[Python-checkins] bpo-38787: Add PyCFunction_CheckExact() macro for exact type checks (GH-20024)

[scoder]

https://github.com/python/cpython/commit/4c9ea093cd752a6687864674d34250653653f743
commit: 4c9ea093cd752a6687864674d34250653653f743
branch: master
author: scoder <stefan_ml at behnel.de>
committer: GitHub <noreply at github.com>
date: 2020-05-12T07:12:41-07:00
summary:

bpo-38787: Add PyCFunction_CheckExact() macro for exact type checks (GH-20024)



… now that we allow subtypes of PyCFunction.

Also add PyCMethod_CheckExact() and PyCMethod_Check() for checks against the PyCMethod subtype.

files:
A Misc/NEWS.d/next/C API/2020-05-10-16-39-08.bpo-38787.XzQ59O.rst
M Include/cpython/methodobject.h
M Include/methodobject.h
M Objects/abstract.c
M Python/ceval.c

diff --git a/Include/cpython/methodobject.h b/Include/cpython/methodobject.h
index 2ac2cbf36aa79..7ecbfe3b5e2fe 100644
--- a/Include/cpython/methodobject.h
+++ b/Include/cpython/methodobject.h
@@ -4,6 +4,9 @@
 
 PyAPI_DATA(PyTypeObject) PyCMethod_Type;
 
+#define PyCMethod_CheckExact(op) Py_IS_TYPE(op, &PyCMethod_Type)
+#define PyCMethod_Check(op) PyObject_TypeCheck(op, &PyCMethod_Type)
+
 /* Macros for direct access to these values. Type checks are *not*
    done, so use with care. */
 #define PyCFunction_GET_FUNCTION(func) \
diff --git a/Include/methodobject.h b/Include/methodobject.h
index 7c7362cded35b..12e049b4043ba 100644
--- a/Include/methodobject.h
+++ b/Include/methodobject.h
@@ -13,7 +13,8 @@ extern "C" {
 
 PyAPI_DATA(PyTypeObject) PyCFunction_Type;
 
-#define PyCFunction_Check(op) (Py_IS_TYPE(op, &PyCFunction_Type) || (PyType_IsSubtype(Py_TYPE(op), &PyCFunction_Type)))
+#define PyCFunction_CheckExact(op) Py_IS_TYPE(op, &PyCFunction_Type)
+#define PyCFunction_Check(op) PyObject_TypeCheck(op, &PyCFunction_Type)
 
 typedef PyObject *(*PyCFunction)(PyObject *, PyObject *);
 typedef PyObject *(*_PyCFunctionFast) (PyObject *, PyObject *const *, Py_ssize_t);
diff --git a/Misc/NEWS.d/next/C API/2020-05-10-16-39-08.bpo-38787.XzQ59O.rst b/Misc/NEWS.d/next/C API/2020-05-10-16-39-08.bpo-38787.XzQ59O.rst
new file mode 100644
index 0000000000000..f80be666c1c20
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2020-05-10-16-39-08.bpo-38787.XzQ59O.rst	
@@ -0,0 +1,2 @@
+Add PyCFunction_CheckExact() macro for exact type checks now that we allow subtypes of PyCFunction,
+as well as PyCMethod_CheckExact() and PyCMethod_Check() for the new PyCMethod subtype.
diff --git a/Objects/abstract.c b/Objects/abstract.c
index b014f79e8d0fb..5b85b014bd22e 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -900,7 +900,7 @@ binary_op(PyObject *v, PyObject *w, const int op_slot, const char *op_name)
         Py_DECREF(result);
 
         if (op_slot == NB_SLOT(nb_rshift) &&
-            PyCFunction_Check(v) &&
+            PyCFunction_CheckExact(v) &&
             strcmp(((PyCFunctionObject *)v)->m_ml->ml_name, "print") == 0)
         {
             PyErr_Format(PyExc_TypeError,
diff --git a/Python/ceval.c b/Python/ceval.c
index e54e344a5fd51..699ad86a365b1 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -5054,7 +5054,7 @@ trace_call_function(PyThreadState *tstate,
                     PyObject *kwnames)
 {
     PyObject *x;
-    if (PyCFunction_Check(func)) {
+    if (PyCFunction_CheckExact(func) || PyCMethod_CheckExact(func)) {
         C_TRACE(x, PyObject_Vectorcall(func, args, nargs, kwnames));
         return x;
     }
@@ -5115,7 +5115,7 @@ do_call_core(PyThreadState *tstate, PyObject *func, PyObject *callargs, PyObject
 {
     PyObject *result;
 
-    if (PyCFunction_Check(func)) {
+    if (PyCFunction_CheckExact(func) || PyCMethod_CheckExact(func)) {
         C_TRACE(result, PyObject_Call(func, callargs, kwdict));
         return result;
     }