From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Sat, 2 Jan 2021 21:45:06 +0000 (+0100)
Subject: Work around __weakref__ + __slots__ + Generics bug on Python 3.6
X-Git-Tag: 3.0.dev0~204
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=eb9094287296c8b555bb5d579a0261022eb0a583;p=thirdparty%2Fpsycopg.git

Work around __weakref__ + __slots__ + Generics bug on Python 3.6

See bug https://bugs.python.org/issue41451
---

diff --git a/psycopg3/psycopg3/cursor.py b/psycopg3/psycopg3/cursor.py
index d03428b20..0c0d092fa 100644
--- a/psycopg3/psycopg3/cursor.py
+++ b/psycopg3/psycopg3/cursor.py
@@ -45,11 +45,15 @@ else:
 
 
 class BaseCursor(Generic[ConnectionType]):
-    __slots__ = """
-        _conn format _adapters arraysize _closed _results _pgresult _pos
-        _iresult _rowcount _query _params _transformer
-        __weakref__
-        """.split()
+    # Slots with __weakref__ and generic bases don't work on Py 3.6
+    # https://bugs.python.org/issue41451
+    if sys.version_info >= (3, 7):
+        __slots__ = """
+            _conn format _adapters arraysize _closed _results _pgresult _pos
+            _iresult _rowcount _query _params _transformer
+            __weakref__
+            """.split()
+
     ExecStatus = pq.ExecStatus
 
     _transformer: "Transformer"