Enable tests in test_c_struct_sequence.py for Python 3.11, 3.12. Add note about unnamed fields failure in Python 3.9, 3.10.

Author: paulross

doc/sphinx/source/struct_sequence.rst

@@ -666,6 +666,12 @@ These are fields unavailable to Python code but available to C code.
 The rules using these are quite involved and the Python documentation is poor at describing them so I'll do my best
 here.
 
+.. note::
+
+    Unnamed fields doe not appear to work in Python versions prior to 3.11 with the following compile time error:
+
+    ``E   ImportError: dlopen(... cStructSequence.cpython-310-darwin.so, 0x0002): symbol not found in flat namespace '_PyStructSequence_UnnamedField'``
+
 The rules appear to be:
 
 * Unnamed fields in the `PyStructSequence_Field`_ *must* follow named fields.

src/cpy/StructSequence/cStructSequence.c

@@ -383,6 +383,9 @@ ExcessNT_create(PyObject *Py_UNUSED(module), PyObject *args, PyObject *kwds) {
  * Use this for numeric comparisons, e.g. #if PY_VERSION_HEX >= ...
  *
  * This is Python 3.11+ specific code.
+ * Earlier versions give this compile time error:
+ * E   ImportError: dlopen(...cStructSequence.cpython-310-darwin.so, 0x0002): \
+ *  symbol not found in flat namespace '_PyStructSequence_UnnamedField'
  */
 #if PY_VERSION_HEX >= 0x030B0000
 
@@ -481,8 +484,10 @@ static PyMethodDef cStructSequence_methods[] = {
                         "Example of getting a transaction."},
         {"ExcessNT_create",           (PyCFunction) ExcessNT_create,           METH_VARARGS | METH_KEYWORDS,
                         "Create a ExcessNT from the given values."},
-/* Python 3.11 specific code. Earlier versions have a problem with:
- * symbol not found in flat namespace '_PyStructSequence_UnnamedField'
+/* Python 3.11+ specific code.
+ * Earlier versions give this compile time error:
+ * E   ImportError: dlopen(...cStructSequence.cpython-310-darwin.so, 0x0002): \
+ *  symbol not found in flat namespace '_PyStructSequence_UnnamedField'
  */
 #if PY_VERSION_HEX >= 0x030B0000
         {"NTWithUnnamedField_create", (PyCFunction) NTWithUnnamedField_create, METH_VARARGS | METH_KEYWORDS,

tests/unit/test_c_struct_sequence.py

@@ -613,54 +613,54 @@ def test_excess_nt_field_three_index_missing():
     assert err.value.args[0] == 'tuple index out of range'
 
 
-# @pytest.mark.skipif(not (sys.version_info.minor <= 11), reason='Python <= 3.11')
-# def test_nt_with_unnamed_field_create_dir_3_11_and_before():
-#     ntuf = cStructSequence.NTWithUnnamedField_create('foo', 'bar', 'baz')
-#     print()
-#     pprint.pprint(dir(ntuf))
-#     assert dir(ntuf) == [
-#         '__add__',
-#         '__class__',
-#         '__class_getitem__',
-#         '__contains__',
-#         '__delattr__',
-#         '__dir__',
-#         '__doc__',
-#         '__eq__',
-#         '__format__',
-#         '__ge__',
-#         '__getattribute__',
-#         '__getitem__',
-#         '__getnewargs__',
-#         '__getstate__',
-#         '__gt__',
-#         '__hash__',
-#         '__init__',
-#         '__init_subclass__',
-#         '__iter__',
-#         '__le__',
-#         '__len__',
-#         '__lt__',
-#         '__match_args__',
-#         '__module__',
-#         '__mul__',
-#         '__ne__',
-#         '__new__',
-#         '__reduce__',
-#         '__reduce_ex__',
-#         '__repr__',
-#         '__rmul__',
-#         '__setattr__',
-#         '__sizeof__',
-#         '__str__',
-#         '__subclasshook__',
-#         'count',
-#         'field_one',
-#         'index',
-#         'n_fields',
-#         'n_sequence_fields',
-#         'n_unnamed_fields'
-#     ]
+@pytest.mark.skipif(not (11 <= sys.version_info.minor <= 12), reason='Python 3.11, 3.12')
+def test_nt_with_unnamed_field_create_dir_3_11_and_before():
+    ntuf = cStructSequence.NTWithUnnamedField_create('foo', 'bar', 'baz')
+    print()
+    pprint.pprint(dir(ntuf))
+    assert dir(ntuf) == [
+        '__add__',
+        '__class__',
+        '__class_getitem__',
+        '__contains__',
+        '__delattr__',
+        '__dir__',
+        '__doc__',
+        '__eq__',
+        '__format__',
+        '__ge__',
+        '__getattribute__',
+        '__getitem__',
+        '__getnewargs__',
+        '__getstate__',
+        '__gt__',
+        '__hash__',
+        '__init__',
+        '__init_subclass__',
+        '__iter__',
+        '__le__',
+        '__len__',
+        '__lt__',
+        '__match_args__',
+        '__module__',
+        '__mul__',
+        '__ne__',
+        '__new__',
+        '__reduce__',
+        '__reduce_ex__',
+        '__repr__',
+        '__rmul__',
+        '__setattr__',
+        '__sizeof__',
+        '__str__',
+        '__subclasshook__',
+        'count',
+        'field_one',
+        'index',
+        'n_fields',
+        'n_sequence_fields',
+        'n_unnamed_fields',
+    ]
 
 
 @pytest.mark.skipif(not (sys.version_info.minor >= 13), reason='Python 3.13+')