[hotfix] Fix old client can't connect to new server (#1086)

Author: luoyuxia

fluss-rpc/src/main/java/com/alibaba/fluss/rpc/netty/client/ServerApiVersions.java

@@ -35,9 +35,7 @@ final class ServerApiVersions {
     ServerApiVersions(Collection<PbApiVersion> serverApiVersions) {
         for (PbApiVersion serverVersion : serverApiVersions) {
             if (!ApiKeys.hasId(serverVersion.getApiKey())) {
-                throw new IllegalArgumentException(
-                        "Server returned an API version which is not supported by this client: "
-                                + serverVersion.getApiKey());
+                continue;
             }
             ApiKeys apiKey = ApiKeys.forId(serverVersion.getApiKey());
             Optional<Short> version =

fluss-rpc/src/test/java/com/alibaba/fluss/rpc/netty/client/ServerApiVersionsTest.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2025 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.alibaba.fluss.rpc.netty.client;
+
+import com.alibaba.fluss.cluster.ServerType;
+import com.alibaba.fluss.rpc.messages.PbApiVersion;
+import com.alibaba.fluss.rpc.protocol.ApiKeys;
+import com.alibaba.fluss.rpc.protocol.ApiManager;
+
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/** The unit test for {@link ServerApiVersions}. */
+class ServerApiVersionsTest {
+
+    @Test
+    void testClientUnSupportedApiVersions() {
+        ApiManager apiManager = new ApiManager(ServerType.TABLET_SERVER);
+        Set<ApiKeys> apiKeys = apiManager.enabledApis();
+        List<PbApiVersion> apiVersions = new ArrayList<>();
+        for (ApiKeys api : apiKeys) {
+            apiVersions.add(
+                    new PbApiVersion()
+                            .setApiKey(api.id)
+                            .setMinVersion(api.lowestSupportedVersion)
+                            .setMaxVersion(api.highestSupportedVersion));
+        }
+        // add a api key that client don't support, we use -1 as apiKey to mock
+        // the client unsupported api key
+        apiVersions.add(new PbApiVersion().setApiKey(-1).setMinVersion(0).setMaxVersion(0));
+
+        ServerApiVersions serverApiVersions = new ServerApiVersions(apiVersions);
+        // verify we get get highest available version for supported api key
+        assertThat(serverApiVersions.highestAvailableVersion(ApiKeys.API_VERSIONS))
+                .isEqualTo(ApiKeys.API_VERSIONS.highestSupportedVersion);
+    }
+}