From cdd663c58847eced4c810b05edda251c70a10438 Mon Sep 17 00:00:00 2001
From: shadchin <shadchin@yandex-team.com>
Date: Thu, 7 May 2026 07:27:37 +0300
Subject: Update Python 3 to 3.13.13
 commit_hash:526db1f6570443324e2690db042314848cd47d2e

---
 contrib/tools/python3/Python/import.c | 60 +++++++++++++++++++++++++++++++++--
 1 file changed, 58 insertions(+), 2 deletions(-)

(limited to 'contrib/tools/python3/Python/import.c')

diff --git a/contrib/tools/python3/Python/import.c b/contrib/tools/python3/Python/import.c
index 03a49ea0599..456f6c40b54 100644
--- a/contrib/tools/python3/Python/import.c
+++ b/contrib/tools/python3/Python/import.c
@@ -252,12 +252,32 @@ PyImport_GetModule(PyObject *name)
     mod = import_get_module(tstate, name);
     if (mod != NULL && mod != Py_None) {
         if (import_ensure_initialized(tstate->interp, mod, name) < 0) {
+            goto error;
+        }
+        /* Verify the module is still in sys.modules. Another thread may have
+           removed it (due to import failure) between our import_get_module()
+           call and the _initializing check in import_ensure_initialized(). */
+        PyObject *mod_check = import_get_module(tstate, name);
+        if (mod_check != mod) {
+            Py_XDECREF(mod_check);
+            if (_PyErr_Occurred(tstate)) {
+                goto error;
+            }
+            /* The module was removed or replaced. Return NULL to report
+               "not found" rather than trying to keep up with racing
+               modifications to sys.modules; returning the new value would
+               require looping to redo the ensure_initialized check. */
             Py_DECREF(mod);
-            remove_importlib_frames(tstate);
             return NULL;
         }
+        Py_DECREF(mod_check);
     }
     return mod;
+
+error:
+    Py_DECREF(mod);
+    remove_importlib_frames(tstate);
+    return NULL;
 }
 
 /* Get the module object corresponding to a module name.
@@ -2069,13 +2089,29 @@ import_run_extension(PyThreadState *tstate, PyModInitFunction p0,
     }
 
 main_finally:
+    if (rc < 0) {
+        _Py_ext_module_loader_result_apply_error(&res, name_buf);
+    }
+
     /* Switch back to the subinterpreter. */
     if (switched) {
+        // gh-144601: The exception object can't be transferred across
+        // interpreters. Instead, we print out an unraisable exception, and
+        // then raise a different exception for the calling interpreter.
+        if (rc < 0) {
+            assert(PyErr_Occurred());
+            PyErr_FormatUnraisable("Exception while importing from subinterpreter");
+        }
         assert(main_tstate != tstate);
         switch_back_from_main_interpreter(tstate, main_tstate, mod);
         /* Any module we got from the init function will have to be
          * reloaded in the subinterpreter. */
         mod = NULL;
+        if (rc < 0) {
+            PyErr_SetString(PyExc_ImportError,
+                            "failed to import from subinterpreter due to exception");
+            goto error;
+        }
     }
 
     /*****************************************************************/
@@ -2084,7 +2120,6 @@ main_finally:
 
     /* Finally we handle the error return from _PyImport_RunModInitFunc(). */
     if (rc < 0) {
-        _Py_ext_module_loader_result_apply_error(&res, name_buf);
         goto error;
     }
 
@@ -3789,6 +3824,27 @@ PyImport_ImportModuleLevelObject(PyObject *name, PyObject *globals,
         if (import_ensure_initialized(tstate->interp, mod, abs_name) < 0) {
             goto error;
         }
+        /* Verify the module is still in sys.modules. Another thread may have
+           removed it (due to import failure) between our import_get_module()
+           call and the _initializing check in import_ensure_initialized().
+           If removed, we retry the import to preserve normal semantics: the
+           caller gets the exception from the actual import failure rather
+           than a synthetic error. */
+        PyObject *mod_check = import_get_module(tstate, abs_name);
+        if (mod_check != mod) {
+            Py_XDECREF(mod_check);
+            if (_PyErr_Occurred(tstate)) {
+                goto error;
+            }
+            Py_DECREF(mod);
+            mod = import_find_and_load(tstate, abs_name);
+            if (mod == NULL) {
+                goto error;
+            }
+        }
+        else {
+            Py_DECREF(mod_check);
+        }
     }
     else {
         Py_XDECREF(mod);
-- 
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