Fix crash on connection attribute lookup with non-string names (#810)

Author: methane

src/MySQLdb/_mysql.c

@@ -2968,9 +2968,8 @@ _mysql_ConnectionObject_getattro(
     _mysql_ConnectionObject *self,
     PyObject *name)
 {
-    const char *cname;
-    cname = PyUnicode_AsUTF8(name);
-    if (strcmp(cname, "closed") == 0)
+    if (PyUnicode_Check(name) &&
+            PyUnicode_CompareWithASCIIString(name, "closed") == 0)
         return PyLong_FromLong((long)!(self->open));
 
     return PyObject_GenericGetAttr((PyObject *)self, name);

tests/test__mysql.py

@@ -1,8 +1,36 @@
 import pytest
 
 from MySQLdb import _mysql
+from MySQLdb.connections import Connection
 
 
 def test_result_type():
     with pytest.raises(TypeError):
         _mysql.result(b"xyz")
+
+
+@pytest.mark.parametrize("connection_type", [_mysql.connection, Connection])
+@pytest.mark.parametrize("name", [5, None, b"closed", [], {}])
+def test_connection_getattribute_non_string(connection_type, name):
+    conn = connection_type.__new__(connection_type)
+    with pytest.raises(TypeError):
+        conn.__getattribute__(name)
+
+
+@pytest.mark.parametrize("connection_type", [_mysql.connection, Connection])
+@pytest.mark.parametrize("name", ["missing", "closed\x00suffix", "\ud800"])
+def test_connection_getattribute_missing(connection_type, name):
+    conn = connection_type.__new__(connection_type)
+    with pytest.raises(AttributeError):
+        conn.__getattribute__(name)
+
+
+@pytest.mark.parametrize("connection_type", [_mysql.connection, Connection])
+def test_connection_getattribute(connection_type):
+    class AttributeName(str):
+        pass
+
+    conn = connection_type.__new__(connection_type)
+    assert conn.closed == 1
+    assert conn.__getattribute__(AttributeName("closed")) == 1
+    assert conn.__class__ is connection_type