Return Redis sets as Python lists (#189)

In some (rare) cases, the sets from a Redis response contain nested
types that are not hashable in Python, for example maps. To handle these
cases uniformly, always return Python lists for Redis sets. The elements
will still be unique, relying on the correctness of data arriving from
the server.

This is a breaking change, although in reality it might not have a big 
impact. Therefore the major version gets bumped to 3.

hiredis/version.py

@@ -1 +1 @@
-__version__ = "2.4.0"
+__version__ = "3.0.0"

src/reader.c

@@ -82,10 +82,6 @@ static void *tryParentize(const redisReadTask *task, PyObject *obj) {
                     PyDict_SetItem(parent, last_key, obj);
                 }
                 break;
-            case REDIS_REPLY_SET:
-                assert(PyAnySet_CheckExact(parent));
-                PySet_Add(parent, obj);
-                break;
             default:
                 assert(PyList_CheckExact(parent));
                 PyList_SET_ITEM(parent, task->idx, obj);
@@ -162,9 +158,6 @@ static void *createArrayObject(const redisReadTask *task, size_t elements) {
         case REDIS_REPLY_MAP:
             obj = PyDict_New();
             break;
-        case REDIS_REPLY_SET:
-            obj = PySet_New(NULL);
-            break;
         default:
             obj = PyList_New(elements);
     }

tests/test_reader.py

@@ -136,7 +136,11 @@ def test_none(reader):
 
 def test_set(reader):
   reader.feed(b"~3\r\n+tangerine\r\n_\r\n,10.5\r\n")
-  assert {b"tangerine", None, 10.5} == reader.gets()
+  assert [b"tangerine", None, 10.5] == reader.gets()
+
+def test_set_with_nested_dict(reader):
+  reader.feed(b"~2\r\n+tangerine\r\n%1\r\n+a\r\n:1\r\n")
+  assert [b"tangerine", {b"a": 1}] == reader.gets()
 
 def test_dict(reader):
   reader.feed(b"%2\r\n+radius\r\n,4.5\r\n+diameter\r\n:9\r\n")