
     /**
      * Parse and return a JsonNode representation of the input OAS document.
-     * 
+     *
      * @param location the URL of the OAS document.
      * @param auths the list of authorization values to access the remote URL.
-     * 
+     *
      * @throws java.lang.Exception if an error occurs while retrieving the OpenAPI document.
-     * 
+     *
      * @return A JsonNode representation of the input OAS document.
      */
     public static JsonNode readWithInfo(String location, List<AuthorizationValue> auths) throws Exception {
@@ -1511,14 +1512,14 @@ public static JsonNode readWithInfo(String location, List<AuthorizationValue> au
     /**
      * Parse the OAS document at the specified location, get the swagger or openapi version
      * as specified in the source document, and return the version.
-     * 
+     *
      * For OAS 2.0 documents, return the value of the 'swagger' attribute.
      * For OAS 3.x documents, return the value of the 'openapi' attribute.
-     * 
+     *
      * @param openAPI the object that encapsulates the OAS document.
      * @param location the URL of the OAS document.
      * @param auths the list of authorization values to access the remote URL.
-     * 
+     *
      * @return the version of the OpenAPI document.
      */
     public static SemVer getOpenApiVersion(OpenAPI openAPI, String location, List<AuthorizationValue> auths) {