gh-102660: Handle m_copy Specially for the sys and builtins Modules (gh-102661)

It doesn't make sense to use multi-phase init for these modules. Using a per-interpreter "m_copy" (instead of PyModuleDef.m_base.m_copy) makes this work okay. (This came up while working on gh-101660.)

Note that we might instead end up disallowing re-load for sys/builtins since they are so special.

https://github.com/python/cpython/issues/102660

1 files changed, 8 insertions, 0 deletions

diff --git a/Python/sysmodule.c b/Python/sysmodule.c
index 764fb70bae..fc0550266b 100644
--- a/Python/sysmodule.c
+++ b/Python/sysmodule.c
@@ -3425,12 +3425,20 @@ _PySys_Create(PyThreadState *tstate, PyObject **sysmod_p)
         return _PyStatus_ERR("failed to create a module object");
     }
 
+    /* m_copy of Py_None means it is copied some other way. */
+    sysmodule.m_base.m_copy = Py_NewRef(Py_None);
+
     PyObject *sysdict = PyModule_GetDict(sysmod);
     if (sysdict == NULL) {
         goto error;
     }
     interp->sysdict = Py_NewRef(sysdict);
 
+    interp->sysdict_copy = PyDict_Copy(sysdict);
+    if (interp->sysdict_copy == NULL) {
+        goto error;
+    }
+
     if (PyDict_SetItemString(sysdict, "modules", modules) < 0) {
         goto error;
     }