Fix segfault initialising Column object manually

Close psycopg#1252

Author: dvarrazzo

NEWS

@@ -13,7 +13,8 @@ What's new in psycopg 2.9
 What's new in psycopg 2.8.7
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-Accept empty params as `~psycopg2.connect()` (:ticket:`#1250).
+- Accept empty params as `~psycopg2.connect()` (:ticket:`#1250).
+- Fix attributes refcount in `Column` initialisation (:ticket:`#1252`).
 
 
 What's new in psycopg 2.8.6

psycopg/column_type.c

@@ -97,17 +97,36 @@ column_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 static int
 column_init(columnObject *self, PyObject *args, PyObject *kwargs)
 {
+    PyObject *name = NULL;
+    PyObject *type_code = NULL;
+    PyObject *display_size = NULL;
+    PyObject *internal_size = NULL;
+    PyObject *precision = NULL;
+    PyObject *scale = NULL;
+    PyObject *null_ok = NULL;
+    PyObject *table_oid = NULL;
+    PyObject *table_column = NULL;
+
     static char *kwlist[] = {
         "name", "type_code", "display_size", "internal_size",
         "precision", "scale", "null_ok", "table_oid", "table_column", NULL};
 
     if (!PyArg_ParseTupleAndKeywords(args, kwargs, "|OOOOOOOOO", kwlist,
-            &self->name, &self->type_code, &self->display_size,
-            &self->internal_size, &self->precision, &self->scale,
-            &self->null_ok, &self->table_oid, &self->table_column)) {
+            &name, &type_code, &display_size, &internal_size, &precision,
+            &scale, &null_ok, &table_oid, &table_column)) {
         return -1;
     }
 
+    Py_XINCREF(name); self->name = name;
+    Py_XINCREF(type_code); self->type_code = type_code;
+    Py_XINCREF(display_size); self->display_size = display_size;
+    Py_XINCREF(internal_size); self->internal_size = internal_size;
+    Py_XINCREF(precision); self->precision = precision;
+    Py_XINCREF(scale); self->scale = scale;
+    Py_XINCREF(null_ok); self->null_ok = null_ok;
+    Py_XINCREF(table_oid); self->table_oid = table_oid;
+    Py_XINCREF(table_column); self->table_column = table_column;
+
     return 0;
 }
 

tests/test_cursor.py

@@ -250,6 +250,16 @@ def test_pickle_description(self):
 
         self.assertEqual(description, unpickled)
 
+    def test_column_refcount(self):
+        # Reproduce crash describe in ticket #1252
+        from psycopg2.extensions import Column
+
+        def do_stuff():
+            _ = Column(name='my_column')
+
+        for _ in range(1000):
+            do_stuff()
+
     def test_bad_subclass(self):
         # check that we get an error message instead of a segfault
         # for badly written subclasses.