Merge pull request #10619 from alno/top_level_array_in_postgres_json

Support array as root element in Postgresql JSON columns

activerecord/lib/active_record/connection_adapters/postgresql/cast.rb

@@ -60,7 +60,7 @@ def string_to_hstore(string)
         end
 
         def json_to_string(object)
-          if Hash === object
+          if Hash === object || Array === object
             ActiveSupport::JSON.encode(object)
           else
             object

activerecord/lib/active_record/connection_adapters/postgresql/quoting.rb

@@ -30,6 +30,7 @@ def quote(value, column = nil) #:nodoc:
           when Array
             case sql_type
             when 'point' then super(PostgreSQLColumn.point_to_string(value))
+            when 'json' then super(PostgreSQLColumn.json_to_string(value))
             else
               if column.array
                 "'#{PostgreSQLColumn.array_to_string(value, column, self).gsub(/'/, "''")}'"
@@ -98,6 +99,7 @@ def type_cast(value, column, array_member = false)
           when Array
             case column.sql_type
             when 'point' then PostgreSQLColumn.point_to_string(value)
+            when 'json' then PostgreSQLColumn.json_to_string(value)
             else
               return super(value, column) unless column.array
               PostgreSQLColumn.array_to_string(value, column, self)

activerecord/test/cases/adapters/postgresql/json_test.rb

@@ -83,4 +83,18 @@ def test_null_json
     x = JsonDataType.first
     assert_equal(nil, x.payload)
   end
+
+  def test_select_array_json_value
+    @connection.execute %q|insert into json_data_type (payload) VALUES ('["v0",{"k1":"v1"}]')|
+    x = JsonDataType.first
+    assert_equal(['v0', {'k1' => 'v1'}], x.payload)
+  end
+
+  def test_rewrite_array_json_value
+    @connection.execute %q|insert into json_data_type (payload) VALUES ('["v0",{"k1":"v1"}]')|
+    x = JsonDataType.first
+    x.payload = ['v1', {'k2' => 'v2'}, 'v3']
+    assert x.save!
+  end
+
 end