Remove obsolete checks for copy.replace support

brianschubert · brianschubert · commit de5564a645c3 · 2025-08-09T19:17:05.000-04:00
diff --git a/Lib/test/test_ast/test_ast.py b/Lib/test/test_ast/test_ast.py
@@ -1412,7 +1412,7 @@ def test_replace_reject_missing_field(self):
 
         self.assertRaises(AttributeError, getattr, node, 'id')
         self.assertIs(node.ctx, context)
-        msg = "Name.__replace__ missing 1 keyword argument: 'id'."
+        msg = "ast.Name.__init__ missing 1 required positional argument: 'id'"
         with self.assertRaisesRegex(TypeError, re.escape(msg)):
             copy.replace(node)
         # assert that there is no side-effect
@@ -1449,7 +1449,7 @@ def test_replace_reject_known_custom_instance_fields_commits(self):
 
         # explicit rejection of known instance fields
         self.assertHasAttr(node, 'extra')
-        msg = "Name.__replace__ got an unexpected keyword argument 'extra'."
+        msg = "ast.Name.__init__ got an unexpected keyword argument 'extra'"
         with self.assertRaisesRegex(TypeError, re.escape(msg)):
             copy.replace(node, extra=1)
         # assert that there is no side-effect
@@ -1463,7 +1463,7 @@ def test_replace_reject_unknown_instance_fields(self):
 
         # explicit rejection of unknown extra fields
         self.assertRaises(AttributeError, getattr, node, 'unknown')
-        msg = "Name.__replace__ got an unexpected keyword argument 'unknown'."
+        msg = "ast.Name.__init__ got an unexpected keyword argument 'unknown'"
         with self.assertRaisesRegex(TypeError, re.escape(msg)):
             copy.replace(node, unknown=1)
         # assert that there is no side-effect
diff --git a/Parser/asdl_c.py b/Parser/asdl_c.py
@@ -1212,182 +1212,6 @@ def visitModule(self, mod):
     return result;
 }
 
-/*
- * Perform the following validations:
- *
- *   - All keyword arguments are known 'fields' or 'attributes'.
- *   - No field or attribute would be left unfilled after copy.replace().
- *
- * On success, this returns 1. Otherwise, set a TypeError
- * exception and returns -1 (no exception is set if some
- * other internal errors occur).
- *
- * Parameters
- *
- *      self          The AST node instance.
- *      dict          The AST node instance dictionary (self.__dict__).
- *      fields        The list of fields (self._fields).
- *      attributes    The list of attributes (self._attributes).
- *      kwargs        Keyword arguments passed to ast_type_replace().
- *
- * The 'dict', 'fields', 'attributes' and 'kwargs' arguments can be NULL.
- *
- * Note: this function can be removed in 3.15 since the verification
- *       will be done inside the constructor.
- */
-static inline int
-ast_type_replace_check(PyObject *self,
-                       PyObject *dict,
-                       PyObject *fields,
-                       PyObject *attributes,
-                       PyObject *kwargs)
-{
-    // While it is possible to make some fast paths that would avoid
-    // allocating objects on the stack, this would cost us readability.
-    // For instance, if 'fields' and 'attributes' are both empty, and
-    // 'kwargs' is not empty, we could raise a TypeError immediately.
-    PyObject *expecting = PySet_New(fields);
-    if (expecting == NULL) {
-        return -1;
-    }
-    if (attributes) {
-        if (_PySet_Update(expecting, attributes) < 0) {
-            Py_DECREF(expecting);
-            return -1;
-        }
-    }
-    // Any keyword argument that is neither a field nor attribute is rejected.
-    // We first need to check whether a keyword argument is accepted or not.
-    // If all keyword arguments are accepted, we compute the required fields
-    // and attributes. A field or attribute is not needed if:
-    //
-    //  1) it is given in 'kwargs', or
-    //  2) it already exists on 'self'.
-    if (kwargs) {
-        Py_ssize_t pos = 0;
-        PyObject *key, *value;
-        while (PyDict_Next(kwargs, &pos, &key, &value)) {
-            int rc = PySet_Discard(expecting, key);
-            if (rc < 0) {
-                Py_DECREF(expecting);
-                return -1;
-            }
-            if (rc == 0) {
-                PyErr_Format(PyExc_TypeError,
-                             "%.400s.__replace__ got an unexpected keyword "
-                             "argument '%U'.", Py_TYPE(self)->tp_name, key);
-                Py_DECREF(expecting);
-                return -1;
-            }
-        }
-    }
-    // check that the remaining fields or attributes would be filled
-    if (dict) {
-        Py_ssize_t pos = 0;
-        PyObject *key, *value;
-        while (PyDict_Next(dict, &pos, &key, &value)) {
-            // Mark fields or attributes that are found on the instance
-            // as non-mandatory. If they are not given in 'kwargs', they
-            // will be shallow-coied; otherwise, they would be replaced
-            // (not in this function).
-            if (PySet_Discard(expecting, key) < 0) {
-                Py_DECREF(expecting);
-                return -1;
-            }
-        }
-        if (attributes) {
-            // Some attributes may or may not be present at runtime.
-            // In particular, now that we checked whether 'kwargs'
-            // is correct or not, we allow any attribute to be missing.
-            //
-            // Note that fields must still be entirely determined when
-            // calling the constructor later.
-            PyObject *unused = PyObject_CallMethodOneArg(expecting,
-                                                         &_Py_ID(difference_update),
-                                                         attributes);
-            if (unused == NULL) {
-                Py_DECREF(expecting);
-                return -1;
-            }
-            Py_DECREF(unused);
-        }
-    }
-
-    // Discard fields from 'expecting' that default to None
-    PyObject *field_types = NULL;
-    if (PyObject_GetOptionalAttr((PyObject*)Py_TYPE(self),
-                                 &_Py_ID(_field_types),
-                                 &field_types) < 0)
-    {
-        Py_DECREF(expecting);
-        return -1;
-    }
-    if (field_types != NULL) {
-        Py_ssize_t pos = 0;
-        PyObject *field_name, *field_type;
-        while (PyDict_Next(field_types, &pos, &field_name, &field_type)) {
-            if (_PyUnion_Check(field_type)) {
-                // optional field
-                if (PySet_Discard(expecting, field_name) < 0) {
-                    Py_DECREF(expecting);
-                    Py_DECREF(field_types);
-                    return -1;
-                }
-            }
-        }
-        Py_DECREF(field_types);
-    }
-
-    // Now 'expecting' contains the fields or attributes
-    // that would not be filled inside ast_type_replace().
-    Py_ssize_t m = PySet_GET_SIZE(expecting);
-    if (m > 0) {
-        PyObject *names = PyList_New(m);
-        if (names == NULL) {
-            Py_DECREF(expecting);
-            return -1;
-        }
-        Py_ssize_t i = 0, pos = 0;
-        PyObject *item;
-        Py_hash_t hash;
-        while (_PySet_NextEntry(expecting, &pos, &item, &hash)) {
-            PyObject *name = PyObject_Repr(item);
-            if (name == NULL) {
-                Py_DECREF(expecting);
-                Py_DECREF(names);
-                return -1;
-            }
-            // steal the reference 'name'
-            PyList_SET_ITEM(names, i++, name);
-        }
-        Py_DECREF(expecting);
-        if (PyList_Sort(names) < 0) {
-            Py_DECREF(names);
-            return -1;
-        }
-        PyObject *sep = PyUnicode_FromString(", ");
-        if (sep == NULL) {
-            Py_DECREF(names);
-            return -1;
-        }
-        PyObject *str_names = PyUnicode_Join(sep, names);
-        Py_DECREF(sep);
-        Py_DECREF(names);
-        if (str_names == NULL) {
-            return -1;
-        }
-        PyErr_Format(PyExc_TypeError,
-                     "%.400s.__replace__ missing %ld keyword argument%s: %U.",
-                     Py_TYPE(self)->tp_name, m, m == 1 ? "" : "s", str_names);
-        Py_DECREF(str_names);
-        return -1;
-    }
-    else {
-        Py_DECREF(expecting);
-        return 1;
-    }
-}
-
 /*
  * Python equivalent:
  *
@@ -1477,9 +1301,6 @@ def visitModule(self, mod):
     if (PyObject_GetOptionalAttr(self, state->__dict__, &dict) < 0) {
         goto cleanup;
     }
-    if (ast_type_replace_check(self, dict, fields, attributes, kwargs) < 0) {
-        goto cleanup;
-    }
     empty_tuple = PyTuple_New(0);
     if (empty_tuple == NULL) {
         goto cleanup;
diff --git a/Python/Python-ast.c b/Python/Python-ast.c
