Fix #323: Support Python 3.12

.github/workflows/tests.yml

@@ -25,11 +25,14 @@ jobs:
     runs-on: ${{ matrix.os }}
     strategy:
       matrix:
-        python-version: [3.5, 3.6, 3.7, 3.8, 3.9, "3.10", "3.11"]
+        python-version: [3.5, 3.6, 3.7, 3.8, 3.9, "3.10", "3.11", "3.12-dev"]
         # Jan 2023: We have pinned back from ubuntu-latest (which is
         # now ubuntu 22.04) because older Python versions like
         # 3.5, 3.6 and presumably 2.7 are not available in it.
         os: [ubuntu-20.04, macos-latest]
+        exclude:
+          - os: macos-latest
+            python-version: 3.12-dev
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python
@@ -77,6 +80,7 @@ jobs:
         path: dist/*whl
     - name: Test
       run: |
+        python -VV
         python -c 'import greenlet._greenlet as G; assert G.GREENLET_USE_STANDARD_THREADING'
         python -m unittest discover -v greenlet.tests
     - name: Doctest

CHANGES.rst

@@ -18,6 +18,11 @@
   compilers for some time. See `PR 347
   <https://github.com/python-greenlet/greenlet/pull/347>`_ from Khem
   Raj.
+- Add initial support for Python 3.12. See `issue
+  <https://github.com/python-greenlet/greenlet/issues/323>`_ and `PR
+  <https://github.com/python-greenlet/greenlet/pull/327>`_; thanks go
+  to (at least) Michael Droettboom, Andreas Motl, Thomas A Caswell,
+  raphaelauv, Hugo van Kemenade, Mark Shannon, and Petr Viktorin.
 
 
 2.0.2 (2023-01-28)

src/greenlet/greenlet.cpp

@@ -3095,7 +3095,12 @@ static PyObject*
 mod_get_tstate_trash_delete_nesting(PyObject* UNUSED(module))
 {
     PyThreadState* tstate = PyThreadState_GET();
+
+#if GREENLET_PY312
+    return PyLong_FromLong(tstate->trash.delete_nesting);
+#else
     return PyLong_FromLong(tstate->trash_delete_nesting);
+#endif
 }
 
 static PyMethodDef GreenMethods[] = {

src/greenlet/greenlet_cpython_compat.hpp

@@ -48,6 +48,12 @@ We have to save and restore this as well.
 #    define GREENLET_USE_CFRAME 0
 #endif
 
+#if PY_VERSION_HEX >= 0x30C0000
+#    define GREENLET_PY312 1
+#else
+#    define GREENLET_PY312 0
+#endif
+
 #if PY_VERSION_HEX >= 0x30B00A4
 /*
 Greenlet won't compile on anything older than Python 3.11 alpha 4 (see

src/greenlet/greenlet_greenlet.hpp

@@ -143,7 +143,12 @@ namespace greenlet
         _PyCFrame* cframe;
         int use_tracing;
 #endif
+#if GREENLET_PY312
+        int py_recursion_depth;
+        int c_recursion_depth;
+#else
         int recursion_depth;
+#endif
         int trash_delete_nesting;
 #if GREENLET_PY311
         _PyInterpreterFrame* current_frame;
@@ -748,7 +753,12 @@ PythonState::PythonState()
     ,cframe(nullptr)
     ,use_tracing(0)
 #endif
+#if GREENLET_PY312
+    ,py_recursion_depth(0)
+    ,c_recursion_depth(0)
+#else
     ,recursion_depth(0)
+#endif
     ,trash_delete_nesting(0)
 #if GREENLET_PY311
     ,current_frame(nullptr)
@@ -828,24 +838,34 @@ void PythonState::operator<<(const PyThreadState *const tstate) G_NOEXCEPT
       the switch, use `will_switch_from`.
     */
     this->cframe = tstate->cframe;
+    #if !GREENLET_PY312
     this->use_tracing = tstate->cframe->use_tracing;
+    #endif
 #endif
 #if GREENLET_PY311
+    #if GREENLET_PY312
+    this->py_recursion_depth = tstate->py_recursion_limit - tstate->py_recursion_remaining;
+    this->c_recursion_depth = C_RECURSION_LIMIT - tstate->c_recursion_remaining;
+    #else
     this->recursion_depth = tstate->recursion_limit - tstate->recursion_remaining;
+    #endif
     this->current_frame = tstate->cframe->current_frame;
     this->datastack_chunk = tstate->datastack_chunk;
     this->datastack_top = tstate->datastack_top;
     this->datastack_limit = tstate->datastack_limit;
     PyFrameObject *frame = PyThreadState_GetFrame((PyThreadState *)tstate);
     Py_XDECREF(frame);  // PyThreadState_GetFrame gives us a new reference.
     this->_top_frame.steal(frame);
+    #if GREENLET_PY312
+    this->trash_delete_nesting = tstate->trash.delete_nesting;
+    #else
+    this->trash_delete_nesting = tstate->trash_delete_nesting;
+    #endif
 #else
     this->recursion_depth = tstate->recursion_depth;
     this->_top_frame.steal(tstate->frame);
-#endif
-
-    // All versions of Python.
     this->trash_delete_nesting = tstate->trash_delete_nesting;
+#endif
 }
 
 void PythonState::operator>>(PyThreadState *const tstate) G_NOEXCEPT
@@ -864,26 +884,37 @@ void PythonState::operator>>(PyThreadState *const tstate) G_NOEXCEPT
       root_cframe here. See note above about why we can't
       just copy this from ``origin->cframe->use_tracing``.
     */
+    #if !GREENLET_PY312
     tstate->cframe->use_tracing = this->use_tracing;
+    #endif
 #endif
 #if GREENLET_PY311
+    #if GREENLET_PY312
+    tstate->py_recursion_remaining = tstate->py_recursion_limit - this->py_recursion_depth;
+    tstate->c_recursion_remaining = C_RECURSION_LIMIT - this->c_recursion_depth;
+    #else
     tstate->recursion_remaining = tstate->recursion_limit - this->recursion_depth;
+    #endif
     tstate->cframe->current_frame = this->current_frame;
     tstate->datastack_chunk = this->datastack_chunk;
     tstate->datastack_top = this->datastack_top;
     tstate->datastack_limit = this->datastack_limit;
     this->_top_frame.relinquish_ownership();
+    #if GREENLET_PY312
+    tstate->trash.delete_nesting = this->trash_delete_nesting;
+    #else
+    tstate->trash_delete_nesting = this->trash_delete_nesting;
+    #endif
 #else
     tstate->frame = this->_top_frame.relinquish_ownership();
     tstate->recursion_depth = this->recursion_depth;
-#endif
-    // All versions of Python.
     tstate->trash_delete_nesting = this->trash_delete_nesting;
+#endif
 }
 
 void PythonState::will_switch_from(PyThreadState *const origin_tstate) G_NOEXCEPT
 {
-#if GREENLET_USE_CFRAME
+#if GREENLET_USE_CFRAME && !GREENLET_PY312
     // The weird thing is, we don't actually save this for an
     // effect on the current greenlet, it's saved for an
     // effect on the target greenlet. That is, we want
@@ -895,7 +926,10 @@ void PythonState::will_switch_from(PyThreadState *const origin_tstate) G_NOEXCEP
 void PythonState::set_initial_state(const PyThreadState* const tstate) G_NOEXCEPT
 {
     this->_top_frame = nullptr;
-#if GREENLET_PY311
+#if GREENLET_PY312
+    this->py_recursion_depth = tstate->py_recursion_limit - tstate->py_recursion_remaining;
+    this->c_recursion_depth = tstate->py_recursion_limit - tstate->py_recursion_remaining;
+#elif GREENLET_PY311
     this->recursion_depth = tstate->recursion_limit - tstate->recursion_remaining;
 #else
     this->recursion_depth = tstate->recursion_depth;