mitsuhiko/flask — pull request #545 by yunfan (2012-07-11 06:45:43+00:00)
Title: a doubtful bug fix

this is a doubtful bug,

i found when i am trying to got the blueprint's url_prefix , it return none,
but i have give it a url_prefix in app initialization stage via register_blueprint

so i check the source code, and found the reason

the calling chain is that

app.register_blueprint(blueprint_instance, *kargs) -> blueprint_instance.register(**kargs)

and it will make a BlueprintSetupState object (called BSS)from these parameters ,

*IF* the blueprints object has some deferred_functions, it will handle the BSS for deferred processing

but in common user case, the dererred_functions is a empty list, so it would do nothing with the BSS

i know how it has been caused and how to fix it, but i dont know the design goal of flask, so i think
it is just a doubtful bug, maybe you guys has some reason for avoiding this update action if user dont provide a special deferred func