Remove _set_parameter_types

Python, in general, works on protocols rather than nominal or specific types. I think this check is overly restrictive, with only minor benefit. Users wanting validation can use static type checkers.
python · AA-Turner · May 6, 2025 · Apr 30, 2025 · Apr 30, 2025 · May 3, 2025
commit bf4b07daade1a55da151db571fc581d80899e8db
diff --git a/Lib/compression/zstd/__init__.py b/Lib/compression/zstd/__init__.py
@@ -228,7 +228,3 @@ class Strategy(enum.IntEnum):
     btopt = _zstd._ZSTD_btopt
     btultra = _zstd._ZSTD_btultra
     btultra2 = _zstd._ZSTD_btultra2
-
-
-# Check validity of the CompressionParameter & DecompressionParameter types
-_zstd._set_parameter_types(CompressionParameter, DecompressionParameter)
diff --git a/Modules/_zstd/_zstdmodule.c b/Modules/_zstd/_zstdmodule.c
@@ -510,49 +510,12 @@ _zstd__get_frame_info_impl(PyObject *module, Py_buffer *frame_buffer)
     return Py_BuildValue("KI", decompressed_size, dict_id);
 }
 
-/*[clinic input]
-_zstd._set_parameter_types
-
-    c_parameter_type: object(subclass_of='&PyType_Type')
-        CompressionParameter IntEnum type object
-    d_parameter_type: object(subclass_of='&PyType_Type')
-        DecompressionParameter IntEnum type object
-
-Internal function, set CompressionParameter/DecompressionParameter types for validity check.
-[clinic start generated code]*/
-
-static PyObject *
-_zstd__set_parameter_types_impl(PyObject *module, PyObject *c_parameter_type,
-                                PyObject *d_parameter_type)
-/*[clinic end generated code: output=a13d4890ccbd2873 input=4535545d903853d3]*/
-{
-    _zstd_state* const mod_state = get_zstd_state(module);
-
-    if (!PyType_Check(c_parameter_type) || !PyType_Check(d_parameter_type)) {
-        PyErr_SetString(PyExc_ValueError,
-                        "The two arguments should be CompressionParameter and "
-                        "DecompressionParameter types.");
-        return NULL;
-    }
-
-    Py_XDECREF(mod_state->CParameter_type);
-    Py_INCREF(c_parameter_type);
-    mod_state->CParameter_type = (PyTypeObject*)c_parameter_type;
-
-    Py_XDECREF(mod_state->DParameter_type);
-    Py_INCREF(d_parameter_type);
-    mod_state->DParameter_type = (PyTypeObject*)d_parameter_type;
-
-    Py_RETURN_NONE;
-}
-
 static PyMethodDef _zstd_methods[] = {
     _ZSTD__TRAIN_DICT_METHODDEF
     _ZSTD__FINALIZE_DICT_METHODDEF
     _ZSTD__GET_PARAM_BOUNDS_METHODDEF
     _ZSTD_GET_FRAME_SIZE_METHODDEF
     _ZSTD__GET_FRAME_INFO_METHODDEF
-    _ZSTD__SET_PARAMETER_TYPES_METHODDEF
 
     {0}
 };
@@ -766,9 +729,6 @@ static int _zstd_exec(PyObject *module) {
     ADD_STR_TO_STATE_MACRO(write);
     ADD_STR_TO_STATE_MACRO(flush);
 
-    mod_state->CParameter_type = NULL;
-    mod_state->DParameter_type = NULL;
-
     /* Add variables to module */
     if (add_vars_to_module(module) < 0) {
         return -1;
@@ -852,9 +812,6 @@ _zstd_traverse(PyObject *module, visitproc visit, void *arg)
     Py_VISIT(mod_state->ZstdDecompressor_type);
 
     Py_VISIT(mod_state->ZstdError);
-
-    Py_VISIT(mod_state->CParameter_type);
-    Py_VISIT(mod_state->DParameter_type);
     return 0;
 }
 
@@ -876,9 +833,6 @@ _zstd_clear(PyObject *module)
     Py_CLEAR(mod_state->ZstdDecompressor_type);
 
     Py_CLEAR(mod_state->ZstdError);
-
-    Py_CLEAR(mod_state->CParameter_type);
-    Py_CLEAR(mod_state->DParameter_type);
     return 0;
 }
 

diff --git a/Modules/_zstd/_zstdmodule.h b/Modules/_zstd/_zstdmodule.h
@@ -54,9 +54,6 @@ struct _zstd_state {
     PyTypeObject *ZstdCompressor_type;
     PyTypeObject *ZstdDecompressor_type;
     PyObject *ZstdError;
-
-    PyTypeObject *CParameter_type;
-    PyTypeObject *DParameter_type;
 };
 
 typedef struct {

diff --git a/Modules/_zstd/clinic/_zstdmodule.c.h b/Modules/_zstd/clinic/_zstdmodule.c.h
diff --git a/Modules/_zstd/compressor.c b/Modules/_zstd/compressor.c
@@ -67,14 +67,6 @@ _PyZstd_set_c_parameters(ZstdCompressor *self, PyObject *level_or_options,
         Py_ssize_t pos = 0;
 
         while (PyDict_Next(level_or_options, &pos, &key, &value)) {
-            /* Check key type */
-            if (Py_TYPE(key) == mod_state->DParameter_type) {
-                PyErr_SetString(PyExc_TypeError,
-                                "Key of compression option dict should "
-                                "NOT be DecompressionParameter.");
-                return -1;
-            }
-
             int key_v = PyLong_AsInt(key);
             if (key_v == -1 && PyErr_Occurred()) {
                 PyErr_SetString(PyExc_ValueError,

diff --git a/Modules/_zstd/decompressor.c b/Modules/_zstd/decompressor.c
@@ -80,14 +80,6 @@ _PyZstd_set_d_parameters(ZstdDecompressor *self, PyObject *options)
 
     pos = 0;
     while (PyDict_Next(options, &pos, &key, &value)) {
-        /* Check key type */
-        if (Py_TYPE(key) == mod_state->CParameter_type) {
-            PyErr_SetString(PyExc_TypeError,
-                            "Key of decompression options dict should "
-                            "NOT be CompressionParameter.");
-            return -1;
-        }
-
         /* Both key & value should be 32-bit signed int */
         int key_v = PyLong_AsInt(key);
         if (key_v == -1 && PyErr_Occurred()) {