THRIFT-4573 Support binary fields in union counts
This commit also fixes another, related issue: Since union support was
added in b3654df, `Count*` methods (and count checks in `Write`
methods) were only generated if there was at least 1 pointer field.
But pointer fields are not the only nullable types in Go, slices and
maps can also be set the nil, which are now taken into account.
Client: go
diff --git a/lib/go/test/UnionBinaryTest.thrift b/lib/go/test/UnionBinaryTest.thrift
new file mode 100644
index 0000000..f77112b
--- /dev/null
+++ b/lib/go/test/UnionBinaryTest.thrift
@@ -0,0 +1,25 @@
+#
+# 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.
+#
+
+# See https://issues.apache.org/jira/browse/THRIFT-4573
+union Sample {
+ 1: map<string, string> u1,
+ 2: binary u2,
+ 3: list<string> u3
+}