Add Python 3.11 beta 3 support

Co-Authored-By: Petr Viktorin <encukou@gmail.com>

_setuputils.py

@@ -244,6 +244,9 @@ def cythonize1(ext):
                 'infer_types': True,
                 'nonecheck': False,
             },
+            compile_time_env={
+                'PY39B1': sys.hexversion >= 0x030900B1,
+            },
             # The common_utility_include_dir (not well documented)
             # causes Cython to emit separate files for much of the
             # static support code. Each of the modules then includes

src/gevent/_gevent_cgreenlet.pxd

@@ -52,35 +52,48 @@ cdef inline void greenlet_init():
         PyGreenlet_Import()
         _greenlet_imported = True
 
-cdef extern from "Python.h":
+ctypedef object CodeType
 
-    ctypedef class types.CodeType [object PyCodeObject]:
-        pass
+IF PY39B1:
+    ctypedef object FrameType
 
-cdef extern from "frameobject.h":
+    cdef extern from "Python.h":
+        CodeType PyFrame_GetCode(FrameType frame)
+        void* PyFrame_GetBack(FrameType frame)
+
+ELSE:
+    cdef extern from "frameobject.h":
+        ctypedef class types.FrameType [object PyFrameObject]:
+            # We don't have PyFrame_GetCode, need to use the pointer directly
+            cdef CodeType f_code
 
-    ctypedef class types.FrameType [object PyFrameObject]:
-        cdef CodeType f_code
-        # Accessing the f_lineno directly doesn't work. There is an accessor
-        # function, PyFrame_GetLineNumber that is needed to turn the raw line number
-        # into the executing line number.
-        # cdef int f_lineno
-        # We can't declare this in the object as an object, because it's
-        # allowed to be NULL, and Cython can't handle that.
-        # We have to go through the python machinery to get a
-        # proper None instead, or use an inline function.
-        cdef void* f_back
+            # We can't declare this in the object as an object, because it's
+            # allowed to be NULL, and Cython can't handle that.
+            # We have to go through the python machinery to get a
+            # proper None instead, or use a function.
+            cdef void* f_back
 
+cdef extern from "frameobject.h":
     int PyFrame_GetLineNumber(FrameType frame)
 
 @cython.nonecheck(False)
 cdef inline FrameType get_f_back(FrameType frame):
-    if frame.f_back != NULL:
-        return <FrameType>frame.f_back
+    IF PY39B1:
+        f_back = PyFrame_GetBack(frame)
+    ELSE:
+        f_back = frame.f_back
+    if f_back != NULL:
+        return <FrameType>f_back
 
 cdef inline int get_f_lineno(FrameType frame):
     return PyFrame_GetLineNumber(frame)
 
+cdef inline CodeType get_f_code(FrameType frame):
+    IF PY39B1:
+        return PyFrame_GetCode(frame)
+    ELSE:
+        return frame.f_code
+
 cdef void _init()
 
 cdef class SpawnedLink:

src/gevent/greenlet.py

@@ -58,6 +58,7 @@ locals()['get_generic_parent'] = lambda s: s.parent
 # Frame access
 locals()['get_f_back'] = lambda frame: frame.f_back
 locals()['get_f_lineno'] = lambda frame: frame.f_lineno
+locals()['get_f_code'] = lambda frame: frame.f_code
 
 if _PYPY:
     import _continuation # pylint:disable=import-error
@@ -157,7 +158,7 @@ def _extract_stack(limit):
         # Arguments are always passed to the constructor as Python objects,
         # meaning we wind up boxing the f_lineno just to unbox it if we pass it.
         # It's faster to simply assign once the object is created.
-        older_Frame.f_code = frame.f_code
+        older_Frame.f_code = get_f_code(frame)
         older_Frame.f_lineno = get_f_lineno(frame) # pylint:disable=undefined-variable
         if newer_Frame is not None:
             newer_Frame.f_back = older_Frame