[3.13] gh-117398: Statically Allocate the Datetime C-API (GH-119472) (gh-119641)

This is a backport of 3 commits that go together.

(cherry picked from commit a895756)
(cherry picked from commit b30d30c)
(cherry picked from commit a89fc26)

1 files changed, 188 insertions, 110 deletions

diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index 8164715..8339c98 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -25,24 +25,15 @@
 #  include <winsock2.h>         /* struct timeval */
 #endif
 
-#define PyDate_Check(op) PyObject_TypeCheck(op, &PyDateTime_DateType)
-#define PyDate_CheckExact(op) Py_IS_TYPE(op, &PyDateTime_DateType)
-
-#define PyDateTime_Check(op) PyObject_TypeCheck(op, &PyDateTime_DateTimeType)
-#define PyDateTime_CheckExact(op) Py_IS_TYPE(op, &PyDateTime_DateTimeType)
-
-#define PyTime_Check(op) PyObject_TypeCheck(op, &PyDateTime_TimeType)
-#define PyTime_CheckExact(op) Py_IS_TYPE(op, &PyDateTime_TimeType)
-
-#define PyDelta_Check(op) PyObject_TypeCheck(op, &PyDateTime_DeltaType)
-#define PyDelta_CheckExact(op) Py_IS_TYPE(op, &PyDateTime_DeltaType)
-
-#define PyTZInfo_Check(op) PyObject_TypeCheck(op, &PyDateTime_TZInfoType)
-#define PyTZInfo_CheckExact(op) Py_IS_TYPE(op, &PyDateTime_TZInfoType)
-
-#define PyTimezone_Check(op) PyObject_TypeCheck(op, &PyDateTime_TimeZoneType)
-
 typedef struct {
+    PyTypeObject *date_type;
+    PyTypeObject *datetime_type;
+    PyTypeObject *delta_type;
+    PyTypeObject *isocalendar_date_type;
+    PyTypeObject *time_type;
+    PyTypeObject *tzinfo_type;
+    PyTypeObject *timezone_type;
+
     /* Conversion factors. */
     PyObject *us_per_ms;       // 1_000
     PyObject *us_per_second;   // 1_000_000
@@ -57,11 +48,34 @@ typedef struct {
 
     /* The interned Unix epoch datetime instance */
     PyObject *epoch;
+
+    /* While we use a global state, we ensure it's only initialized once */
+    int initialized;
 } datetime_state;
 
 static datetime_state _datetime_global_state;
 
-#define STATIC_STATE() (&_datetime_global_state)
+static inline datetime_state* get_datetime_state(void)
+{
+    return &_datetime_global_state;
+}
+
+#define PyDate_Check(op) PyObject_TypeCheck(op, get_datetime_state()->date_type)
+#define PyDate_CheckExact(op) Py_IS_TYPE(op, get_datetime_state()->date_type)
+
+#define PyDateTime_Check(op) PyObject_TypeCheck(op, get_datetime_state()->datetime_type)
+#define PyDateTime_CheckExact(op) Py_IS_TYPE(op, get_datetime_state()->datetime_type)
+
+#define PyTime_Check(op) PyObject_TypeCheck(op, get_datetime_state()->time_type)
+#define PyTime_CheckExact(op) Py_IS_TYPE(op, get_datetime_state()->time_type)
+
+#define PyDelta_Check(op) PyObject_TypeCheck(op, get_datetime_state()->delta_type)
+#define PyDelta_CheckExact(op) Py_IS_TYPE(op, get_datetime_state()->delta_type)
+
+#define PyTZInfo_Check(op) PyObject_TypeCheck(op, get_datetime_state()->tzinfo_type)
+#define PyTZInfo_CheckExact(op) Py_IS_TYPE(op, get_datetime_state()->tzinfo_type)
+
+#define PyTimezone_Check(op) PyObject_TypeCheck(op, get_datetime_state()->timezone_type)
 
 /* We require that C int be at least 32 bits, and use int virtually
  * everywhere.  In just a few cases we use a temp long, where a Python
@@ -142,25 +156,16 @@ static datetime_state _datetime_global_state;
  */
 #define MONTH_IS_SANE(M) ((unsigned int)(M) - 1 < 12)
 
-/* Forward declarations. */
-static PyTypeObject PyDateTime_DateType;
-static PyTypeObject PyDateTime_DateTimeType;
-static PyTypeObject PyDateTime_DeltaType;
-static PyTypeObject PyDateTime_IsoCalendarDateType;
-static PyTypeObject PyDateTime_TimeType;
-static PyTypeObject PyDateTime_TZInfoType;
-static PyTypeObject PyDateTime_TimeZoneType;
-
 static int check_tzinfo_subclass(PyObject *p);
 
 /*[clinic input]
 module datetime
-class datetime.datetime "PyDateTime_DateTime *" "&PyDateTime_DateTimeType"
-class datetime.date "PyDateTime_Date *" "&PyDateTime_DateType"
-class datetime.time "PyDateTime_Time *" "&PyDateTime_TimeType"
-class datetime.IsoCalendarDate "PyDateTime_IsoCalendarDate *" "&PyDateTime_IsoCalendarDateType"
+class datetime.datetime "PyDateTime_DateTime *" "get_datetime_state()->datetime_type"
+class datetime.date "PyDateTime_Date *" "get_datetime_state()->date_type"
+class datetime.time "PyDateTime_Time *" "get_datetime_state()->time_type"
+class datetime.IsoCalendarDate "PyDateTime_IsoCalendarDate *" "get_datetime_state()->isocalendar_date_type"
 [clinic start generated code]*/
-/*[clinic end generated code: output=da39a3ee5e6b4b0d input=6f65a48dd22fa40f]*/
+/*[clinic end generated code: output=da39a3ee5e6b4b0d input=c8f3d834a860d50a]*/
 
 #include "clinic/_datetimemodule.c.h"
 
@@ -979,7 +984,7 @@ new_date_ex(int year, int month, int day, PyTypeObject *type)
 }
 
 #define new_date(year, month, day) \
-    new_date_ex(year, month, day, &PyDateTime_DateType)
+    new_date_ex(year, month, day, get_datetime_state()->date_type)
 
 // Forward declaration
 static PyObject *
@@ -989,12 +994,13 @@ new_datetime_ex(int, int, int, int, int, int, int, PyObject *, PyTypeObject *);
 static PyObject *
 new_date_subclass_ex(int year, int month, int day, PyObject *cls)
 {
+    datetime_state *st = get_datetime_state();
     PyObject *result;
     // We have "fast path" constructors for two subclasses: date and datetime
-    if ((PyTypeObject *)cls == &PyDateTime_DateType) {
+    if ((PyTypeObject *)cls == st->date_type) {
         result = new_date_ex(year, month, day, (PyTypeObject *)cls);
     }
-    else if ((PyTypeObject *)cls == &PyDateTime_DateTimeType) {
+    else if ((PyTypeObject *)cls == st->datetime_type) {
         result = new_datetime_ex(year, month, day, 0, 0, 0, 0, Py_None,
                                  (PyTypeObject *)cls);
     }
@@ -1049,7 +1055,7 @@ new_datetime_ex(int year, int month, int day, int hour, int minute,
 
 #define new_datetime(y, m, d, hh, mm, ss, us, tzinfo, fold) \
     new_datetime_ex2(y, m, d, hh, mm, ss, us, tzinfo, fold, \
-                    &PyDateTime_DateTimeType)
+                    get_datetime_state()->datetime_type)
 
 static PyObject *
 call_subclass_fold(PyObject *cls, int fold, const char *format, ...)
@@ -1088,9 +1094,11 @@ Done:
 static PyObject *
 new_datetime_subclass_fold_ex(int year, int month, int day, int hour, int minute,
                               int second, int usecond, PyObject *tzinfo,
-                              int fold, PyObject *cls) {
+                              int fold, PyObject *cls)
+{
+    datetime_state *st = get_datetime_state();
     PyObject* dt;
-    if ((PyTypeObject*)cls == &PyDateTime_DateTimeType) {
+    if ((PyTypeObject*)cls == st->datetime_type) {
         // Use the fast path constructor
         dt = new_datetime(year, month, day, hour, minute, second, usecond,
                           tzinfo, fold);
@@ -1152,14 +1160,15 @@ new_time_ex(int hour, int minute, int second, int usecond,
 }
 
 #define new_time(hh, mm, ss, us, tzinfo, fold)                       \
-    new_time_ex2(hh, mm, ss, us, tzinfo, fold, &PyDateTime_TimeType)
+    new_time_ex2(hh, mm, ss, us, tzinfo, fold, get_datetime_state()->time_type)
 
 static PyObject *
 new_time_subclass_fold_ex(int hour, int minute, int second, int usecond,
                           PyObject *tzinfo, int fold, PyObject *cls)
 {
     PyObject *t;
-    if ((PyTypeObject*)cls == &PyDateTime_TimeType) {
+    datetime_state *st = get_datetime_state();
+    if ((PyTypeObject*)cls == st->time_type) {
         // Use the fast path constructor
         t = new_time(hour, minute, second, usecond, tzinfo, fold);
     }
@@ -1172,6 +1181,8 @@ new_time_subclass_fold_ex(int hour, int minute, int second, int usecond,
     return t;
 }
 
+static PyDateTime_Delta * look_up_delta(int, int, int, PyTypeObject *);
+
 /* Create a timedelta instance.  Normalize the members iff normalize is
  * true.  Passing false is a speed optimization, if you know for sure
  * that seconds and microseconds are already in their proper ranges.  In any
@@ -1192,6 +1203,12 @@ new_delta_ex(int days, int seconds, int microseconds, int normalize,
     if (check_delta_day_range(days) < 0)
         return NULL;
 
+    self = look_up_delta(days, seconds, microseconds, type);
+    if (self != NULL) {
+        return (PyObject *)self;
+    }
+    assert(!PyErr_Occurred());
+
     self = (PyDateTime_Delta *) (type->tp_alloc(type, 0));
     if (self != NULL) {
         self->hashcode = -1;
@@ -1203,7 +1220,7 @@ new_delta_ex(int days, int seconds, int microseconds, int normalize,
 }
 
 #define new_delta(d, s, us, normalize)  \
-    new_delta_ex(d, s, us, normalize, &PyDateTime_DeltaType)
+    new_delta_ex(d, s, us, normalize, get_datetime_state()->delta_type)
 
 
 typedef struct
@@ -1213,6 +1230,8 @@ typedef struct
     PyObject *name;
 } PyDateTime_TimeZone;
 
+static PyDateTime_TimeZone * look_up_timezone(PyObject *offset, PyObject *name);
+
 /* Create new timezone instance checking offset range.  This
    function does not check the name argument.  Caller must assure
    that offset is a timedelta instance and name is either NULL
@@ -1221,12 +1240,19 @@ static PyObject *
 create_timezone(PyObject *offset, PyObject *name)
 {
     PyDateTime_TimeZone *self;
-    PyTypeObject *type = &PyDateTime_TimeZoneType;
+    datetime_state *st = get_datetime_state();
+    PyTypeObject *type = st->timezone_type;
 
     assert(offset != NULL);
     assert(PyDelta_Check(offset));
     assert(name == NULL || PyUnicode_Check(name));
 
+    self = look_up_timezone(offset, name);
+    if (self != NULL) {
+        return (PyObject *)self;
+    }
+    assert(!PyErr_Occurred());
+
     self = (PyDateTime_TimeZone *)(type->tp_alloc(type, 0));
     if (self == NULL) {
         return NULL;
@@ -1246,7 +1272,7 @@ new_timezone(PyObject *offset, PyObject *name)
     assert(name == NULL || PyUnicode_Check(name));
 
     if (name == NULL && delta_bool((PyDateTime_Delta *)offset) == 0) {
-        datetime_state *st = STATIC_STATE();
+        datetime_state *st = get_datetime_state();
         return Py_NewRef(st->utc);
     }
     if ((GET_TD_DAYS(offset) == -1 &&
@@ -1460,7 +1486,7 @@ tzinfo_from_isoformat_results(int rv, int tzoffset, int tz_useconds)
     if (rv == 1) {
         // Create a timezone from offset in seconds (0 returns UTC)
         if (tzoffset == 0) {
-            datetime_state *st = STATIC_STATE();
+            datetime_state *st = get_datetime_state();
             return Py_NewRef(st->utc);
         }
 
@@ -1893,7 +1919,7 @@ delta_to_microseconds(PyDateTime_Delta *self)
     x1 = PyLong_FromLong(GET_TD_DAYS(self));
     if (x1 == NULL)
         goto Done;
-    datetime_state *st = STATIC_STATE();
+    datetime_state *st = get_datetime_state();
     x2 = PyNumber_Multiply(x1, st->seconds_per_day);        /* days in seconds */
     if (x2 == NULL)
         goto Done;
@@ -1966,7 +1992,7 @@ microseconds_to_delta_ex(PyObject *pyus, PyTypeObject *type)
     PyObject *num = NULL;
     PyObject *result = NULL;
 
-    datetime_state *st = STATIC_STATE();
+    datetime_state *st = get_datetime_state();
     tuple = checked_divmod(pyus, st->us_per_second);
     if (tuple == NULL) {
         goto Done;
@@ -2019,7 +2045,7 @@ BadDivmod:
 }
 
 #define microseconds_to_delta(pymicros) \
-    microseconds_to_delta_ex(pymicros, &PyDateTime_DeltaType)
+    microseconds_to_delta_ex(pymicros, get_datetime_state()->delta_type)
 
 static PyObject *
 multiply_int_timedelta(PyObject *intobj, PyDateTime_Delta *delta)
@@ -2585,7 +2611,7 @@ delta_new(PyTypeObject *type, PyObject *args, PyObject *kw)
         y = accum("microseconds", x, us, _PyLong_GetOne(), &leftover_us);
         CLEANUP;
     }
-    datetime_state *st = STATIC_STATE();
+    datetime_state *st = get_datetime_state();
     if (ms) {
         y = accum("milliseconds", x, ms, st->us_per_ms, &leftover_us);
         CLEANUP;
@@ -2762,7 +2788,7 @@ delta_total_seconds(PyObject *self, PyObject *Py_UNUSED(ignored))
     if (total_microseconds == NULL)
         return NULL;
 
-    datetime_state *st = STATIC_STATE();
+    datetime_state *st = get_datetime_state();
     total_seconds = PyNumber_TrueDivide(total_microseconds, st->us_per_second);
 
     Py_DECREF(total_microseconds);
@@ -2885,6 +2911,25 @@ static PyTypeObject PyDateTime_DeltaType = {
     0,                                                  /* tp_free */
 };
 
+// XXX Can we make this const?
+static PyDateTime_Delta zero_delta = {
+    PyObject_HEAD_INIT(&PyDateTime_DeltaType)
+    /* Letting this be set lazily is a benign race. */
+    .hashcode = -1,
+};
+
+static PyDateTime_Delta *
+look_up_delta(int days, int seconds, int microseconds, PyTypeObject *type)
+{
+    if (days == 0 && seconds == 0 && microseconds == 0
+            && type == zero_delta.ob_base.ob_type)
+    {
+        return &zero_delta;
+    }
+    return NULL;
+}
+
+
 /*
  * PyDateTime_Date implementation.
  */
@@ -3475,8 +3520,9 @@ date_isocalendar(PyDateTime_Date *self, PyObject *Py_UNUSED(ignored))
         week = 0;
     }
 
-    PyObject* v = iso_calendar_date_new_impl(&PyDateTime_IsoCalendarDateType,
-                    year, week + 1, day + 1);
+    datetime_state *st = get_datetime_state();
+    PyObject *v = iso_calendar_date_new_impl(st->isocalendar_date_type,
+                                             year, week + 1, day + 1);
     if (v == NULL) {
         return NULL;
     }
@@ -3945,8 +3991,9 @@ timezone_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 {
     PyObject *offset;
     PyObject *name = NULL;
+    datetime_state *st = get_datetime_state();
     if (PyArg_ParseTupleAndKeywords(args, kw, "O!|U:timezone", timezone_kws,
-                                    &PyDateTime_DeltaType, &offset, &name))
+                                    st->delta_type, &offset, &name))
         return new_timezone(offset, name);
 
     return NULL;
@@ -3999,7 +4046,7 @@ timezone_repr(PyDateTime_TimeZone *self)
        to use Py_TYPE(self)->tp_name here. */
     const char *type_name = Py_TYPE(self)->tp_name;
 
-    datetime_state *st = STATIC_STATE();
+    datetime_state *st = get_datetime_state();
     if (((PyObject *)self) == st->utc) {
         return PyUnicode_FromFormat("%s.utc", type_name);
     }
@@ -4022,7 +4069,7 @@ timezone_str(PyDateTime_TimeZone *self)
     if (self->name != NULL) {
         return Py_NewRef(self->name);
     }
-    datetime_state *st = STATIC_STATE();
+    datetime_state *st = get_datetime_state();
     if ((PyObject *)self == st->utc ||
            (GET_TD_DAYS(self->offset) == 0 &&
             GET_TD_SECONDS(self->offset) == 0 &&
@@ -4175,6 +4222,23 @@ static PyTypeObject PyDateTime_TimeZoneType = {
     timezone_new,                     /* tp_new */
 };
 
+// XXX Can we make this const?
+static PyDateTime_TimeZone utc_timezone = {
+    PyObject_HEAD_INIT(&PyDateTime_TimeZoneType)
+    .offset = (PyObject *)&zero_delta,
+    .name = NULL,
+};
+
+static PyDateTime_TimeZone *
+look_up_timezone(PyObject *offset, PyObject *name)
+{
+    if (offset == utc_timezone.offset && name == NULL) {
+        return &utc_timezone;
+    }
+    return NULL;
+}
+
+
 /*
  * PyDateTime_Time implementation.
  */
@@ -4686,7 +4750,8 @@ time_fromisoformat(PyObject *cls, PyObject *tstr) {
     }
 
     PyObject *t;
-    if ( (PyTypeObject *)cls == &PyDateTime_TimeType ) {
+    datetime_state *st = get_datetime_state();
+    if ( (PyTypeObject *)cls == st->time_type) {
         t = new_time(hour, minute, second, microsecond, tzinfo, 0);
     } else {
         t = PyObject_CallFunction(cls, "iiiiO",
@@ -5284,9 +5349,10 @@ datetime_combine(PyObject *cls, PyObject *args, PyObject *kw)
     PyObject *tzinfo = NULL;
     PyObject *result = NULL;
 
+    datetime_state *st = get_datetime_state();
     if (PyArg_ParseTupleAndKeywords(args, kw, "O!O!|O:combine", keywords,
-                                    &PyDateTime_DateType, &date,
-                                    &PyDateTime_TimeType, &time, &tzinfo)) {
+                                    st->date_type, &date,
+                                    st->time_type, &time, &tzinfo)) {
         if (tzinfo == NULL) {
             if (HASTZINFO(time))
                 tzinfo = ((PyDateTime_Time *)time)->tzinfo;
@@ -6116,6 +6182,7 @@ local_timezone_from_timestamp(time_t timestamp)
     delta = new_delta(0, local_time_tm.tm_gmtoff, 0, 1);
 #else /* HAVE_STRUCT_TM_TM_ZONE */
     {
+        datetime_state *st = get_datetime_state();
         PyObject *local_time, *utc_time;
         struct tm utc_time_tm;
         char buf[100];
@@ -6170,10 +6237,11 @@ local_timezone(PyDateTime_DateTime *utc_time)
     PyObject *one_second;
     PyObject *seconds;
 
-    datetime_state *st = STATIC_STATE();
+    datetime_state *st = get_datetime_state();
     delta = datetime_subtract((PyObject *)utc_time, st->epoch);
     if (delta == NULL)
         return NULL;
+
     one_second = new_delta(0, 1, 0, 0);
     if (one_second == NULL) {
         Py_DECREF(delta);
@@ -6283,7 +6351,7 @@ datetime_astimezone(PyDateTime_DateTime *self, PyObject *args, PyObject *kw)
     if (result == NULL)
         return NULL;
 
-    datetime_state *st = STATIC_STATE();
+    datetime_state *st = get_datetime_state();
     /* Make sure result is aware and UTC. */
     if (!HASTZINFO(result)) {
         temp = (PyObject *)result;
@@ -6408,7 +6476,7 @@ datetime_timestamp(PyDateTime_DateTime *self, PyObject *Py_UNUSED(ignored))
     PyObject *result;
 
     if (HASTZINFO(self) && self->tzinfo != Py_None) {
-        datetime_state *st = STATIC_STATE();
+        datetime_state *st = get_datetime_state();
         PyObject *delta;
         delta = datetime_subtract((PyObject *)self, st->epoch);
         if (delta == NULL)
@@ -6706,50 +6774,48 @@ static PyMethodDef module_methods[] = {
     {NULL, NULL}
 };
 
+
+/* The C-API is process-global.  This violates interpreter isolation
+ * due to the objects stored here.  Thus each of those objects must
+ * be managed carefully. */
+// XXX Can we make this const?
+static PyDateTime_CAPI capi = {
+    /* The classes must be readied before used here.
+     * That will happen the first time the module is loaded.
+     * They aren't safe to be shared between interpreters,
+     * but that's okay as long as the module is single-phase init. */
+    .DateType = &PyDateTime_DateType,
+    .DateTimeType = &PyDateTime_DateTimeType,
+    .TimeType = &PyDateTime_TimeType,
+    .DeltaType = &PyDateTime_DeltaType,
+    .TZInfoType = &PyDateTime_TZInfoType,
+
+    .TimeZone_UTC = (PyObject *)&utc_timezone,
+
+    .Date_FromDate = new_date_ex,
+    .DateTime_FromDateAndTime = new_datetime_ex,
+    .Time_FromTime = new_time_ex,
+    .Delta_FromDelta = new_delta_ex,
+    .TimeZone_FromTimeZone = new_timezone,
+    .DateTime_FromTimestamp = datetime_fromtimestamp,
+    .Date_FromTimestamp = datetime_date_fromtimestamp_capi,
+    .DateTime_FromDateAndTimeAndFold = new_datetime_ex2,
+    .Time_FromTimeAndFold = new_time_ex2,
+};
+
 /* Get a new C API by calling this function.
  * Clients get at C API via PyDateTime_IMPORT, defined in datetime.h.
  */
 static inline PyDateTime_CAPI *
 get_datetime_capi(void)
 {
-    PyDateTime_CAPI *capi = PyMem_Malloc(sizeof(PyDateTime_CAPI));
-    if (capi == NULL) {
-        PyErr_NoMemory();
-        return NULL;
-    }
-    capi->DateType = &PyDateTime_DateType;
-    capi->DateTimeType = &PyDateTime_DateTimeType;
-    capi->TimeType = &PyDateTime_TimeType;
-    capi->DeltaType = &PyDateTime_DeltaType;
-    capi->TZInfoType = &PyDateTime_TZInfoType;
-    capi->Date_FromDate = new_date_ex;
-    capi->DateTime_FromDateAndTime = new_datetime_ex;
-    capi->Time_FromTime = new_time_ex;
-    capi->Delta_FromDelta = new_delta_ex;
-    capi->TimeZone_FromTimeZone = new_timezone;
-    capi->DateTime_FromTimestamp = datetime_fromtimestamp;
-    capi->Date_FromTimestamp = datetime_date_fromtimestamp_capi;
-    capi->DateTime_FromDateAndTimeAndFold = new_datetime_ex2;
-    capi->Time_FromTimeAndFold = new_time_ex2;
-    // Make sure this function is called after utc has
-    // been initialized.
-    datetime_state *st = STATIC_STATE();
-    assert(st->utc != NULL);
-    capi->TimeZone_UTC = st->utc; // borrowed ref
-    return capi;
-}
-
-static void
-datetime_destructor(PyObject *op)
-{
-    void *ptr = PyCapsule_GetPointer(op, PyDateTime_CAPSULE_NAME);
-    PyMem_Free(ptr);
+    return &capi;
 }
 
 static int
 datetime_clear(PyObject *module)
 {
-    datetime_state *st = STATIC_STATE();
+    datetime_state *st = get_datetime_state();
 
     Py_CLEAR(st->us_per_ms);
     Py_CLEAR(st->us_per_second);
@@ -6778,6 +6844,20 @@ create_timezone_from_delta(int days, int sec, int ms, int normalize)
 static int
 init_state(datetime_state *st)
 {
+    // While datetime uses global module "state", we unly initialize it once.
+    // The PyLong objects created here (once per process) are not decref'd.
+    if (st->initialized) {
+        return 0;
+    }
+
+    st->date_type = &PyDateTime_DateType;
+    st->datetime_type = &PyDateTime_DateTimeType;
+    st->delta_type = &PyDateTime_DeltaType;
+    st->isocalendar_date_type = &PyDateTime_IsoCalendarDateType;
+    st->time_type = &PyDateTime_TimeType;
+    st->tzinfo_type = &PyDateTime_TZInfoType;
+    st->timezone_type = &PyDateTime_TimeZoneType;
+
     st->us_per_ms = PyLong_FromLong(1000);
     if (st->us_per_ms == NULL) {
         return -1;
@@ -6822,6 +6902,9 @@ init_state(datetime_state *st)
     if (st->epoch == NULL) {
         return -1;
     }
+
+    st->initialized = 1;
+
     return 0;
 }
 
@@ -6854,6 +6937,11 @@ _datetime_exec(PyObject *module)
         goto error;
     }
 
+    datetime_state *st = get_datetime_state();
+    if (init_state(st) < 0) {
+        goto error;
+    }
+
 #define DATETIME_ADD_MACRO(dict, c, value_expr)         \
     do {                                                \
         PyObject *value = (value_expr);                 \
@@ -6868,39 +6956,34 @@ _datetime_exec(PyObject *module)
     } while(0)
 
     /* timedelta values */
-    PyObject *d = PyDateTime_DeltaType.tp_dict;
+    PyObject *d = st->delta_type->tp_dict;
     DATETIME_ADD_MACRO(d, "resolution", new_delta(0, 0, 1, 0));
     DATETIME_ADD_MACRO(d, "min", new_delta(-MAX_DELTA_DAYS, 0, 0, 0));
     DATETIME_ADD_MACRO(d, "max",
                        new_delta(MAX_DELTA_DAYS, 24*3600-1, 1000000-1, 0));
 
     /* date values */
-    d = PyDateTime_DateType.tp_dict;
+    d = st->date_type->tp_dict;
     DATETIME_ADD_MACRO(d, "min", new_date(1, 1, 1));
     DATETIME_ADD_MACRO(d, "max", new_date(MAXYEAR, 12, 31));
     DATETIME_ADD_MACRO(d, "resolution", new_delta(1, 0, 0, 0));
 
     /* time values */
-    d = PyDateTime_TimeType.tp_dict;
+    d = st->time_type->tp_dict;
     DATETIME_ADD_MACRO(d, "min", new_time(0, 0, 0, 0, Py_None, 0));
     DATETIME_ADD_MACRO(d, "max", new_time(23, 59, 59, 999999, Py_None, 0));
     DATETIME_ADD_MACRO(d, "resolution", new_delta(0, 0, 1, 0));
 
     /* datetime values */
-    d = PyDateTime_DateTimeType.tp_dict;
+    d = st->datetime_type->tp_dict;
     DATETIME_ADD_MACRO(d, "min",
                        new_datetime(1, 1, 1, 0, 0, 0, 0, Py_None, 0));
     DATETIME_ADD_MACRO(d, "max", new_datetime(MAXYEAR, 12, 31, 23, 59, 59,
                                               999999, Py_None, 0));
     DATETIME_ADD_MACRO(d, "resolution", new_delta(0, 0, 1, 0));
 
-    datetime_state *st = STATIC_STATE();
-    if (init_state(st) < 0) {
-        goto error;
-    }
-
     /* timezone values */
-    d = PyDateTime_TimeZoneType.tp_dict;
+    d = st->timezone_type->tp_dict;
     if (PyDict_SetItemString(d, "utc", st->utc) < 0) {
         goto error;
     }
@@ -6933,14 +7016,9 @@ _datetime_exec(PyObject *module)
     if (capi == NULL) {
         goto error;
     }
-    PyObject *capsule = PyCapsule_New(capi, PyDateTime_CAPSULE_NAME,
-                                      datetime_destructor);
-    if (capsule == NULL) {
-        PyMem_Free(capi);
-        goto error;
-    }
+    PyObject *capsule = PyCapsule_New(capi, PyDateTime_CAPSULE_NAME, NULL);
+    // (capsule == NULL) is handled by PyModule_Add
     if (PyModule_Add(module, "datetime_CAPI", capsule) < 0) {
-        PyMem_Free(capi);
         goto error;
     }