Bug #742342: make Python stop segfaulting on infinitely-recursive reload()s. Fixed by patch #922167.
Backported from r54291.
diff --git a/Python/import.c b/Python/import.c
index 390f9e3..b62eeef 100644
--- a/Python/import.c
+++ b/Python/import.c
@@ -339,6 +339,25 @@
return Py_None;
}
+PyObject *
+PyImport_GetModulesReloading(void)
+{
+ PyInterpreterState *interp = PyThreadState_Get()->interp;
+ if (interp->modules_reloading == NULL)
+ Py_FatalError("PyImport_GetModuleDict: no modules_reloading dictionary!");
+ return interp->modules_reloading;
+}
+
+static void
+imp_modules_reloading_clear (void)
+{
+ PyInterpreterState *interp = PyThreadState_Get()->interp;
+ if (interp->modules_reloading == NULL)
+ return;
+ PyDict_Clear(interp->modules_reloading);
+ return;
+}
+
/* Helper for sys */
PyObject *
@@ -498,6 +517,7 @@
PyDict_Clear(modules);
interp->modules = NULL;
Py_DECREF(modules);
+ Py_CLEAR(interp->modules_reloading);
}
@@ -2400,8 +2420,9 @@
PyObject *
PyImport_ReloadModule(PyObject *m)
{
+ PyObject *modules_reloading = PyImport_GetModulesReloading();
PyObject *modules = PyImport_GetModuleDict();
- PyObject *path = NULL, *loader = NULL;
+ PyObject *path = NULL, *loader = NULL, *existing_m = NULL;
char *name, *subname;
char buf[MAXPATHLEN+1];
struct filedescr *fdp;
@@ -2422,20 +2443,30 @@
name);
return NULL;
}
+ if ((existing_m = PyDict_GetItemString(modules_reloading, name)) != NULL) {
+ /* Due to a recursive reload, this module is already being reloaded. */
+ Py_INCREF(existing_m);
+ return existing_m;
+ }
+ PyDict_SetItemString(modules_reloading, name, m);
+
subname = strrchr(name, '.');
if (subname == NULL)
subname = name;
else {
PyObject *parentname, *parent;
parentname = PyString_FromStringAndSize(name, (subname-name));
- if (parentname == NULL)
+ if (parentname == NULL) {
+ imp_modules_reloading_clear();
return NULL;
+ }
parent = PyDict_GetItem(modules, parentname);
if (parent == NULL) {
PyErr_Format(PyExc_ImportError,
"reload(): parent %.200s not in sys.modules",
PyString_AS_STRING(parentname));
Py_DECREF(parentname);
+ imp_modules_reloading_clear();
return NULL;
}
Py_DECREF(parentname);
@@ -2450,6 +2481,7 @@
if (fdp == NULL) {
Py_XDECREF(loader);
+ imp_modules_reloading_clear();
return NULL;
}
@@ -2466,6 +2498,7 @@
*/
PyDict_SetItemString(modules, name, m);
}
+ imp_modules_reloading_clear();
return newm;
}