setup: fix PySide6.__all__ after the wheel split, amendment 3

The __all__ support for the PySide6 module works just fine.

But there is a last incompatibility that might strike others
as it did hit ourselves when using PySide6.__dict["__all__"]:

Use a derived dict type and define a __missing__ attribute.
Derive further a module type, then it works without problems.
A little support function in Shiboken allows to replace the
dict of PySide6 with this derived type.

amends 703d975.

Pick-to: 6.8
Task-number: PYSIDE-2895
Task-number: PYSIDE-1890
Change-Id: I018228116a5fdd1401c1ebd42ceb886f6829deeb
Reviewed-by: Christian Tismer <[email protected]>

Author: ctismer

sources/pyside6/PySide6/__init__.py.in

@@ -1,6 +1,8 @@
 import os
 import sys
 from pathlib import Path
+from types import ModuleType
+# mypy: disable-error-code="name-defined"
 
 # __all__ is computed below.
 __pre_all__ = [@init_modules@]
@@ -60,6 +62,7 @@ def _setupQtDirectories():
     try:
         # PYSIDE-1497: we use the build dir or install dir or site-packages, whatever the path
         #              setting dictates. There is no longer a difference in path structure.
+        global Shiboken
         from shiboken6 import Shiboken
     except Exception:
         paths = ', '.join(sys.path)
@@ -121,4 +124,18 @@ def __getattr__(name: str) -> list[str]:
     raise AttributeError(f"module '{__name__}' has no attribute '{name}' :)")
 
 
+# Be prepared that people can access the module dict instead.
+class ModuleDict(dict):
+    def __missing__(self, key):
+        if key == "__all__":
+            self[key] = __all__ if "__all__" in globals() else __getattr__("__all__")
+            return __all__
+        raise KeyError(f"dict of module '{__name__}' has no key '{key}' :)")
+
+
+class SubModule(ModuleType):
+    pass
+
+
 _setupQtDirectories()
+Shiboken.replaceModuleDict(sys.modules["PySide6"], SubModule, ModuleDict(globals()))

sources/pyside6/tests/pysidetest/all_modules_load_test.py

@@ -13,18 +13,26 @@
 
 import PySide6
 
+
 # Note:
 # "from PySide6 import *" can only be used at module level.
 # It is also really not recommended to use. But for testing,
 # the "__all__" variable is a great feature!
-
-
 class AllModulesImportTest(unittest.TestCase):
     def testAllModulesCanImport(self):
         # would also work: exec("from PySide6 import *")
         for name in PySide6.__all__:
             exec(f"import PySide6.{name}")
 
+    def testAllReappearsAfterDel(self):
+        # This is the only incompatibility that remains:
+        # After __all__ is deleted, it will re-appear.
+        PySide6.__all__ = 42
+        self.assertEqual(PySide6.__dict__["__all__"], 42)
+        del PySide6.__all__
+        self.assertTrue(PySide6.__dict__["__all__"])
+        self.assertNotEqual(PySide6.__dict__["__all__"], 42)
+
 
 if __name__ == '__main__':
     unittest.main()

sources/shiboken6/libshiboken/sbkmodule.cpp

@@ -539,4 +539,29 @@ SbkConverter **getTypeConverters(PyObject *module)
     return (iter == moduleConverters.end()) ? 0 : iter->second;
 }
 
+// Replace the dictionary of a module by a different dict.
+// The dict should be filled with the content of the old dict, before.
+// Reason: Creating a module dict with __missing__ support.
+typedef struct {
+    PyObject_HEAD
+    PyObject *md_dict;
+} StartOf_PyModuleObject;
+
+bool replaceModuleDict(PyObject *module, PyObject *modClass, PyObject *dict)
+{
+    if (!(PyModule_Check(module) && PyType_Check(modClass) && PyDict_Check(dict)))
+        return false;
+    auto *modict = PyModule_GetDict(module);
+    auto *modIntern = reinterpret_cast<StartOf_PyModuleObject *>(module);
+    if (modict != modIntern->md_dict)
+        Py_FatalError("The layout of modules is incompatible");
+    auto *hold = modIntern->md_dict;
+    modIntern->md_dict = dict;
+    Py_INCREF(dict);
+    Py_DECREF(hold);
+    Py_INCREF(modClass);
+    module->ob_type = reinterpret_cast<PyTypeObject *>(modClass);
+    return true;
+}
+
 } } // namespace Shiboken::Module

sources/shiboken6/libshiboken/sbkmodule.h

@@ -84,6 +84,11 @@ LIBSHIBOKEN_API void registerTypeConverters(PyObject *module, SbkConverter **con
  */
 LIBSHIBOKEN_API SbkConverter **getTypeConverters(PyObject *module);
 
+/**
+ *  Replace the dictionary of a module. This allows to use `__missing__`.
+ */
+LIBSHIBOKEN_API bool replaceModuleDict(PyObject *module, PyObject *modClass, PyObject *dict);
+
 } // namespace Shiboken::Module
 
 #endif // SBK_MODULE_H

sources/shiboken6/shibokenmodule/shibokenmodule.cpp

@@ -75,6 +75,11 @@ if (!Shiboken::Object::checkType(%1)) {
 }
 // @snippet dump
 
+// @snippet replacemoduledict
+const bool ok = Shiboken::Module::replaceModuleDict(%1, %2, %3);
+%PYARG_0 = %CONVERTTOPYTHON[bool](ok);
+// @snippet replacemoduledict
+
 // @snippet getallvalidwrappers
 const auto setAll = Shiboken::BindingManager::instance().getAllPyObjects();
 PyObject* listAll = PyList_New(0);

sources/shiboken6/shibokenmodule/typesystem_shiboken.xml

@@ -41,6 +41,10 @@
         <inject-code file="shibokenmodule.cpp" snippet="disassembleframe"/>
     </add-function>
 
+    <add-function signature="replaceModuleDict(PyObject*, PyObject*, PyObject*)" return-type="bool">
+        <inject-code file="shibokenmodule.cpp" snippet="replacemoduledict"/>
+    </add-function>
+
     <add-function signature="dump(PyObject*)" return-type="const char *">
         <inject-code file="shibokenmodule.cpp" snippet="dump"/>
     </add-function>