bpo-43977: Use tp_flags for collection matching (GH-25723)
* Add Py_TPFLAGS_SEQUENCE and Py_TPFLAGS_MAPPING, add to all relevant standard builtin classes.
* Set relevant flags on collections.abc.Sequence and Mapping.
* Use flags in MATCH_SEQUENCE and MATCH_MAPPING opcodes.
* Inherit Py_TPFLAGS_SEQUENCE and Py_TPFLAGS_MAPPING.
* Add NEWS
* Remove interpreter-state map_abc and seq_abc fields.
diff --git a/Include/internal/pycore_interp.h b/Include/internal/pycore_interp.h
index 11d31da..bfd082b 100644
--- a/Include/internal/pycore_interp.h
+++ b/Include/internal/pycore_interp.h
@@ -247,10 +247,6 @@ struct _is {
// importlib module
PyObject *importlib;
- // Kept handy for pattern matching:
- PyObject *map_abc; // _collections_abc.Mapping
- PyObject *seq_abc; // _collections_abc.Sequence
-
/* Used in Modules/_threadmodule.c. */
long num_threads;
/* Support for runtime thread stack size tuning.
diff --git a/Include/object.h b/Include/object.h
index d8476f9..cffe72c 100644
--- a/Include/object.h
+++ b/Include/object.h
@@ -320,6 +320,13 @@ Code can use PyType_HasFeature(type_ob, flag_value) to test whether the
given type object has a specified feature.
*/
+#ifndef Py_LIMITED_API
+/* Set if instances of the type object are treated as sequences for pattern matching */
+#define Py_TPFLAGS_SEQUENCE (1 << 5)
+/* Set if instances of the type object are treated as mappings for pattern matching */
+#define Py_TPFLAGS_MAPPING (1 << 6)
+#endif
+
/* Set if the type object is immutable: type attributes cannot be set nor deleted */
#define Py_TPFLAGS_IMMUTABLETYPE (1UL << 8)