[service] Fix KvQueryClient hang when query location lookup fails on retry

paimon-service/paimon-service-client/src/main/java/org/apache/paimon/service/client/KvQueryClient.java

@@ -99,8 +99,14 @@ private void executeActionAsync(
 
     private CompletableFuture<KvResponse> getResponse(
             final KvRequest request, final boolean forceUpdate) {
-        InetSocketAddress serverAddress =
-                queryLocation.getLocation(request.partition(), request.bucket(), forceUpdate);
+        InetSocketAddress serverAddress;
+        try {
+            serverAddress =
+                    queryLocation.getLocation(request.partition(), request.bucket(), forceUpdate);
+        } catch (Exception e) {
+            LOG.error("Failed to get location for bucket: " + request.bucket(), e);
+            return FutureUtils.completedExceptionally(e);
+        }
         if (serverAddress == null) {
             return FutureUtils.completedExceptionally(
                     new RuntimeException("Cannot find address for bucket: " + request.bucket()));

paimon-service/paimon-service-runtime/src/test/java/org/apache/paimon/service/client/KvQueryClientLocationFailureTest.java

@@ -0,0 +1,91 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.paimon.service.client;
+
+import org.apache.paimon.data.BinaryRow;
+import org.apache.paimon.query.QueryLocation;
+
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.ServerSocket;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
+
+/** Test for {@link KvQueryClient} when the query location lookup fails. */
+public class KvQueryClientLocationFailureTest {
+
+    private static final String LOCATION_FAILURE = "Cannot find address for table path: /test/path";
+
+    private KvQueryClient client;
+
+    @AfterEach
+    public void afterEach() {
+        if (client != null) {
+            client.shutdown();
+            client = null;
+        }
+    }
+
+    /**
+     * The retried location lookup happens inside a callback of the previous request, so a
+     * synchronous throw there must be turned into an exceptionally completed future. Otherwise the
+     * future returned by {@link KvQueryClient#getValues} is never completed at all.
+     */
+    @Test
+    public void testLocationLookupThrowingOnRetryCompletesFuture() throws Exception {
+        InetSocketAddress unreachable = unusedLocalAddress();
+        AtomicInteger lookups = new AtomicInteger();
+        QueryLocation queryLocation =
+                (partition, bucket, forceUpdate) -> {
+                    lookups.incrementAndGet();
+                    if (forceUpdate) {
+                        // this is what QueryLocationImpl does once the service file is gone
+                        throw new RuntimeException(LOCATION_FAILURE);
+                    }
+                    // valid address, but nothing listens on it: the connect fails with a
+                    // ConnectException, which triggers the forced location update above
+                    return unreachable;
+                };
+
+        client = new KvQueryClient(queryLocation, 1);
+        CompletableFuture<BinaryRow[]> future =
+                client.getValues(BinaryRow.EMPTY_ROW, 0, new BinaryRow[] {BinaryRow.EMPTY_ROW});
+
+        assertThatThrownBy(() -> future.get(10, TimeUnit.SECONDS))
+                .isInstanceOf(ExecutionException.class)
+                .hasRootCauseMessage(LOCATION_FAILURE);
+        assertThat(lookups.get()).isEqualTo(2);
+    }
+
+    private static InetSocketAddress unusedLocalAddress() throws IOException {
+        InetAddress loopback = InetAddress.getLoopbackAddress();
+        try (ServerSocket socket = new ServerSocket(0, 1, loopback)) {
+            return new InetSocketAddress(loopback, socket.getLocalPort());
+        }
+    }
+}