bpo-47168: List feature macros in the stable ABI manifest, improve tests

Misc/stable_abi.txt

@@ -29,6 +29,8 @@
 #   value may change.
 # - typedef: A C typedef which is used in other definitions in the limited API.
 #   Its size/layout/signature must not change.
+# - ifdef: A feature macro: other items may be conditional on whether the macro
+#   is defined or not.
 
 # Each top-level item can have details defined below it:
 # - added: The version in which the item was added to the stable ABI.
@@ -41,6 +43,10 @@
 #     of the stable ABI.
 #   - a combination of the above (functions that were called by macros that
 #     were public in the past)
+# - doc: for `ifdef`, the blurb added in documentation
+# - windows: for `ifdef`, this macro is defined on Windows. (This info is used
+#   to generate the DLL manifest and needs to be available on all platforms.)
+#   `maybe` marks macros defined on some but not all Windows builds.
 
 # For structs, one of the following must be set:
 # - opaque: The struct name is available in the Limited API, but its members
@@ -59,6 +65,24 @@
 #    https://docs.python.org/3/c-api/stable.html#stable
 
 
+# Feature macros for optional functionality:
+
+ifdef MS_WINDOWS
+    doc on Windows
+    windows
+ifdef HAVE_FORK
+    doc on platforms with fork()
+ifdef USE_STACKCHECK
+    doc on platforms with USE_STACKCHECK
+    windows maybe
+ifdef PY_HAVE_THREAD_NATIVE_ID
+    doc on platforms with native thread IDs
+    windows
+ifdef Py_REF_DEBUG
+    doc when Python is compiled in debug mode (with Py_REF_DEBUG)
+    windows maybe
+
+
 # Mentioned in PEP 384:
 
 struct PyObject

Modules/_testcapi_feature_macros.inc

@@ -0,0 +1,49 @@
+// Generated by Tools/scripts/stable_abi.py
+
+// Add an entry in dict `result` for each Stable ABI feature macro.
+
+#ifdef HAVE_FORK
+    res = PyDict_SetItemString(result, "HAVE_FORK", Py_True);
+#else
+    res = PyDict_SetItemString(result, "HAVE_FORK", Py_False);
+#endif
+if (res) {
+    Py_DECREF(result); return NULL;
+}
+
+#ifdef MS_WINDOWS
+    res = PyDict_SetItemString(result, "MS_WINDOWS", Py_True);
+#else
+    res = PyDict_SetItemString(result, "MS_WINDOWS", Py_False);
+#endif
+if (res) {
+    Py_DECREF(result); return NULL;
+}
+
+#ifdef PY_HAVE_THREAD_NATIVE_ID
+    res = PyDict_SetItemString(result, "PY_HAVE_THREAD_NATIVE_ID", Py_True);
+#else
+    res = PyDict_SetItemString(result, "PY_HAVE_THREAD_NATIVE_ID", Py_False);
+#endif
+if (res) {
+    Py_DECREF(result); return NULL;
+}
+
+#ifdef Py_REF_DEBUG
+    res = PyDict_SetItemString(result, "Py_REF_DEBUG", Py_True);
+#else
+    res = PyDict_SetItemString(result, "Py_REF_DEBUG", Py_False);
+#endif
+if (res) {
+    Py_DECREF(result); return NULL;
+}
+
+#ifdef USE_STACKCHECK
+    res = PyDict_SetItemString(result, "USE_STACKCHECK", Py_True);
+#else
+    res = PyDict_SetItemString(result, "USE_STACKCHECK", Py_False);
+#endif
+if (res) {
+    Py_DECREF(result); return NULL;
+}
+

Modules/_testcapimodule.c

@@ -5919,6 +5919,18 @@ frame_getlasti(PyObject *self, PyObject *frame)
     return PyLong_FromLong(lasti);
 }
 
+static PyObject *
+get_feature_macros(PyObject *self, PyObject *Py_UNUSED(args))
+{
+    PyObject *result = PyDict_New();
+    if (!result) {
+        return NULL;
+    }
+    int res;
+#include "_testcapi_feature_macros.inc"
+    return result;
+}
+
 
 static PyObject *negative_dictoffset(PyObject *, PyObject *);
 static PyObject *test_buildvalue_issue38913(PyObject *, PyObject *);
@@ -6214,6 +6226,7 @@ static PyMethodDef TestMethods[] = {
     {"frame_getgenerator", frame_getgenerator, METH_O, NULL},
     {"frame_getbuiltins", frame_getbuiltins, METH_O, NULL},
     {"frame_getlasti", frame_getlasti, METH_O, NULL},
+    {"get_feature_macros", get_feature_macros, METH_NOARGS, NULL},
     {NULL, NULL} /* sentinel */
 };