Cannot override servers in api-docs.yaml using OpenApiCustomiser; Fixes #1188.

Author: bnasslahsen

springdoc-openapi-common/src/main/java/org/springdoc/core/OpenAPIService.java

@@ -477,6 +477,8 @@ private List<Server> resolveProperties(List<Server> servers) {
 		servers.forEach(server -> {
 			resolveProperty(server::getUrl, server::url, propertyResolverUtils);
 			resolveProperty(server::getDescription, server::description, propertyResolverUtils);
+			if(CollectionUtils.isEmpty(server.getVariables()))
+				server.setVariables(null);
 		});
 		return servers;
 	}

springdoc-openapi-webmvc-core/src/test/resources/results/app137.json

@@ -8,8 +8,7 @@
   "servers": [
     {
       "url": "http://test.toto.com",
-      "description": "toto desc",
-      "variables": {}
+      "description": "toto desc"
     }
   ],
   "paths": {