fix(bigquery): reject incomplete job for Arrow query format with UnsupportedOperationException

Author: jinseopkim0

java-bigquery/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/BigQueryImpl.java

@@ -2498,13 +2498,10 @@ && getOptions().getOpenTelemetryTracer() != null) {
       throw new BigQueryException(bigQueryErrors);
     }
 
-    // If query is incomplete, fallback to fetching the Job.
+    // If query is incomplete, Arrow format for slow query path is not yet supported.
     if (!Boolean.TRUE.equals(results.getJobComplete())) {
-      if (results.getJobReference() == null) {
-        throw new BigQueryException(0, "Job is incomplete, but no job reference was returned.");
-      }
-      JobId jobId = JobId.fromPb(results.getJobReference());
-      return getJob(jobId, options);
+      throw new UnsupportedOperationException(
+          "Arrow results format for slow query path execution is not yet supported.");
     }
 
     // If query is complete but Arrow schema is missing or invalid, fallback to standard JSON

java-bigquery/google-cloud-bigquery/src/test/java/com/google/cloud/bigquery/BigQueryImplTest.java

@@ -3287,6 +3287,31 @@ void testQueryWithArrowFormatMissingSerializedSchema() throws Exception {
     assertTrue(e.getMessage().contains("Arrow schema is missing from the response"));
   }
 
+  @Test
+  void testQueryWithArrowFormatIncompleteJob() throws Exception {
+    JobId queryJob = JobId.of(PROJECT, JOB).toBuilder().setLocation(LOCATION).build();
+    com.google.api.services.bigquery.model.QueryResponse queryResponsePb =
+        new com.google.api.services.bigquery.model.QueryResponse()
+            .setQueryId("q-arrow-incomplete")
+            .setJobComplete(false)
+            .setJobReference(queryJob.toPb());
+
+    when(bigqueryRpcMock.queryRpcSkipExceptionTranslation(eq(PROJECT), any(QueryRequest.class)))
+        .thenReturn(queryResponsePb);
+
+    bigquery = options.getService();
+
+    QueryJobConfiguration config =
+        QueryJobConfiguration.newBuilder("SELECT id FROM test")
+            .setQueryResultsFormat(QueryResultsFormat.ARROW)
+            .build();
+    UnsupportedOperationException e =
+        assertThrows(UnsupportedOperationException.class, () -> bigquery.query(config));
+    assertTrue(
+        e.getMessage()
+            .contains("Arrow results format for slow query path execution is not yet supported."));
+  }
+
   @Test
   void testGetQueryResults() throws IOException {
     JobId queryJob = JobId.of(JOB);