shiboken: Fix dict access without GIL

In PYSIDE-803 we used an optimization that accessed
a dictionary without holding the GIL. This turned out to be not
correct, because PyDict_GetItem works with thread state
to maintain the global error variables.

PyDict_GetItemWithErrors can be used instead in a way that
allows releasing the GIL.

Task-number: PYSIDE-803
Task-number: PYSIDE-813
Change-Id: Ifb0cbb20c21ca9c8b3d099fff1db5410eb6824b4
Reviewed-by: Christian Tismer <tismer@stackless.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/sources/pyside2/libpyside/signalmanager.cpp b/sources/pyside2/libpyside/signalmanager.cpp
index 01b347a3d..0fe0d0092 100644
--- a/sources/pyside2/libpyside/signalmanager.cpp
+++ b/sources/pyside2/libpyside/signalmanager.cpp
@@ -559,7 +559,10 @@ static MetaObjectBuilder *metaBuilderFromDict(PyObject *dict)
     if (!dict || !PyDict_Contains(dict, metaObjectAttr))
         return nullptr;
 
-    PyObject *pyBuilder = PyDict_GetItem(dict, metaObjectAttr);
+    // PYSIDE-813: The above assumption is not true in debug mode:
+    // PyDict_GetItem would touch PyThreadState_GET and the global error state.
+    // PyDict_GetItemWithError instead can work without GIL.
+    PyObject *pyBuilder = PyDict_GetItemWithError(dict, metaObjectAttr);
 #ifdef IS_PY3K
     return reinterpret_cast<MetaObjectBuilder *>(PyCapsule_GetPointer(pyBuilder, nullptr));
 #else