[3.14] pythongh-140306: Fix memory leaks in cross-interpreter data handling (pythonGH-140307) (pythonGH-140338)

(cherry picked from commit f932321)

Co-authored-by: Shamil <[email protected]>

Author: miss-islington

Misc/NEWS.d/next/Core_and_Builtins/2025-10-18-21-29-45.gh-issue-140306.xS5CcS.rst

@@ -0,0 +1,2 @@
+Fix memory leaks in cross-interpreter channel operations and shared
+namespace handling.

Modules/_interpchannelsmodule.c

@@ -580,7 +580,7 @@ _channelitem_clear_data(_channelitem *item, int removed)
 {
     if (item->data != NULL) {
         // It was allocated in channel_send().
-        (void)_release_xid_data(item->data, XID_IGNORE_EXC & XID_FREE);
+        (void)_release_xid_data(item->data, XID_IGNORE_EXC | XID_FREE);
         item->data = NULL;
     }
 

Modules/_interpqueuesmodule.c

@@ -431,7 +431,7 @@ _queueitem_clear_data(_queueitem *item)
         return;
     }
     // It was allocated in queue_put().
-    (void)_release_xid_data(item->data, XID_IGNORE_EXC & XID_FREE);
+    (void)_release_xid_data(item->data, XID_IGNORE_EXC | XID_FREE);
     item->data = NULL;
 }
 

Python/crossinterp.c

@@ -1153,8 +1153,8 @@ _release_xid_data(_PyXIData_t *xidata, int rawfree)
 {
     PyObject *exc = PyErr_GetRaisedException();
     int res = rawfree
-        ? _PyXIData_Release(xidata)
-        : _PyXIData_ReleaseAndRawFree(xidata);
+        ? _PyXIData_ReleaseAndRawFree(xidata)
+        : _PyXIData_Release(xidata);
     if (res < 0) {
         /* The owning interpreter is already destroyed. */
         _PyXIData_Clear(NULL, xidata);
@@ -1805,6 +1805,15 @@ _PyXI_InitFailureUTF8(_PyXI_failure *failure,
 int
 _PyXI_InitFailure(_PyXI_failure *failure, _PyXI_errcode code, PyObject *obj)
 {
+    *failure = (_PyXI_failure){
+        .code = code,
+        .msg = NULL,
+        .msg_owned = 0,
+    };
+    if (obj == NULL) {
+        return 0;
+    }
+
     PyObject *msgobj = PyObject_Str(obj);
     if (msgobj == NULL) {
         return -1;
@@ -1813,7 +1822,7 @@ _PyXI_InitFailure(_PyXI_failure *failure, _PyXI_errcode code, PyObject *obj)
     // That happens automatically in _capture_current_exception().
     const char *msg = _copy_string_obj_raw(msgobj, NULL);
     Py_DECREF(msgobj);
-    if (PyErr_Occurred()) {
+    if (msg == NULL) {
         return -1;
     }
     *failure = (_PyXI_failure){