Ensure Result#fields and #rows are always arrays

Fix: #282

Author: byroot

contrib/ruby/lib/trilogy/result.rb

@@ -2,9 +2,12 @@ class Trilogy
   class Result
     attr_reader :fields, :rows, :query_time, :affected_rows, :last_insert_id
 
+    EMPTY_ARRAY = [].freeze
+    private_constant :EMPTY_ARRAY
+
     def initialize(fields, rows, query_time, in_transaction, affected_rows, last_insert_id)
-      @fields = fields
-      @rows = rows
+      @fields = fields || EMPTY_ARRAY
+      @rows = rows || EMPTY_ARRAY
       @query_time = query_time
       @in_transaction = in_transaction
       @affected_rows = affected_rows

contrib/ruby/test/client_test.rb

@@ -264,7 +264,10 @@ def test_trilogy_query_values
 
     client.query("INSERT INTO trilogy_test (int_test) VALUES ('4')")
     client.query("INSERT INTO trilogy_test (int_test) VALUES ('3')")
-    client.query("INSERT INTO trilogy_test (int_test) VALUES ('1')")
+    result = client.query("INSERT INTO trilogy_test (int_test) VALUES ('1')")
+
+    assert_equal [], result.fields
+    assert_equal [], result.rows
 
     result = client.query_with_flags("SELECT id, int_test FROM trilogy_test", client.query_flags | Trilogy::QUERY_FLAGS_FLATTEN_ROWS)