Merge pull request #239 from danielmerken/fix-null-empty-arrays

fix handling of empty/null arrays

internal/contentdata/repository.go

@@ -222,6 +222,10 @@ func (r *Repository) Query(ctx context.Context, tx *connection.Tx, projectID, da
 		resultValues := make([]interface{}, 0, len(values))
 		for idx, value := range values {
 			v := reflect.ValueOf(value).Elem().Interface()
+			if v == nil && fields[idx].Mode == string(types.RepeatedMode) {
+				// GoogleSQL for BigQuery translates a NULL array into an empty array in the query result
+				v = []interface{}{}
+			}
 			cell, err := r.convertValueToCell(v)
 			if err != nil {
 				return nil, fmt.Errorf("failed to convert value to cell: %w", err)
@@ -315,8 +319,8 @@ func (r *Repository) convertValueToCell(value interface{}) (*internaltypes.Table
 	}
 	// array type
 	var (
-		cells      []*internaltypes.TableCell
-		totalBytes int64
+		cells            = []*internaltypes.TableCell{}
+		totalBytes int64 = 0
 	)
 	for i := 0; i < rv.Len(); i++ {
 		cell, err := r.convertValueToCell(rv.Index(i).Interface())

server/server_test.go

@@ -73,6 +73,48 @@ func TestSimpleQuery(t *testing.T) {
 			t.Log("row = ", row)
 		}
 	})
+
+	t.Run("empty array", func(t *testing.T) {
+		query := client.Query("SELECT []")
+		it, err := query.Read(ctx)
+		if err != nil {
+			t.Fatal(err)
+		}
+		var row []bigquery.Value
+		for {
+			if err := it.Next(&row); err != nil {
+				if err == iterator.Done {
+					break
+				}
+				t.Fatal(err)
+			}
+			t.Log("row = ", row)
+		}
+		if len(row) != 1 || row[0] == nil {
+			t.Fatal("Failed to query empty ARRAY")
+		}
+	})
+
+	t.Run("null array", func(t *testing.T) {
+		query := client.Query("SELECT CAST(NULL AS ARRAY<STRING>)")
+		it, err := query.Read(ctx)
+		if err != nil {
+			t.Fatal(err)
+		}
+		var row []bigquery.Value
+		for {
+			if err := it.Next(&row); err != nil {
+				if err == iterator.Done {
+					break
+				}
+				t.Fatal(err)
+			}
+			t.Log("row = ", row)
+		}
+		if len(row) != 1 || row[0] == nil {
+			t.Fatal("Failed to query null ARRAY")
+		}
+	})
 }
 
 func TestDataset(t *testing.T) {