for occurrence classes without special type.
E.g. previously:
you select IfcSlab and change it to IfcRoof - since there is not IfcRoofType in IFC2X3 it would figure the matching product type is IfcBeamType and change this slab's type element to IfcBeamType. IfcBuildingElementProxyType seems more generic and fitting.
E.g. you select IfcSlab and change it to IfcRoof - since there is not IfcRoofType in IFC2X3 it would figure the matching product type is IfcBeamType (which is confusing too but that's another subject) and change this slab's type object to IfcBeamType which consequently change IfcSlab to IfcBeam instead of IfcRoof that was selected originally.
Noticed investigating #5918
Previously, changing props.ifc_file had an update hook to reload
information about the IFC model. But this isn't always correct because
there are two situations:
1. The ifc_file path changed because you saved the file for the first
time or saved as, and this is merely recording a new saved path of the
existing file object.
2. The ifc_file path changed because the user manually changed it or
selected a new file. This could reference an entirely new file object.
This is dangerous because we can't trust anything anymore, including our
undo history.
So the new default situation is that there is no magic hook. If you
change props.ifc_file, that's all it changes ... just a path stored in
Blender with not much significance.
If the user runs select_ifc_file to explicitly relink the file, it now
explicitly purges in that situation and clears the undo history.
Basically now behaviour is explicit, not using magic hooks.
We had Chinese translation for Bonsai and some stub file for German and translation.py generation was failing with the error below. Chinese translation is more recent so it has some keys that German file hadn't and some keys were gone in the more recent version. In theory we should make all .po file in sync but let's skip it for now to keep things going.
```
Traceback (most recent call last):
File "/home/runner/work/IfcOpenShell/IfcOpenShell/src/bonsai/scripts/bonsai_translations.py", line 379, in <module>
update_translations_from_po(po_directory=Path(args.input), translations_module=Path(args.output))
File "/home/runner/work/IfcOpenShell/IfcOpenShell/src/bonsai/scripts/bonsai_translations.py", line 203, in update_translations_from_po
if (msgstr := msg.translations[lang]) in (None, ""):
~~~~~~~~~~~~~~~~^^^^^^
KeyError: 'de_DE'
```
Andrej730