From 4c1325e3b4afc348f08bc69cae3b0339118c5e8e Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Sun, 28 Apr 2024 07:06:35 +0900
Subject: [PATCH 01/18] set capi-struct pointer to interp state

---
 Include/datetime.h               | 25 +++++++++++++++++------
 Include/internal/pycore_interp.h |  1 +
 Lib/test/test_capi/test_misc.py  | 16 +++++++++++++++
 Modules/_datetimemodule.c        | 15 ++++++++++++++
 Modules/_testmultiphase.c        | 35 ++++++++++++++++++++++++++++++++
 5 files changed, 86 insertions(+), 6 deletions(-)

diff --git a/Include/datetime.h b/Include/datetime.h
index b78cc0e8e2e5ac..abb2295b17099c 100644
--- a/Include/datetime.h
+++ b/Include/datetime.h
@@ -155,7 +155,7 @@ typedef struct
 
 
 /* Define structure for C API. */
-typedef struct {
+typedef struct _pydatetime_capi {
     /* type objects */
     PyTypeObject *DateType;
     PyTypeObject *DateTimeType;
@@ -182,7 +182,8 @@ typedef struct {
     PyObject *(*DateTime_FromDateAndTimeAndFold)(int, int, int, int, int, int, int,
         PyObject*, int, PyTypeObject*);
     PyObject *(*Time_FromTimeAndFold)(int, int, int, int, PyObject*, int, PyTypeObject*);
-
+    struct _pydatetime_capi *(*_get_capi_by_interp)(void);
+    void (*_set_capi_by_interp)(struct _pydatetime_capi *);
 } PyDateTime_CAPI;
 
 #define PyDateTime_CAPSULE_NAME "datetime.datetime_CAPI"
@@ -194,10 +195,22 @@ typedef struct {
  * */
 #ifndef _PY_DATETIME_IMPL
 /* Define global variable for the C API and a macro for setting it. */
-static PyDateTime_CAPI *PyDateTimeAPI = NULL;
-
-#define PyDateTime_IMPORT \
-    PyDateTimeAPI = (PyDateTime_CAPI *)PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0)
+static PyDateTime_CAPI *
+_get_pydatetime_capi_dummy(void)
+{
+    return NULL;
+}
+static PyDateTime_CAPI *(*_get_pydatetime_capi)(void) = _get_pydatetime_capi_dummy;
+#define PyDateTimeAPI _get_pydatetime_capi()
+
+static inline void pydatetime_import(void) {
+    PyDateTime_CAPI *capi = PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0);
+    if (capi) {
+        capi->_set_capi_by_interp(capi);
+        _get_pydatetime_capi = capi->_get_capi_by_interp;
+    }
+}
+#define PyDateTime_IMPORT pydatetime_import()
 
 /* Macro for access to the UTC singleton */
 #define PyDateTime_TimeZone_UTC PyDateTimeAPI->TimeZone_UTC
diff --git a/Include/internal/pycore_interp.h b/Include/internal/pycore_interp.h
index d38959e3ce4ec5..eb21e10fb224ee 100644
--- a/Include/internal/pycore_interp.h
+++ b/Include/internal/pycore_interp.h
@@ -236,6 +236,7 @@ struct _is {
     // more comments.
     struct _obmalloc_state *obmalloc;
 
+    void *datetime_capi;
     PyObject *audit_hooks;
     PyType_WatchCallback type_watchers[TYPE_MAX_WATCHERS];
     PyCode_WatchCallback code_watchers[CODE_MAX_WATCHERS];
diff --git a/Lib/test/test_capi/test_misc.py b/Lib/test/test_capi/test_misc.py
index 020e8493e57c0c..98849b8d179b83 100644
--- a/Lib/test/test_capi/test_misc.py
+++ b/Lib/test/test_capi/test_misc.py
@@ -2282,6 +2282,22 @@ def test_module_state_shared_in_global(self):
         subinterp_attr_id = os.read(r, 100)
         self.assertEqual(main_attr_id, subinterp_attr_id)
 
+    @unittest.skipIf(_testmultiphase is None, "test requires _testmultiphase module")
+    def test_datetime_capi_client(self):
+        script = textwrap.dedent("""
+            import importlib.machinery
+            import importlib.util
+            fullname = '_test_datetime_capi_client'
+            origin = importlib.util.find_spec('_testmultiphase').origin
+            loader = importlib.machinery.ExtensionFileLoader(fullname, origin)
+            spec = importlib.util.spec_from_loader(fullname, loader)
+            module = importlib.util.module_from_spec(spec)
+            spec.loader.exec_module(module)
+        """)
+        exec(script)
+        ret = support.run_in_subinterp(script)
+        self.assertEqual(ret, 0)
+
 
 @requires_subinterpreters
 class InterpreterConfigTests(unittest.TestCase):
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index 06004e258b2eff..a94924e30db187 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -63,6 +63,18 @@ static datetime_state _datetime_global_state;
 
 #define STATIC_STATE() (&_datetime_global_state)
 
+void
+set_datetime_capi_by_interp(PyDateTime_CAPI *capi)
+{
+    _PyInterpreterState_GET()->datetime_capi = capi;
+}
+
+PyDateTime_CAPI *
+get_datetime_capi_by_interp(void)
+{
+    return (PyDateTime_CAPI *)_PyInterpreterState_GET()->datetime_capi;
+}
+
 /* 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
  * API returns a C long.  In such cases, we have to ensure that the
@@ -6736,12 +6748,15 @@ get_datetime_capi(void)
     datetime_state *st = STATIC_STATE();
     assert(st->utc != NULL);
     capi->TimeZone_UTC = st->utc; // borrowed ref
+    capi->_set_capi_by_interp = set_datetime_capi_by_interp;
+    capi->_get_capi_by_interp = get_datetime_capi_by_interp;
     return capi;
 }
 
 static void
 datetime_destructor(PyObject *op)
 {
+    set_datetime_capi_by_interp(NULL);
     void *ptr = PyCapsule_GetPointer(op, PyDateTime_CAPSULE_NAME);
     PyMem_Free(ptr);
 }
diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index 21c5f696a4f2ec..1d25919ff3b511 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -952,3 +952,38 @@ PyInit__test_shared_gil_only(void)
 {
     return PyModuleDef_Init(&shared_gil_only_def);
 }
+
+
+#include "datetime.h"
+
+static int
+datetime_capi_client_exec(PyObject *m)
+{
+    _get_pydatetime_capi = _get_pydatetime_capi_dummy;
+    if (PyDateTimeAPI != NULL) {
+        return -1;
+    }
+    PyDateTime_IMPORT;
+    if (PyDateTimeAPI == NULL) {
+        return -1;
+    }
+    if (PyDateTimeAPI != PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0)) {
+        return -1;
+    }
+    return 0;
+}
+
+static PyModuleDef_Slot datetime_capi_client_slots[] = {
+    {Py_mod_exec, datetime_capi_client_exec},
+    {Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
+    {0, NULL},
+};
+
+static PyModuleDef datetime_capi_client_def = TEST_MODULE_DEF(
+    "_testmultiphase_datetime_capi_client", datetime_capi_client_slots, NULL);
+
+PyMODINIT_FUNC
+PyInit__test_datetime_capi_client(void)
+{
+    return PyModuleDef_Init(&datetime_capi_client_def);
+}

From fecd19228ac43eb7a076cb5a04cbaed92a336fa4 Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Sun, 28 Apr 2024 08:34:22 +0900
Subject: [PATCH 02/18] globals-to-fix.tsv

---
 Include/datetime.h                          | 1 +
 Tools/c-analyzer/cpython/globals-to-fix.tsv | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/Include/datetime.h b/Include/datetime.h
index abb2295b17099c..b6b96ca433eafc 100644
--- a/Include/datetime.h
+++ b/Include/datetime.h
@@ -182,6 +182,7 @@ typedef struct _pydatetime_capi {
     PyObject *(*DateTime_FromDateAndTimeAndFold)(int, int, int, int, int, int, int,
         PyObject*, int, PyTypeObject*);
     PyObject *(*Time_FromTimeAndFold)(int, int, int, int, PyObject*, int, PyTypeObject*);
+
     struct _pydatetime_capi *(*_get_capi_by_interp)(void);
     void (*_set_capi_by_interp)(struct _pydatetime_capi *);
 } PyDateTime_CAPI;
diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index 79a8f850ec1451..604b05d40e0436 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -446,7 +446,7 @@ Modules/_tkinter.c	-	trbInCmd	-
 ## initialized once
 
 ## other
-Include/datetime.h	-	PyDateTimeAPI	-
+Include/datetime.h	-	_get_pydatetime_capi	-
 Modules/_ctypes/cfield.c	_ctypes_get_fielddesc	initialized	-
 Modules/_ctypes/malloc_closure.c	-	_pagesize	-
 Modules/_cursesmodule.c	-	initialised	-

From 2bdf01cc3f54de901823eea8b0be79a48edaf309 Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Sun, 28 Apr 2024 09:08:14 +0900
Subject: [PATCH 03/18] make exit code individual

---
 Modules/_testmultiphase.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index 1d25919ff3b511..fa0caa30f7770e 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -965,10 +965,10 @@ datetime_capi_client_exec(PyObject *m)
     }
     PyDateTime_IMPORT;
     if (PyDateTimeAPI == NULL) {
-        return -1;
+        return -2;
     }
     if (PyDateTimeAPI != PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0)) {
-        return -1;
+        return -3;
     }
     return 0;
 }

From bead43116ed999766545a5a7f09394e18c1d8926 Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Sun, 28 Apr 2024 10:57:09 +0900
Subject: [PATCH 04/18] fix gil-disabled test

---
 Modules/_testmultiphase.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index fa0caa30f7770e..9e16b7f039b838 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -964,12 +964,11 @@ datetime_capi_client_exec(PyObject *m)
         return -1;
     }
     PyDateTime_IMPORT;
-    if (PyDateTimeAPI == NULL) {
-        return -2;
-    }
+    PyErr_Clear();
     if (PyDateTimeAPI != PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0)) {
-        return -3;
+        return -1;
     }
+    PyErr_Clear();
     return 0;
 }
 

From d361ee48db5309e61e883226ef19b9ef412cb2be Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Mon, 29 Apr 2024 23:14:25 +0900
Subject: [PATCH 05/18] add an assertion in datetime_destructor()

---
 Modules/_datetimemodule.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index a94924e30db187..3b08f147ad6606 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -6756,9 +6756,10 @@ get_datetime_capi(void)
 static void
 datetime_destructor(PyObject *op)
 {
-    set_datetime_capi_by_interp(NULL);
     void *ptr = PyCapsule_GetPointer(op, PyDateTime_CAPSULE_NAME);
+    assert(ptr == get_datetime_capi_by_interp());
     PyMem_Free(ptr);
+    set_datetime_capi_by_interp(NULL);
 }
 
 static int

From 3b721bc0331110e66ae65dda49afc44b92ac280e Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Mon, 29 Apr 2024 23:35:11 +0900
Subject: [PATCH 06/18] fix assert()

---
 Modules/_datetimemodule.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index 3b08f147ad6606..a60c62e339f248 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -6757,7 +6757,7 @@ static void
 datetime_destructor(PyObject *op)
 {
     void *ptr = PyCapsule_GetPointer(op, PyDateTime_CAPSULE_NAME);
-    assert(ptr == get_datetime_capi_by_interp());
+    assert(!get_datetime_capi_by_interp() || ptr == get_datetime_capi_by_interp());
     PyMem_Free(ptr);
     set_datetime_capi_by_interp(NULL);
 }

From 53b0219e2e7b60ac87156ed7c680fa582c34c477 Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Tue, 30 Apr 2024 02:59:10 +0900
Subject: [PATCH 07/18] add a struct for internal use

---
 Include/datetime.h        | 14 +++++++++-----
 Modules/_datetimemodule.c |  6 +++---
 2 files changed, 12 insertions(+), 8 deletions(-)

diff --git a/Include/datetime.h b/Include/datetime.h
index b6b96ca433eafc..40211c26ecaec2 100644
--- a/Include/datetime.h
+++ b/Include/datetime.h
@@ -155,7 +155,7 @@ typedef struct
 
 
 /* Define structure for C API. */
-typedef struct _pydatetime_capi {
+typedef struct {
     /* type objects */
     PyTypeObject *DateType;
     PyTypeObject *DateTimeType;
@@ -183,12 +183,16 @@ typedef struct _pydatetime_capi {
         PyObject*, int, PyTypeObject*);
     PyObject *(*Time_FromTimeAndFold)(int, int, int, int, PyObject*, int, PyTypeObject*);
 
-    struct _pydatetime_capi *(*_get_capi_by_interp)(void);
-    void (*_set_capi_by_interp)(struct _pydatetime_capi *);
 } PyDateTime_CAPI;
 
 #define PyDateTime_CAPSULE_NAME "datetime.datetime_CAPI"
 
+/* Internal use */
+typedef struct {
+    PyDateTime_CAPI api;
+    PyDateTime_CAPI *(*_get_capi_by_interp)(void);
+    void (*_set_capi_by_interp)(PyDateTime_CAPI *);
+} _pydatetime_capi;
 
 /* This block is only used as part of the public API and should not be
  * included in _datetimemodule.c, which does not use the C API capsule.
@@ -205,9 +209,9 @@ static PyDateTime_CAPI *(*_get_pydatetime_capi)(void) = _get_pydatetime_capi_dum
 #define PyDateTimeAPI _get_pydatetime_capi()
 
 static inline void pydatetime_import(void) {
-    PyDateTime_CAPI *capi = PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0);
+    _pydatetime_capi *capi = PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0);
     if (capi) {
-        capi->_set_capi_by_interp(capi);
+        capi->_set_capi_by_interp((PyDateTime_CAPI *)capi);
         _get_pydatetime_capi = capi->_get_capi_by_interp;
     }
 }
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index a60c62e339f248..a3ba202b4539d7 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -6724,7 +6724,7 @@ static PyMethodDef module_methods[] = {
 static inline PyDateTime_CAPI *
 get_datetime_capi(void)
 {
-    PyDateTime_CAPI *capi = PyMem_Malloc(sizeof(PyDateTime_CAPI));
+    PyDateTime_CAPI *capi = PyMem_Malloc(sizeof(_pydatetime_capi));
     if (capi == NULL) {
         PyErr_NoMemory();
         return NULL;
@@ -6748,8 +6748,8 @@ get_datetime_capi(void)
     datetime_state *st = STATIC_STATE();
     assert(st->utc != NULL);
     capi->TimeZone_UTC = st->utc; // borrowed ref
-    capi->_set_capi_by_interp = set_datetime_capi_by_interp;
-    capi->_get_capi_by_interp = get_datetime_capi_by_interp;
+    ((_pydatetime_capi *)capi)->_set_capi_by_interp = set_datetime_capi_by_interp;
+    ((_pydatetime_capi *)capi)->_get_capi_by_interp = get_datetime_capi_by_interp;
     return capi;
 }
 

From 8b10d7002762b8bac01aa63f2b9a559b62bf40b9 Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Tue, 30 Apr 2024 21:24:02 +0900
Subject: [PATCH 08/18] try hiding internal info

---
 Include/datetime.h                          | 29 +++++----------------
 Modules/_datetimemodule.c                   | 29 ++++++++++++++++-----
 Modules/_testcapi/datetime.c                |  3 +++
 Modules/_testmultiphase.c                   |  2 +-
 Tools/c-analyzer/cpython/globals-to-fix.tsv |  1 -
 5 files changed, 32 insertions(+), 32 deletions(-)

diff --git a/Include/datetime.h b/Include/datetime.h
index 40211c26ecaec2..b023da24be35f6 100644
--- a/Include/datetime.h
+++ b/Include/datetime.h
@@ -187,35 +187,18 @@ typedef struct {
 
 #define PyDateTime_CAPSULE_NAME "datetime.datetime_CAPI"
 
-/* Internal use */
-typedef struct {
-    PyDateTime_CAPI api;
-    PyDateTime_CAPI *(*_get_capi_by_interp)(void);
-    void (*_set_capi_by_interp)(PyDateTime_CAPI *);
-} _pydatetime_capi;
+PyAPI_FUNC(void) _PyDateTimeAPI_Import(void);
+PyAPI_FUNC(void) _PyDateTimeAPI_Clear(void);
+PyAPI_FUNC(PyDateTime_CAPI *) _PyDateTimeAPI_Get(void);
 
 /* This block is only used as part of the public API and should not be
  * included in _datetimemodule.c, which does not use the C API capsule.
  * See bpo-35081 for more details.
  * */
 #ifndef _PY_DATETIME_IMPL
-/* Define global variable for the C API and a macro for setting it. */
-static PyDateTime_CAPI *
-_get_pydatetime_capi_dummy(void)
-{
-    return NULL;
-}
-static PyDateTime_CAPI *(*_get_pydatetime_capi)(void) = _get_pydatetime_capi_dummy;
-#define PyDateTimeAPI _get_pydatetime_capi()
-
-static inline void pydatetime_import(void) {
-    _pydatetime_capi *capi = PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0);
-    if (capi) {
-        capi->_set_capi_by_interp((PyDateTime_CAPI *)capi);
-        _get_pydatetime_capi = capi->_get_capi_by_interp;
-    }
-}
-#define PyDateTime_IMPORT pydatetime_import()
+
+#define PyDateTimeAPI _PyDateTimeAPI_Get()
+#define PyDateTime_IMPORT _PyDateTimeAPI_Import()
 
 /* Macro for access to the UTC singleton */
 #define PyDateTime_TimeZone_UTC PyDateTimeAPI->TimeZone_UTC
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index a3ba202b4539d7..ecccf93e32ab00 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -63,18 +63,35 @@ static datetime_state _datetime_global_state;
 
 #define STATIC_STATE() (&_datetime_global_state)
 
-void
+static inline void
 set_datetime_capi_by_interp(PyDateTime_CAPI *capi)
 {
     _PyInterpreterState_GET()->datetime_capi = capi;
 }
 
+void
+_PyDateTimeAPI_Import(void)
+{
+    PyDateTime_CAPI *capi = PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0);
+    if (capi) {
+        // PyInit__datetime() is not called when the module is already loaded
+        // with single-phase init.
+        set_datetime_capi_by_interp((PyDateTime_CAPI *)capi);
+    }
+}
+
 PyDateTime_CAPI *
-get_datetime_capi_by_interp(void)
+_PyDateTimeAPI_Get(void)
 {
     return (PyDateTime_CAPI *)_PyInterpreterState_GET()->datetime_capi;
 }
 
+void
+_PyDateTimeAPI_Clear(void)
+{
+    set_datetime_capi_by_interp(NULL);
+}
+
 /* 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
  * API returns a C long.  In such cases, we have to ensure that the
@@ -6724,7 +6741,7 @@ static PyMethodDef module_methods[] = {
 static inline PyDateTime_CAPI *
 get_datetime_capi(void)
 {
-    PyDateTime_CAPI *capi = PyMem_Malloc(sizeof(_pydatetime_capi));
+    PyDateTime_CAPI *capi = PyMem_Malloc(sizeof(PyDateTime_CAPI));
     if (capi == NULL) {
         PyErr_NoMemory();
         return NULL;
@@ -6748,8 +6765,6 @@ get_datetime_capi(void)
     datetime_state *st = STATIC_STATE();
     assert(st->utc != NULL);
     capi->TimeZone_UTC = st->utc; // borrowed ref
-    ((_pydatetime_capi *)capi)->_set_capi_by_interp = set_datetime_capi_by_interp;
-    ((_pydatetime_capi *)capi)->_get_capi_by_interp = get_datetime_capi_by_interp;
     return capi;
 }
 
@@ -6757,9 +6772,7 @@ static void
 datetime_destructor(PyObject *op)
 {
     void *ptr = PyCapsule_GetPointer(op, PyDateTime_CAPSULE_NAME);
-    assert(!get_datetime_capi_by_interp() || ptr == get_datetime_capi_by_interp());
     PyMem_Free(ptr);
-    set_datetime_capi_by_interp(NULL);
 }
 
 static int
@@ -6959,6 +6972,8 @@ _datetime_exec(PyObject *module)
         PyMem_Free(capi);
         goto error;
     }
+    /* Ensure that the newest capi is used on multi-phase init */
+    set_datetime_capi_by_interp(capi);
 
     /* A 4-year cycle has an extra leap day over what we'd get from
      * pasting together 4 single years.
diff --git a/Modules/_testcapi/datetime.c b/Modules/_testcapi/datetime.c
index b1796039f0d83a..7050f492bfa745 100644
--- a/Modules/_testcapi/datetime.c
+++ b/Modules/_testcapi/datetime.c
@@ -8,6 +8,9 @@ static int test_run_counter = 0;
 static PyObject *
 test_datetime_capi(PyObject *self, PyObject *args)
 {
+    if (!test_run_counter) {
+        _PyDateTimeAPI_Clear();
+    }
     if (PyDateTimeAPI) {
         if (test_run_counter) {
             /* Probably regrtest.py -R */
diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index 9e16b7f039b838..29114b75d99385 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -959,7 +959,7 @@ PyInit__test_shared_gil_only(void)
 static int
 datetime_capi_client_exec(PyObject *m)
 {
-    _get_pydatetime_capi = _get_pydatetime_capi_dummy;
+    _PyDateTimeAPI_Clear();
     if (PyDateTimeAPI != NULL) {
         return -1;
     }
diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index 604b05d40e0436..ae6a579dae1b23 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -446,7 +446,6 @@ Modules/_tkinter.c	-	trbInCmd	-
 ## initialized once
 
 ## other
-Include/datetime.h	-	_get_pydatetime_capi	-
 Modules/_ctypes/cfield.c	_ctypes_get_fielddesc	initialized	-
 Modules/_ctypes/malloc_closure.c	-	_pagesize	-
 Modules/_cursesmodule.c	-	initialised	-

From fb0f5efdf95cf56b288ce70bfddac18addf22fda Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Wed, 1 May 2024 04:40:27 +0900
Subject: [PATCH 09/18] apply suggested changes

---
 Lib/test/test_capi/test_misc.py |  2 +-
 Modules/_datetimemodule.c       |  2 +-
 Modules/_testmultiphase.c       | 49 +++++++++++++++++++++++++++++++--
 3 files changed, 48 insertions(+), 5 deletions(-)

diff --git a/Lib/test/test_capi/test_misc.py b/Lib/test/test_capi/test_misc.py
index 98849b8d179b83..9786e0d88cbf66 100644
--- a/Lib/test/test_capi/test_misc.py
+++ b/Lib/test/test_capi/test_misc.py
@@ -2294,7 +2294,7 @@ def test_datetime_capi_client(self):
             module = importlib.util.module_from_spec(spec)
             spec.loader.exec_module(module)
         """)
-        exec(script)
+        exec(script)  # run main interp first
         ret = support.run_in_subinterp(script)
         self.assertEqual(ret, 0)
 
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index ecccf93e32ab00..356956144d9865 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -76,7 +76,7 @@ _PyDateTimeAPI_Import(void)
     if (capi) {
         // PyInit__datetime() is not called when the module is already loaded
         // with single-phase init.
-        set_datetime_capi_by_interp((PyDateTime_CAPI *)capi);
+        set_datetime_capi_by_interp(capi);
     }
 }
 
diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index 29114b75d99385..2a7a79c15170b7 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -956,16 +956,59 @@ PyInit__test_shared_gil_only(void)
 
 #include "datetime.h"
 
+static int
+datetime_capi_import_with_error(void)
+{
+    static int multiphase = -1;
+    int ismain = PyInterpreterState_Get() == PyInterpreterState_Main();
+    if (ismain) {
+        PyObject *module = PyImport_ImportModule("_datetime");
+        if (module == NULL) {
+            return -1;
+        }
+        PyModuleDef *def = PyModule_GetDef(module);
+        Py_DECREF(module);
+        if (def && def->m_size >= 0) {
+            multiphase = 1;
+        }
+        else {
+            multiphase = 0;
+        }
+    }
+    if (multiphase < 0) {
+        PyErr_SetString(PyExc_AssertionError,
+                        "Main interpreter must be loaded first.");
+        return -1;
+    }
+
+    _PyDateTimeAPI_Import();
+    if (!PyErr_Occurred()) {
+        return 0;
+    }
+#ifdef Py_GIL_DISABLED
+    if (!ismain && !multiphase) {
+        PyErr_WriteUnraisable(NULL);
+        return 0;
+    }
+#endif
+    return -1;
+}
+
 static int
 datetime_capi_client_exec(PyObject *m)
 {
     _PyDateTimeAPI_Clear();
-    if (PyDateTimeAPI != NULL) {
+    if (_PyDateTimeAPI_Get() != NULL) {
+        PyErr_SetString(PyExc_AssertionError,
+                        "DateTime API is expected to remain NULL.");
+        return -1;
+    }
+    if (datetime_capi_import_with_error() < 0) {
         return -1;
     }
-    PyDateTime_IMPORT;
-    PyErr_Clear();
     if (PyDateTimeAPI != PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0)) {
+        PyErr_SetString(PyExc_AssertionError,
+                        "DateTime API does not match Capsule CAPI.");
         return -1;
     }
     PyErr_Clear();

From 7de45acc8b3211a406e88acbb06a0a5d6774a908 Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Wed, 1 May 2024 05:34:47 +0900
Subject: [PATCH 10/18] ignored.tsv

---
 Modules/_testmultiphase.c            | 10 +++++-----
 Tools/c-analyzer/cpython/ignored.tsv |  1 +
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index 2a7a79c15170b7..b8f289d5150552 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -959,7 +959,7 @@ PyInit__test_shared_gil_only(void)
 static int
 datetime_capi_import_with_error(void)
 {
-    static int multiphase = -1;
+    static int is_datetime_multiphase = -1;
     int ismain = PyInterpreterState_Get() == PyInterpreterState_Main();
     if (ismain) {
         PyObject *module = PyImport_ImportModule("_datetime");
@@ -969,13 +969,13 @@ datetime_capi_import_with_error(void)
         PyModuleDef *def = PyModule_GetDef(module);
         Py_DECREF(module);
         if (def && def->m_size >= 0) {
-            multiphase = 1;
+            is_datetime_multiphase = 1;
         }
         else {
-            multiphase = 0;
+            is_datetime_multiphase = 0;
         }
     }
-    if (multiphase < 0) {
+    if (is_datetime_multiphase < 0) {
         PyErr_SetString(PyExc_AssertionError,
                         "Main interpreter must be loaded first.");
         return -1;
@@ -986,7 +986,7 @@ datetime_capi_import_with_error(void)
         return 0;
     }
 #ifdef Py_GIL_DISABLED
-    if (!ismain && !multiphase) {
+    if (!ismain && !is_datetime_multiphase) {
         PyErr_WriteUnraisable(NULL);
         return 0;
     }
diff --git a/Tools/c-analyzer/cpython/ignored.tsv b/Tools/c-analyzer/cpython/ignored.tsv
index 87b695de23e25e..e87f91a45272dd 100644
--- a/Tools/c-analyzer/cpython/ignored.tsv
+++ b/Tools/c-analyzer/cpython/ignored.tsv
@@ -576,6 +576,7 @@ Modules/_testmultiphase.c	-	def_nonmodule_with_methods	-
 Modules/_testmultiphase.c	-	main_def	-
 Modules/_testmultiphase.c	-	main_slots	-
 Modules/_testmultiphase.c	-	meth_state_access_slots	-
+Modules/_testmultiphase.c	-	is_datetime_multiphase	-
 Modules/_testmultiphase.c	-	nonmodule_methods	-
 Modules/_testmultiphase.c	-	null_slots_def	-
 Modules/_testmultiphase.c	-	slots_bad_large	-

From f412c55577e3aab0a030f51e21439179f1275c32 Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Wed, 1 May 2024 05:56:12 +0900
Subject: [PATCH 11/18] globals-to-fix.tsv

---
 Tools/c-analyzer/cpython/globals-to-fix.tsv | 1 +
 Tools/c-analyzer/cpython/ignored.tsv        | 1 -
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index ae6a579dae1b23..9f6cf520af261a 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -456,6 +456,7 @@ Modules/_elementtree.c	-	expat_capi	-
 Modules/readline.c	-	libedit_append_replace_history_offset	-
 Modules/readline.c	-	using_libedit_emulation	-
 Modules/readline.c	-	libedit_history_start	-
+Modules/_testmultiphase.c	-	is_datetime_multiphase	-
 
 ##-----------------------
 ## state
diff --git a/Tools/c-analyzer/cpython/ignored.tsv b/Tools/c-analyzer/cpython/ignored.tsv
index e87f91a45272dd..87b695de23e25e 100644
--- a/Tools/c-analyzer/cpython/ignored.tsv
+++ b/Tools/c-analyzer/cpython/ignored.tsv
@@ -576,7 +576,6 @@ Modules/_testmultiphase.c	-	def_nonmodule_with_methods	-
 Modules/_testmultiphase.c	-	main_def	-
 Modules/_testmultiphase.c	-	main_slots	-
 Modules/_testmultiphase.c	-	meth_state_access_slots	-
-Modules/_testmultiphase.c	-	is_datetime_multiphase	-
 Modules/_testmultiphase.c	-	nonmodule_methods	-
 Modules/_testmultiphase.c	-	null_slots_def	-
 Modules/_testmultiphase.c	-	slots_bad_large	-

From c00ed1f71d261138f2d02aaf401a86976a44669a Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Wed, 1 May 2024 06:26:18 +0900
Subject: [PATCH 12/18] globals-to-fix.tsv

---
 Tools/c-analyzer/cpython/globals-to-fix.tsv | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index 9f6cf520af261a..bf950f95072751 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -456,7 +456,7 @@ Modules/_elementtree.c	-	expat_capi	-
 Modules/readline.c	-	libedit_append_replace_history_offset	-
 Modules/readline.c	-	using_libedit_emulation	-
 Modules/readline.c	-	libedit_history_start	-
-Modules/_testmultiphase.c	-	is_datetime_multiphase	-
+Modules/_testmultiphase.c	datetime_capi_import_with_error	is_datetime_multiphase	-
 
 ##-----------------------
 ## state

From e4986f5a13907d3b892e4be5384baa2ed5ee92de Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Wed, 1 May 2024 06:35:12 +0900
Subject: [PATCH 13/18] ignored.tsv again

---
 Tools/c-analyzer/cpython/globals-to-fix.tsv | 1 -
 Tools/c-analyzer/cpython/ignored.tsv        | 1 +
 2 files changed, 1 insertion(+), 1 deletion(-)

diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index bf950f95072751..ae6a579dae1b23 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -456,7 +456,6 @@ Modules/_elementtree.c	-	expat_capi	-
 Modules/readline.c	-	libedit_append_replace_history_offset	-
 Modules/readline.c	-	using_libedit_emulation	-
 Modules/readline.c	-	libedit_history_start	-
-Modules/_testmultiphase.c	datetime_capi_import_with_error	is_datetime_multiphase	-
 
 ##-----------------------
 ## state
diff --git a/Tools/c-analyzer/cpython/ignored.tsv b/Tools/c-analyzer/cpython/ignored.tsv
index 87b695de23e25e..11e56658951af8 100644
--- a/Tools/c-analyzer/cpython/ignored.tsv
+++ b/Tools/c-analyzer/cpython/ignored.tsv
@@ -591,6 +591,7 @@ Modules/_testmultiphase.c	-	slots_exec_unreported_exception	-
 Modules/_testmultiphase.c	-	slots_nonmodule_with_exec_slots	-
 Modules/_testmultiphase.c	-	testexport_methods	-
 Modules/_testmultiphase.c	-	uninitialized_def	-
+Modules/_testmultiphase.c	datetime_capi_import_with_error	is_datetime_multiphase	-
 Modules/_testsinglephase.c	-	global_state	-
 Modules/_xxtestfuzz/_xxtestfuzz.c	-	_fuzzmodule	-
 Modules/_xxtestfuzz/_xxtestfuzz.c	-	module_methods	-

From 39e17c72359fb53cbdf17e7188480a37ce6fecb8 Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Wed, 1 May 2024 06:53:25 +0900
Subject: [PATCH 14/18] run main interp twice in test

---
 Lib/test/test_capi/test_misc.py | 1 +
 Modules/_testmultiphase.c       | 2 +-
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/Lib/test/test_capi/test_misc.py b/Lib/test/test_capi/test_misc.py
index 9786e0d88cbf66..2cbaac346e915c 100644
--- a/Lib/test/test_capi/test_misc.py
+++ b/Lib/test/test_capi/test_misc.py
@@ -2295,6 +2295,7 @@ def test_datetime_capi_client(self):
             spec.loader.exec_module(module)
         """)
         exec(script)  # run main interp first
+        exec(script)  # run main interp twice
         ret = support.run_in_subinterp(script)
         self.assertEqual(ret, 0)
 
diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index b8f289d5150552..ba19b8b14f73af 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -961,7 +961,7 @@ datetime_capi_import_with_error(void)
 {
     static int is_datetime_multiphase = -1;
     int ismain = PyInterpreterState_Get() == PyInterpreterState_Main();
-    if (ismain) {
+    if (ismain && is_datetime_multiphase < 0) {
         PyObject *module = PyImport_ImportModule("_datetime");
         if (module == NULL) {
             return -1;

From 7aa369eccc5ef475ba5b73b8ecbb4a6ee9ba9c79 Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Wed, 1 May 2024 07:08:37 +0900
Subject: [PATCH 15/18] add a comment to a test

---
 Modules/_testmultiphase.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index ba19b8b14f73af..6860fbddb59df4 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -987,6 +987,7 @@ datetime_capi_import_with_error(void)
     }
 #ifdef Py_GIL_DISABLED
     if (!ismain && !is_datetime_multiphase) {
+        // _datetime module and Capsule are not imported
         PyErr_WriteUnraisable(NULL);
         return 0;
     }

From 0769c965cf6de74e1f947ffcda2533fb6b408aee Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Wed, 1 May 2024 18:41:04 +0900
Subject: [PATCH 16/18] add an internal capsule

---
 Include/datetime.h                          | 22 ++++++++++---
 Lib/test/datetimetester.py                  |  2 +-
 Modules/_datetimemodule.c                   | 34 +++++++++++++--------
 Modules/_testcapi/datetime.c                |  3 --
 Modules/_testmultiphase.c                   |  2 +-
 Tools/c-analyzer/cpython/globals-to-fix.tsv |  1 +
 6 files changed, 42 insertions(+), 22 deletions(-)

diff --git a/Include/datetime.h b/Include/datetime.h
index b023da24be35f6..cb79b1880fb756 100644
--- a/Include/datetime.h
+++ b/Include/datetime.h
@@ -186,16 +186,30 @@ typedef struct {
 } PyDateTime_CAPI;
 
 #define PyDateTime_CAPSULE_NAME "datetime.datetime_CAPI"
-
-PyAPI_FUNC(void) _PyDateTimeAPI_Import(void);
-PyAPI_FUNC(void) _PyDateTimeAPI_Clear(void);
-PyAPI_FUNC(PyDateTime_CAPI *) _PyDateTimeAPI_Get(void);
+#define PyDateTime_INTERNAL_CAPSULE_NAME "datetime.datetime_CAPI_INTERNAL"
 
 /* This block is only used as part of the public API and should not be
  * included in _datetimemodule.c, which does not use the C API capsule.
  * See bpo-35081 for more details.
  * */
 #ifndef _PY_DATETIME_IMPL
+static PyDateTime_CAPI *
+_PyDateTimeAPI_not_ready(void)
+{
+    return NULL;
+}
+typedef PyDateTime_CAPI *(*datetime_api_getfunc)(void);
+static datetime_api_getfunc _PyDateTimeAPI_Get = _PyDateTimeAPI_not_ready;
+
+static inline void
+_PyDateTimeAPI_Import(void)
+{
+    datetime_api_getfunc (*func)(void) = PyCapsule_Import(
+                                           PyDateTime_INTERNAL_CAPSULE_NAME, 0);
+    if (func) {
+        _PyDateTimeAPI_Get = func();
+    }
+}
 
 #define PyDateTimeAPI _PyDateTimeAPI_Get()
 #define PyDateTime_IMPORT _PyDateTimeAPI_Import()
diff --git a/Lib/test/datetimetester.py b/Lib/test/datetimetester.py
index 570110893629cf..6946b394e68a82 100644
--- a/Lib/test/datetimetester.py
+++ b/Lib/test/datetimetester.py
@@ -91,7 +91,7 @@ def test_name_cleanup(self):
                     if not name.startswith('__') and not name.endswith('__'))
         allowed = set(['MAXYEAR', 'MINYEAR', 'date', 'datetime',
                        'datetime_CAPI', 'time', 'timedelta', 'timezone',
-                       'tzinfo', 'UTC', 'sys'])
+                       'tzinfo', 'UTC', 'sys', 'datetime_CAPI_INTERNAL'])
         self.assertEqual(names - allowed, set([]))
 
     def test_divide_and_round(self):
diff --git a/Modules/_datetimemodule.c b/Modules/_datetimemodule.c
index 356956144d9865..16ec3bd61144e0 100644
--- a/Modules/_datetimemodule.c
+++ b/Modules/_datetimemodule.c
@@ -69,7 +69,13 @@ set_datetime_capi_by_interp(PyDateTime_CAPI *capi)
     _PyInterpreterState_GET()->datetime_capi = capi;
 }
 
-void
+static PyDateTime_CAPI *
+_PyDateTimeAPI_Get(void)
+{
+    return (PyDateTime_CAPI *)_PyInterpreterState_GET()->datetime_capi;
+}
+
+static void *
 _PyDateTimeAPI_Import(void)
 {
     PyDateTime_CAPI *capi = PyCapsule_Import(PyDateTime_CAPSULE_NAME, 0);
@@ -77,19 +83,9 @@ _PyDateTimeAPI_Import(void)
         // PyInit__datetime() is not called when the module is already loaded
         // with single-phase init.
         set_datetime_capi_by_interp(capi);
+        return _PyDateTimeAPI_Get;
     }
-}
-
-PyDateTime_CAPI *
-_PyDateTimeAPI_Get(void)
-{
-    return (PyDateTime_CAPI *)_PyInterpreterState_GET()->datetime_capi;
-}
-
-void
-_PyDateTimeAPI_Clear(void)
-{
-    set_datetime_capi_by_interp(NULL);
+    return NULL;
 }
 
 /* We require that C int be at least 32 bits, and use int virtually
@@ -6972,6 +6968,18 @@ _datetime_exec(PyObject *module)
         PyMem_Free(capi);
         goto error;
     }
+
+    capsule = PyCapsule_New(_PyDateTimeAPI_Import,
+                            PyDateTime_INTERNAL_CAPSULE_NAME, NULL);
+    if (capsule == NULL) {
+        PyMem_Free(capi);
+        goto error;
+    }
+    if (PyModule_Add(module, "datetime_CAPI_INTERNAL", capsule) < 0) {
+        PyMem_Free(capi);
+        goto error;
+    }
+
     /* Ensure that the newest capi is used on multi-phase init */
     set_datetime_capi_by_interp(capi);
 
diff --git a/Modules/_testcapi/datetime.c b/Modules/_testcapi/datetime.c
index 7050f492bfa745..b1796039f0d83a 100644
--- a/Modules/_testcapi/datetime.c
+++ b/Modules/_testcapi/datetime.c
@@ -8,9 +8,6 @@ static int test_run_counter = 0;
 static PyObject *
 test_datetime_capi(PyObject *self, PyObject *args)
 {
-    if (!test_run_counter) {
-        _PyDateTimeAPI_Clear();
-    }
     if (PyDateTimeAPI) {
         if (test_run_counter) {
             /* Probably regrtest.py -R */
diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index 6860fbddb59df4..429824fbede1fa 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -998,7 +998,7 @@ datetime_capi_import_with_error(void)
 static int
 datetime_capi_client_exec(PyObject *m)
 {
-    _PyDateTimeAPI_Clear();
+    _PyDateTimeAPI_Get = _PyDateTimeAPI_not_ready;
     if (_PyDateTimeAPI_Get() != NULL) {
         PyErr_SetString(PyExc_AssertionError,
                         "DateTime API is expected to remain NULL.");
diff --git a/Tools/c-analyzer/cpython/globals-to-fix.tsv b/Tools/c-analyzer/cpython/globals-to-fix.tsv
index ae6a579dae1b23..3c0f3b39530d3f 100644
--- a/Tools/c-analyzer/cpython/globals-to-fix.tsv
+++ b/Tools/c-analyzer/cpython/globals-to-fix.tsv
@@ -446,6 +446,7 @@ Modules/_tkinter.c	-	trbInCmd	-
 ## initialized once
 
 ## other
+Include/datetime.h	-	_PyDateTimeAPI_Get	-
 Modules/_ctypes/cfield.c	_ctypes_get_fielddesc	initialized	-
 Modules/_ctypes/malloc_closure.c	-	_pagesize	-
 Modules/_cursesmodule.c	-	initialised	-

From de31431d3c6560fb187dd11df5f66905a841515f Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Wed, 1 May 2024 19:19:45 +0900
Subject: [PATCH 17/18] remove typedef

---
 Include/datetime.h | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/Include/datetime.h b/Include/datetime.h
index cb79b1880fb756..54d80303a281ce 100644
--- a/Include/datetime.h
+++ b/Include/datetime.h
@@ -198,14 +198,12 @@ _PyDateTimeAPI_not_ready(void)
 {
     return NULL;
 }
-typedef PyDateTime_CAPI *(*datetime_api_getfunc)(void);
-static datetime_api_getfunc _PyDateTimeAPI_Get = _PyDateTimeAPI_not_ready;
+static PyDateTime_CAPI *(*_PyDateTimeAPI_Get)(void) = _PyDateTimeAPI_not_ready;
 
 static inline void
 _PyDateTimeAPI_Import(void)
 {
-    datetime_api_getfunc (*func)(void) = PyCapsule_Import(
-                                           PyDateTime_INTERNAL_CAPSULE_NAME, 0);
+    void *(*func)(void) = PyCapsule_Import(PyDateTime_INTERNAL_CAPSULE_NAME, 0);
     if (func) {
         _PyDateTimeAPI_Get = func();
     }

From 8dadc4929fb23602ac51aa932fb50f3bb42f4a24 Mon Sep 17 00:00:00 2001
From: neonene <53406459+neonene@users.noreply.github.com>
Date: Mon, 6 May 2024 00:54:13 +0900
Subject: [PATCH 18/18] add Py_MOD_GIL_NOT_USED to the test

---
 Modules/_testmultiphase.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/Modules/_testmultiphase.c b/Modules/_testmultiphase.c
index 4bb372058076aa..9d5263482360e3 100644
--- a/Modules/_testmultiphase.c
+++ b/Modules/_testmultiphase.c
@@ -994,7 +994,7 @@ datetime_capi_import_with_error(void)
     }
     if (is_datetime_multiphase < 0) {
         PyErr_SetString(PyExc_AssertionError,
-                        "Main interpreter must be loaded first.");
+                        "Main interpreter must be tested first.");
         return -1;
     }
 
@@ -1036,6 +1036,7 @@ datetime_capi_client_exec(PyObject *m)
 static PyModuleDef_Slot datetime_capi_client_slots[] = {
     {Py_mod_exec, datetime_capi_client_exec},
     {Py_mod_multiple_interpreters, Py_MOD_PER_INTERPRETER_GIL_SUPPORTED},
+    {Py_mod_gil, Py_MOD_GIL_NOT_USED},
     {0, NULL},
 };