From 2e239f7148c852b7b7e2de4af66e8e5707d9d049 Mon Sep 17 00:00:00 2001
From: Mike Kaplinskiy <mike.kaplinskiy@gmail.com>
Date: Thu, 7 Feb 2019 08:00:29 -0800
Subject: [PATCH] Empty table results can have a schema (#4185)

* Update EmptyTableResult.java

* Update Job.java

* add test case
---
 .../cloud/bigquery/EmptyTableResult.java      |  5 +-
 .../java/com/google/cloud/bigquery/Job.java   |  2 +-
 .../com/google/cloud/bigquery/JobTest.java    | 49 +++++++++++++++++++
 3 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/google-cloud-clients/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/EmptyTableResult.java b/google-cloud-clients/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/EmptyTableResult.java
index 68112ef0b5ee..7cb5e1932fa3 100644
--- a/google-cloud-clients/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/EmptyTableResult.java
+++ b/google-cloud-clients/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/EmptyTableResult.java
@@ -18,6 +18,7 @@
 
 import com.google.api.core.InternalApi;
 import com.google.cloud.PageImpl;
+import javax.annotation.Nullable;
 
 public class EmptyTableResult extends TableResult {
 
@@ -25,7 +26,7 @@ public class EmptyTableResult extends TableResult {
 
   /** An empty {@code TableResult} to avoid making API requests to unlistable tables. */
   @InternalApi("Exposed for testing")
-  public EmptyTableResult() {
-    super(null, 0, new PageImpl<FieldValueList>(null, "", null));
+  public EmptyTableResult(@Nullable Schema schema) {
+    super(schema, 0, new PageImpl<FieldValueList>(null, "", null));
   }
 }
diff --git a/google-cloud-clients/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/Job.java b/google-cloud-clients/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/Job.java
index 9a61192c4045..de018291d9d2 100644
--- a/google-cloud-clients/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/Job.java
+++ b/google-cloud-clients/google-cloud-bigquery/src/main/java/com/google/cloud/bigquery/Job.java
@@ -305,7 +305,7 @@ public TableResult getQueryResults(QueryResultsOption... options)
     // Listing table data might fail, such as with CREATE VIEW queries.
     // Avoid a tabledata.list API request by returning an empty TableResult.
     if (response.getTotalRows() == 0) {
-      return new EmptyTableResult();
+      return new EmptyTableResult(response.getSchema());
     }
 
     TableId table = ((QueryJobConfiguration) getConfiguration()).getDestinationTable();
diff --git a/google-cloud-clients/google-cloud-bigquery/src/test/java/com/google/cloud/bigquery/JobTest.java b/google-cloud-clients/google-cloud-bigquery/src/test/java/com/google/cloud/bigquery/JobTest.java
index 57c6a1104eab..b259b237ea78 100644
--- a/google-cloud-clients/google-cloud-bigquery/src/test/java/com/google/cloud/bigquery/JobTest.java
+++ b/google-cloud-clients/google-cloud-bigquery/src/test/java/com/google/cloud/bigquery/JobTest.java
@@ -302,6 +302,55 @@ public Iterable<FieldValueList> getValues() {
     verify(status, mockOptions);
   }
 
+  @Test
+  public void testWaitForAndGetQueryResultsEmptyWithSchema() throws InterruptedException {
+    QueryJobConfiguration jobConfig =
+        QueryJobConfiguration.newBuilder("CREATE VIEW").setDestinationTable(TABLE_ID1).build();
+    QueryStatistics jobStatistics =
+        QueryStatistics.newBuilder()
+            .setCreationTimestamp(1L)
+            .setEndTime(3L)
+            .setStartTime(2L)
+            .build();
+    JobInfo jobInfo =
+        JobInfo.newBuilder(jobConfig)
+            .setJobId(JOB_ID)
+            .setStatistics(jobStatistics)
+            .setJobId(JOB_ID)
+            .setEtag(ETAG)
+            .setGeneratedId(GENERATED_ID)
+            .setSelfLink(SELF_LINK)
+            .setUserEmail(EMAIL)
+            .setStatus(JOB_STATUS)
+            .build();
+
+    initializeExpectedJob(2, jobInfo);
+    JobStatus status = createStrictMock(JobStatus.class);
+    expect(bigquery.getOptions()).andReturn(mockOptions);
+    expect(mockOptions.getClock()).andReturn(CurrentMillisClock.getDefaultClock()).times(2);
+    Job completedJob = expectedJob.toBuilder().setStatus(status).build();
+    QueryResponse completedQuery =
+        QueryResponse.newBuilder()
+            .setCompleted(true)
+            .setTotalRows(0)
+            .setSchema(Schema.of(Field.of("field1", LegacySQLTypeName.BOOLEAN)))
+            .setErrors(ImmutableList.<BigQueryError>of())
+            .build();
+
+    expect(bigquery.getQueryResults(jobInfo.getJobId(), Job.DEFAULT_QUERY_WAIT_OPTIONS))
+        .andReturn(completedQuery);
+    expect(bigquery.getJob(JOB_INFO.getJobId())).andReturn(completedJob);
+    expect(bigquery.getQueryResults(jobInfo.getJobId(), Job.DEFAULT_QUERY_WAIT_OPTIONS))
+        .andReturn(completedQuery);
+
+    replay(status, bigquery, mockOptions);
+    initializeJob(jobInfo);
+    assertThat(job.waitFor(TEST_RETRY_OPTIONS)).isSameAs(completedJob);
+    assertThat(job.getQueryResults().getSchema())
+        .isEqualTo(Schema.of(Field.of("field1", LegacySQLTypeName.BOOLEAN)));
+    verify(status, mockOptions);
+  }
+
   @Test
   public void testWaitForAndGetQueryResults() throws InterruptedException {
     QueryJobConfiguration jobConfig =