__feature__: Make imports more safe against installation errors

PySide is sometimes installed by modified installer scripts.

The __feature__ script may be problematic due to dunder usage.
We therefore remove dunder and use it internally, only.

The __feature__ also has a problem with PyInstaller (maybe solved
by the above) and does not work. But if somebody did an omission,
a false error message can be generated.

As a cure, we explicitly test the import of PySide6.support before
we import the pseudo module PySide6.support.__feature__ . This is
an unconditional error, while a missing feature import is just
a warning.

Task-number: PYSIDE-1502
Change-Id: Ia4feaa67b615581291d1c7ff0c5fbdf40a2f176f
Pick-to: 5.15
Reviewed-by: Christian Tismer <tismer@stackless.com>

1 files changed, 10 insertions, 3 deletions

diff --git a/sources/shiboken6/shibokenmodule/files.dir/shibokensupport/signature/loader.py b/sources/shiboken6/shibokenmodule/files.dir/shibokensupport/signature/loader.py
index e685da166..9313cb663 100644
--- a/sources/shiboken6/shibokenmodule/files.dir/shibokensupport/signature/loader.py
+++ b/sources/shiboken6/shibokenmodule/files.dir/shibokensupport/signature/loader.py
@@ -112,7 +112,7 @@ def finish_import(module):
 
 
 import signature_bootstrap
-from shibokensupport import signature, __feature__
+from shibokensupport import signature, feature as __feature__
 signature.get_signature = signature_bootstrap.get_signature
 # PYSIDE-1019: Publish the __feature__ dictionary.
 __feature__.pyside_feature_dict = signature_bootstrap.pyside_feature_dict
@@ -176,7 +176,7 @@ def move_into_pyside_package():
         import PySide6.support
     except ModuleNotFoundError:
         PySide6.support = types.ModuleType("PySide6.support")
-    put_into_package(PySide6.support, __feature__)
+    put_into_package(PySide6.support, __feature__, "__feature__")
     put_into_package(PySide6.support, signature)
     put_into_package(PySide6.support.signature, mapping)
     put_into_package(PySide6.support.signature, errorhandler)
@@ -200,6 +200,13 @@ from shibokensupport.signature.lib import enum_sig
 if "PySide6" in sys.modules:
     # We publish everything under "PySide6.support.signature", again.
     move_into_pyside_package()
+    # PYSIDE-1502: Make sure that support can be imported.
+    try:
+        import PySide6.support
+    except ModuleNotFoundError as e:
+        print("PySide6.support could not be imported. "
+              "This is a serious configuration error.", file=sys.stderr)
+        raise e from None
     # PYSIDE-1019: Modify `__import__` to be `__feature__` aware.
     # __feature__ is already in sys.modules, so this is actually no import
     try:
@@ -210,6 +217,6 @@ if "PySide6" in sys.modules:
         # Maybe we should optimize that and change `__import__` from C, instead?
     except ModuleNotFoundError:
         print("__feature__ could not be imported. "
-              "This is an unsolved PyInstaller problem.", file=sys.stderr)
+              "This may be an unsolved PyInstaller problem.", file=sys.stderr)
 
 # end of file