diff options
author | Christian Tismer <tismer@stackless.com> | 2018-03-23 19:54:42 +0100 |
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committer | Christian Tismer <tismer@stackless.com> | 2018-04-19 11:20:51 +0000 |
commit | a89690409972501741c846ac8ad4a499f2982809 (patch) | |
tree | 7684abfa34b4c9aa66ab317452da37ccc1f8f31e /sources/shiboken2/libshiboken | |
parent | 4023ab3862eee7ca3084dd83ca76fba11b5db46b (diff) |
fix more qApp crashes
When building PySide with a debug Python, a lot more problems
become visible.
They were triggered by some malicious ordering of the shutdown code,
which must come *after* the refcounts of the variables are adjusted.
The initial issue PYSIDE-585 was caused because the shutdown code
is not only used for every created Q*Application, but also for the
module shutdown, which deletes qApp_contents too often.
Instead of special-casing that or adding some refcount, it was much
more intuitive in that context to set qApp_content's refcount to the
same value as Py_None, which also is not supposed to be garbage
collected.
Btw., the reason for the error message is that Py_None has it, too.
When we set qApp_content's type to Py_None's type, it inherits
the protection code that prevents someone from garbage collecting
Py_None.
Task-number: PYSIDE-585
Change-Id: I4af9de1192730f06054a5aca099a32e2392e367d
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Diffstat (limited to 'sources/shiboken2/libshiboken')
-rw-r--r-- | sources/shiboken2/libshiboken/qapp_macro.cpp | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/sources/shiboken2/libshiboken/qapp_macro.cpp b/sources/shiboken2/libshiboken/qapp_macro.cpp index 9b940aaaa..e3f23de4f 100644 --- a/sources/shiboken2/libshiboken/qapp_macro.cpp +++ b/sources/shiboken2/libshiboken/qapp_macro.cpp @@ -105,7 +105,14 @@ reset_qApp_var() return 0; } - +/* + * Note: + * The PYSIDE-585 problem was that shutdown is called one more often + * than Q*Application is created. We could special-case that last + * shutdown or add a refcount, initially, but actually it was easier + * and more intuitive in that context to make the refcount of + * qApp_content equal to the refcount of Py_None. + */ PyObject * MakeSingletonQAppWrapper(PyTypeObject *type) { @@ -132,15 +139,16 @@ MakeSingletonQAppWrapper(PyTypeObject *type) // Debug mode showed that we need to do more than just remove the // reference. To keep everything in the right order, it is easiest // to do a full shutdown, using QtCore.__moduleShutdown(). + // restore the "None-state" PyObject *__moduleShutdown = PyDict_GetItemString(qApp_moduledicts[1], "__moduleShutdown"); - if (__moduleShutdown != NULL) { - Py_DECREF(PyObject_CallFunction(__moduleShutdown, (char *)"()")); - } - // restore the "None-state" + // PYSIDE-585: It was crucial to update the refcounts *before* + // calling the shutdown. Py_TYPE(qApp_content) = Py_NONE_TYPE; Py_REFCNT(qApp_var) = qApp_var_ref; - Py_REFCNT(qApp_content) = qApp_content_ref; + Py_REFCNT(qApp_content) = Py_REFCNT(Py_None); + if (__moduleShutdown != NULL) + Py_DECREF(PyObject_CallFunction(__moduleShutdown, (char *)"()")); } else (void)PyObject_INIT(qApp_content, type); @@ -160,7 +168,7 @@ setup_qApp_var(PyObject *module) return -1; // This is a borrowed reference qApp_moduledicts[0] = PyEval_GetBuiltins(); - Py_INCREF(qApp_content); + Py_INCREF(qApp_moduledicts[0]); init_done = 1; } @@ -170,7 +178,7 @@ setup_qApp_var(PyObject *module) if (module_index) { // This line gets a borrowed reference qApp_moduledicts[module_index] = PyModule_GetDict(module); - Py_INCREF(qApp_content); + Py_INCREF(qApp_moduledicts[module_index]); if (reset_qApp_var() < 0) return -1; } |