gh-117398: Use Per-Interpreter State for the _datetime Static Types (gh-119929)

We make use of the same mechanism that we use for the static builtin types.  This required a few tweaks.

The relevant code could use some cleanup but I opted to avoid the significant churn in this change.  I'll tackle that separately.

This change is the final piece needed to make _datetime support multiple interpreters.  I've updated the module slot accordingly.

Author: ericsnowcurrently

Include/internal/pycore_object.h

@@ -589,7 +589,7 @@ _PyObject_GET_WEAKREFS_LISTPTR(PyObject *op)
     if (PyType_Check(op) &&
             ((PyTypeObject *)op)->tp_flags & _Py_TPFLAGS_STATIC_BUILTIN) {
         PyInterpreterState *interp = _PyInterpreterState_GET();
-        static_builtin_state *state = _PyStaticType_GetState(
+        managed_static_type_state *state = _PyStaticType_GetState(
                                                 interp, (PyTypeObject *)op);
         return _PyStaticType_GET_WEAKREFS_LISTPTR(state);
     }

Include/internal/pycore_typeobject.h

@@ -44,10 +44,12 @@ struct type_cache {
 
 /* For now we hard-code this to a value for which we are confident
    all the static builtin types will fit (for all builds). */
-#define _Py_MAX_STATIC_BUILTIN_TYPES 200
+#define _Py_MAX_MANAGED_STATIC_BUILTIN_TYPES 200
+#define _Py_MAX_MANAGED_STATIC_EXT_TYPES 10
 
 typedef struct {
     PyTypeObject *type;
+    int isbuiltin;
     int readying;
     int ready;
     // XXX tp_dict can probably be statically allocated,
@@ -59,7 +61,7 @@ typedef struct {
        are also some diagnostic uses for the list of weakrefs,
        so we still keep it. */
     PyObject *tp_weaklist;
-} static_builtin_state;
+} managed_static_type_state;
 
 struct types_state {
     /* Used to set PyTypeObject.tp_version_tag.
@@ -105,8 +107,16 @@ struct types_state {
        num_builtins_initialized is incremented once for each static
        builtin type.  Once initialization is over for a subinterpreter,
        the value will be the same as for all other interpreters.  */
-    size_t num_builtins_initialized;
-    static_builtin_state builtins[_Py_MAX_STATIC_BUILTIN_TYPES];
+    struct {
+        size_t num_initialized;
+        managed_static_type_state initialized[_Py_MAX_MANAGED_STATIC_BUILTIN_TYPES];
+    } builtins;
+    /* We apply a similar strategy for managed extension modules. */
+    struct {
+        size_t num_initialized;
+        size_t next_index;
+        managed_static_type_state initialized[_Py_MAX_MANAGED_STATIC_EXT_TYPES];
+    } for_extensions;
     PyMutex mutex;
 };
 
@@ -130,12 +140,35 @@ typedef struct wrapperbase pytype_slotdef;
 
 
 static inline PyObject **
-_PyStaticType_GET_WEAKREFS_LISTPTR(static_builtin_state *state)
+_PyStaticType_GET_WEAKREFS_LISTPTR(managed_static_type_state *state)
 {
     assert(state != NULL);
     return &state->tp_weaklist;
 }
 
+extern int _PyStaticType_InitBuiltin(
+    PyInterpreterState *interp,
+    PyTypeObject *type);
+extern void _PyStaticType_FiniBuiltin(
+    PyInterpreterState *interp,
+    PyTypeObject *type);
+extern void _PyStaticType_ClearWeakRefs(
+    PyInterpreterState *interp,
+    PyTypeObject *type);
+extern managed_static_type_state * _PyStaticType_GetState(
+    PyInterpreterState *interp,
+    PyTypeObject *type);
+
+// Export for '_datetime' shared extension.
+PyAPI_FUNC(int) _PyStaticType_InitForExtension(
+    PyInterpreterState *interp,
+     PyTypeObject *self);
+PyAPI_FUNC(void) _PyStaticType_FiniForExtension(
+    PyInterpreterState *interp,
+     PyTypeObject *self,
+     int final);
+
+
 /* Like PyType_GetModuleState, but skips verification
  * that type is a heap type with an associated module */
 static inline void *
@@ -151,11 +184,6 @@ _PyType_GetModuleState(PyTypeObject *type)
 }
 
 
-extern int _PyStaticType_InitBuiltin(PyInterpreterState *, PyTypeObject *type);
-extern static_builtin_state * _PyStaticType_GetState(PyInterpreterState *, PyTypeObject *);
-extern void _PyStaticType_ClearWeakRefs(PyInterpreterState *, PyTypeObject *type);
-extern void _PyStaticType_Dealloc(PyInterpreterState *, PyTypeObject *);
-
 // Export for 'math' shared extension, used via _PyType_IsReady() static inline
 // function
 PyAPI_FUNC(PyObject *) _PyType_GetDict(PyTypeObject *);

Misc/NEWS.d/next/Library/2024-06-01-16-58-43.gh-issue-117398.kR0RW7.rst

@@ -0,0 +1,2 @@
+The ``_datetime`` module (C implementation for :mod:`datetime`) now supports
+being imported in multiple interpreters.