bpo-36737: Use the module state C-API for warnings. (gh-13159)

Include/internal/pycore_pylifecycle.h

@@ -81,7 +81,7 @@ extern void PyLong_Fini(void);
 extern void _PyFaulthandler_Fini(void);
 extern void _PyHash_Fini(void);
 extern int _PyTraceMalloc_Fini(void);
-extern void _PyWarnings_Fini(_PyRuntimeState *runtime);
+extern void _PyWarnings_Fini(PyInterpreterState *interp);
 
 extern void _PyGILState_Init(
     _PyRuntimeState *runtime,

Include/internal/pycore_pystate.h

@@ -90,6 +90,8 @@ struct _is {
     PyObject *pyexitmodule;
 
     uint64_t tstate_next_unique_id;
+
+    struct _warnings_runtime_state warnings;
 };
 
 PyAPI_FUNC(struct _is*) _PyInterpreterState_LookUpID(PY_INT64_T);
@@ -179,7 +181,6 @@ typedef struct pyruntimestate {
     int nexitfuncs;
 
     struct _gc_runtime_state gc;
-    struct _warnings_runtime_state warnings;
     struct _ceval_runtime_state ceval;
     struct _gilstate_runtime_state gilstate;
 

Misc/NEWS.d/next/Core and Builtins/2019-05-07-12-18-11.bpo-36737.XAo6LY.rst

+Move PyRuntimeState.warnings into per-interpreter state (via "module
+state").

Python/pylifecycle.c

@@ -1288,7 +1288,7 @@ Py_FinalizeEx(void)
     PyDict_Fini();
     PySlice_Fini();
     _PyGC_Fini(runtime);
-    _PyWarnings_Fini(runtime);
+    _PyWarnings_Fini(interp);
     _Py_HashRandomization_Fini();
     _PyArg_Fini();
     PyAsyncGen_Fini();

Python/pystate.c

@@ -5,6 +5,7 @@
 #include "pycore_coreconfig.h"
 #include "pycore_pymem.h"
 #include "pycore_pystate.h"
+#include "pycore_pylifecycle.h"
 
 /* --------------------------------------------------------------------------
 CAUTION
@@ -257,6 +258,9 @@ _PyInterpreterState_Clear(_PyRuntimeState *runtime, PyInterpreterState *interp)
     Py_CLEAR(interp->after_forkers_parent);
     Py_CLEAR(interp->after_forkers_child);
 #endif
+    if (runtime->finalizing == NULL) {
+        _PyWarnings_Fini(interp);
+    }
     // XXX Once we have one allocator per interpreter (i.e.
     // per-interpreter GC) we must ensure that all of the interpreter's
     // objects have been cleaned up at the point.