Admin-client compatibility with the future Keycloak server versions

closes #94

Signed-off-by: mposolda <mposolda@gmail.com>

README.md

@@ -16,7 +16,11 @@ and hence are supposed to be updated there (whenever needed) and synced into thi
 
 ## Syncing the files from Keycloak repository
 
-* Checkout [main Keycloak server repository](https://github.com/keycloak/keycloak) and build it on your laptop to make sure latest Keycloak stuff available in your local maven repository.
+* Fetch [main Keycloak server repository](https://github.com/keycloak/keycloak) and checkout the last `release/X.Y` branch (For example `git checkout release/26.0` ). Note that we usually
+cannot sync from the server `main` branch as it is under development and there is still a chance that some things being developed here would be later updated/removed.
+Which could be an issue as for client, we want to preserve backwards compatibility.
+
+* build it on your laptop to make sure latest Keycloak stuff available in your local maven repository.
 
 * Run [sync-keycloak-sources.sh](.github/scripts/sync-keycloak-sources.sh)
 

admin-client/src/main/java/org/keycloak/admin/client/JacksonProvider.java

@@ -1,5 +1,6 @@
 package org.keycloak.admin.client;
 
+import com.fasterxml.jackson.databind.DeserializationFeature;
 import jakarta.ws.rs.core.MediaType;
 
 import com.fasterxml.jackson.annotation.JsonInclude;
@@ -14,6 +15,9 @@ public ObjectMapper locateMapper(Class<?> type, MediaType mediaType) {
 
         // Same like JSONSerialization class. Makes it possible to use admin-client against older versions of Keycloak server where the properties on representations might be different
         objectMapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
+
+        // The client must work with the newer versions of Keycloak server, which might contain the JSON fields not yet known by the client. So unknown fields will be ignored.
+        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
 
         return objectMapper;
     }

testsuite/framework/src/main/java/org/keycloak/testsuite/util/AdminClientUtil.java

@@ -29,6 +29,7 @@
 import org.jboss.resteasy.client.jaxrs.engines.ClientHttpEngineBuilder43;
 import org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider;
 import org.keycloak.OAuth2Constants;
+import org.keycloak.admin.client.JacksonProvider;
 import org.keycloak.admin.client.Keycloak;
 import org.keycloak.admin.client.KeycloakBuilder;
 import org.keycloak.client.testsuite.models.Constants;
@@ -70,8 +71,8 @@ public static Keycloak createAdminClient(boolean ignoreUnknownProperties, String
 
     public static Keycloak createAdminClientWithClientCredentials(String realmName, String clientId, String clientSecret, String scope) {
 
-        boolean ignoreUnknownProperties = false;
-        ResteasyClient resteasyClient = createResteasyClient(ignoreUnknownProperties, null);
+        boolean ignoreUnknownProperties = true;
+        ResteasyClient resteasyClient = createResteasyClient(null);
 
         return KeycloakBuilder.builder()
                 .serverUrl(getAuthServerContextRoot())
@@ -91,29 +92,14 @@ public static Keycloak createAdminClient(boolean ignoreUnknownProperties) throws
         return createAdminClient(ignoreUnknownProperties, getAuthServerContextRoot());
     }
 
-    public static ResteasyClient createResteasyClient() {
-        try {
-            return createResteasyClient(false, null);
-        } catch (Exception e) {
-            throw new RuntimeException(e);
-        }
-    }
-
-    public static ResteasyClient createResteasyClient(boolean ignoreUnknownProperties, Boolean followRedirects) {
+    public static ResteasyClient createResteasyClient(Boolean followRedirects) {
         ResteasyClientBuilder resteasyClientBuilder = (ResteasyClientBuilder) ResteasyClientBuilder.newBuilder();
         resteasyClientBuilder.sslContext(buildSslContext());
 
-        // We need to ignore unknown JSON properties e.g. in the adapter configuration representation
-        // during adapter backward compatibility testing
-        if (ignoreUnknownProperties) {
-            // We need to use anonymous class to avoid the following error from RESTEasy:
-            // Provider class org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider is already registered.  2nd registration is being ignored.
-            ResteasyJackson2Provider jacksonProvider = new ResteasyJackson2Provider() {};
-            ObjectMapper objectMapper = new ObjectMapper();
-            objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
-            jacksonProvider.setMapper(objectMapper);
-            resteasyClientBuilder.register(jacksonProvider, 100);
-        }
+        // We need to use subclass (or anonymous class) to avoid the following error from RESTEasy:
+        // Provider class org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider is already registered.  2nd registration is being ignored.
+        ResteasyJackson2Provider jacksonProvider = new JacksonProvider();
+        resteasyClientBuilder.register(jacksonProvider, 100);
 
         resteasyClientBuilder
                 .hostnameVerification(ResteasyClientBuilder.HostnameVerificationPolicy.WILDCARD)