From dcc54215ac1eb4b6fab2a9ffe1abcdf3ac4bb77e Mon Sep 17 00:00:00 2001
From: Serhiy Storchaka <storchaka@gmail.com>
Date: Mon, 5 Oct 2020 12:32:00 +0300
Subject: [PATCH] bpo-41936. Remove macros
 Py_ALLOW_RECURSION/Py_END_ALLOW_RECURSION (GH-22552)

---
 Doc/whatsnew/3.10.rst                                     | 5 +++++
 Include/ceval.h                                           | 8 --------
 Include/cpython/pystate.h                                 | 2 --
 .../next/C API/2020-10-05-01-25-23.bpo-41936.1gb5ra.rst   | 3 +++
 Python/ceval.c                                            | 3 ---
 Python/pystate.c                                          | 1 -
 6 files changed, 8 insertions(+), 14 deletions(-)
 create mode 100644 Misc/NEWS.d/next/C API/2020-10-05-01-25-23.bpo-41936.1gb5ra.rst

diff --git a/Doc/whatsnew/3.10.rst b/Doc/whatsnew/3.10.rst
index 9c3a0287d55..1ea5aeac8a3 100644
--- a/Doc/whatsnew/3.10.rst
+++ b/Doc/whatsnew/3.10.rst
@@ -365,3 +365,8 @@ Removed
 * Removed ``_Py_CheckRecursionLimit`` variable: it has been replaced by
   ``ceval.recursion_limit`` of the :c:type:`PyInterpreterState` structure.
   (Contributed by Victor Stinner in :issue:`41834`.)
+
+* Removed undocumented macros ``Py_ALLOW_RECURSION`` and
+  ``Py_END_ALLOW_RECURSION`` and the ``recursion_critical`` field of the
+  :c:type:`PyInterpreterState` structure.
+  (Contributed by Serhiy Storchaka in :issue:`41936`.)
diff --git a/Include/ceval.h b/Include/ceval.h
index 0f372e2044a..0f687666e2b 100644
--- a/Include/ceval.h
+++ b/Include/ceval.h
@@ -67,14 +67,6 @@ PyAPI_FUNC(int) Py_GetRecursionLimit(void);
 PyAPI_FUNC(int) Py_EnterRecursiveCall(const char *where);
 PyAPI_FUNC(void) Py_LeaveRecursiveCall(void);
 
-#define Py_ALLOW_RECURSION \
-  do { unsigned char _old = PyThreadState_GET()->recursion_critical;\
-    PyThreadState_GET()->recursion_critical = 1;
-
-#define Py_END_ALLOW_RECURSION \
-    PyThreadState_GET()->recursion_critical = _old; \
-  } while(0);
-
 PyAPI_FUNC(const char *) PyEval_GetFuncName(PyObject *);
 PyAPI_FUNC(const char *) PyEval_GetFuncDesc(PyObject *);
 
diff --git a/Include/cpython/pystate.h b/Include/cpython/pystate.h
index 42a7fc16306..5d5e4e33197 100644
--- a/Include/cpython/pystate.h
+++ b/Include/cpython/pystate.h
@@ -56,8 +56,6 @@ struct _ts {
     int recursion_depth;
     char overflowed; /* The stack has overflowed. Allow 50 more calls
                         to handle the runtime error. */
-    char recursion_critical; /* The current calls must not cause
-                                a stack overflow. */
     int stackcheck_counter;
 
     /* 'tracing' keeps track of the execution depth when tracing/profiling.
diff --git a/Misc/NEWS.d/next/C API/2020-10-05-01-25-23.bpo-41936.1gb5ra.rst b/Misc/NEWS.d/next/C API/2020-10-05-01-25-23.bpo-41936.1gb5ra.rst
new file mode 100644
index 00000000000..64613533086
--- /dev/null
+++ b/Misc/NEWS.d/next/C API/2020-10-05-01-25-23.bpo-41936.1gb5ra.rst	
@@ -0,0 +1,3 @@
+Removed undocumented macros ``Py_ALLOW_RECURSION`` and
+``Py_END_ALLOW_RECURSION`` and the ``recursion_critical`` field of the
+:c:type:`PyInterpreterState` structure.
diff --git a/Python/ceval.c b/Python/ceval.c
index 7c6cf83bc9a..500c588e3c2 100644
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -814,9 +814,6 @@ _Py_CheckRecursiveCall(PyThreadState *tstate, const char *where)
         return -1;
     }
 #endif
-    if (tstate->recursion_critical)
-        /* Somebody asked that we don't check for recursion. */
-        return 0;
     if (tstate->overflowed) {
         if (tstate->recursion_depth > recursion_limit + 50) {
             /* Overflowing while handling an overflow. Give up. */
diff --git a/Python/pystate.c b/Python/pystate.c
index f6d1956e9dc..eb24f2b8006 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -581,7 +581,6 @@ new_threadstate(PyInterpreterState *interp, int init)
     tstate->frame = NULL;
     tstate->recursion_depth = 0;
     tstate->overflowed = 0;
-    tstate->recursion_critical = 0;
     tstate->stackcheck_counter = 0;
     tstate->tracing = 0;
     tstate->use_tracing = 0;