I've tried to use a workspace's Custom Property as a variable for a Driver, but it looks like the path to the Custom Property is broken. Is there anything that needs to be added to the properties path?
Define the prop.
In as much as I agree with @DRF that using workspace properties as input into drivers is not a good idea...
Appears it is with custom properties, ie those defined via custom props panel or via script with
context.workspace["prop"] = 44.55
on the workspace that create the error. Trying instead the
users property of the workspace it "works" (ie doesn't throw the error) as a driver variable.
If in script a property is defined via
bpy.types.WorkSpace.prop = bpy.props.FloatProperty()
in which case can address it via
it will also work as a driver variable.
Since prop is stored as the custom property of same name will see the API defined message beside it.
Note: as mentioned this "works" as in it doesn't throw an error. It does however print warnings to the system console, and updating by pressing "Update dependencies" button.
Unhandled ID WSGeneral add_relation(RNA Target -> Driver) - Could not find op_from (RnaPathKey(id: WSGeneral, prop: 'prop')) add_relation(RNA Target -> Driver) - Failed, but op_to (OperationKey(type: PARAMETERS, component name: '', operation code: DRIVER, 'location')) was ok