PyPySide: Fix a crash with PyPy 7.3.10 and 7.3.11, amended

Whether _functools or functools is retrieved, it is possible
to modify that at runtime. We therefore need to do much more
error checking.

Task-number: PYSIDE-2264
Task-number: PYSIDE-535
Change-Id: I4ad73b1729e68eccdc22df88a8332e36e052e57c
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
(cherry picked from commit 5529853210de3e51b2ad3c636ebee4a4d77aa54e)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

4 files changed, 29 insertions, 15 deletions

diff --git a/sources/shiboken6/libshiboken/pep384impl.cpp b/sources/shiboken6/libshiboken/pep384impl.cpp
index b1a74778c..8d996a706 100644
--- a/sources/shiboken6/libshiboken/pep384impl.cpp
+++ b/sources/shiboken6/libshiboken/pep384impl.cpp
@@ -719,6 +719,31 @@ PepType_GetNameStr(PyTypeObject *type)
     return ret;
 }
 
+// PYSIDE-2264: Find the _functools or functools module and retrieve the
+//              partial function. This can be tampered with, check carefully.
+PyObject *
+Pep_GetPartialFunction(void)
+{
+    static bool initialized = false;
+    static PyObject *result{};
+    if (initialized) {
+        Py_INCREF(result);
+        return result;
+    }
+    auto *functools = PyImport_ImportModule("_functools");
+    if (!functools) {
+        PyErr_Clear();
+        functools = PyImport_ImportModule("functools");
+    }
+    if (!functools)
+        Py_FatalError("functools cannot be found");
+    result = PyObject_GetAttrString(functools, "partial");
+    if (!result || !PyCallable_Check(result))
+        Py_FatalError("partial not found or not a function");
+    initialized = true;
+    return result;
+}
+
 /*****************************************************************************
  *
  * Newly introduced convenience functions
diff --git a/sources/shiboken6/libshiboken/pep384impl.h b/sources/shiboken6/libshiboken/pep384impl.h
index df41712b1..05c9afab3 100644
--- a/sources/shiboken6/libshiboken/pep384impl.h
+++ b/sources/shiboken6/libshiboken/pep384impl.h
@@ -149,6 +149,8 @@ LIBSHIBOKEN_API void PepType_PFTP_delete(PySideQFlagsType *flagsType);
 // functions used everywhere
 LIBSHIBOKEN_API const char *PepType_GetNameStr(PyTypeObject *type);
 
+LIBSHIBOKEN_API PyObject *Pep_GetPartialFunction(void);
+
 /*****************************************************************************
  *
  * RESOLVED: pydebug.h
diff --git a/sources/shiboken6/libshiboken/sbkenum.cpp b/sources/shiboken6/libshiboken/sbkenum.cpp
index fb70a1c8f..212e6fb73 100644
--- a/sources/shiboken6/libshiboken/sbkenum.cpp
+++ b/sources/shiboken6/libshiboken/sbkenum.cpp
@@ -1065,18 +1065,11 @@ static PyObject *create_missing_func(PyObject *klass)
 {
     // When creating the class, memorize it in the missing function by
     // a partial function argument.
-#ifdef PYPY_VERSION
-    const char *functools_str = "functools";
-#else
-    const char *functools_str = "_functools";
-#endif
     static auto *const type = SbkType_FromSpec(&dummy_spec);
     static auto *const obType = reinterpret_cast<PyObject *>(type);
     static auto *const _missing = Shiboken::String::createStaticString("_missing_");
     static auto *const func = PyObject_GetAttr(obType, _missing);
-    static auto *const functools = PyImport_ImportModule(functools_str);   // builtin
-    static auto *const _partial = Shiboken::String::createStaticString("partial");
-    static auto *const partial = PyObject_GetAttr(functools, _partial);
+    static auto *const partial = Pep_GetPartialFunction();
     return PyObject_CallFunctionObjArgs(partial, func, klass, nullptr);
 }
 //
diff --git a/sources/shiboken6/libshiboken/sbkfeature_base.cpp b/sources/shiboken6/libshiboken/sbkfeature_base.cpp
index d732faa29..1242cbda4 100644
--- a/sources/shiboken6/libshiboken/sbkfeature_base.cpp
+++ b/sources/shiboken6/libshiboken/sbkfeature_base.cpp
@@ -178,13 +178,7 @@ void initEnumFlagsDict(PyTypeObject *type)
 
 static PyObject *replaceNoArgWithZero(PyObject *callable)
 {
-#ifdef PYPY_VERSION
-    const char *functools_str = "functools";
-#else
-    const char *functools_str = "_functools";
-#endif
-    static auto *functools = PyImport_ImportModule(functools_str);   // builtin
-    static auto *partial = PyObject_GetAttrString(functools, "partial");
+    static auto *partial = Pep_GetPartialFunction();
     static auto *zero = PyLong_FromLong(0);
     return PyObject_CallFunctionObjArgs(partial, callable, zero, nullptr);
 }