using before and after update callback simultaneously on the same table

[黄祥]

is it possible to using before and after update callback simultaneously on the same table? tested before but got an error traceback

e.g.

def __before_update_order(s, f):

query = (db.product.id == 1)

db(query).update(quantity = 9)

def __after_update_order(s, f):

if not ('is_active' in f and f['is_active'] == False):

s.update(notes = 'test')

db.order._before_update.append(__before_update_order)

db.order._after_update.append(__after_update_order)

return an error traceback :

RuntimeError: maximum recursion depth exceeded while calling a Python object

thanks and best regards,

stifan

[Leonel Câmara]

It's possible, but not if they're doing what yours are.

Namely the problem here is not that you have a before and after update callback. The problem is your __after_update_order. Your __after_update_order updates table order which triggers __after_update_order again. This would be ok if you had a condition that would terminate the recursion which you don't,  

Lets see what happens when s.update(notes='test') runs. This is an update where 'is_active' is not in f so it will trigger s.update(notes='test') again. And again. And again.  

[黄祥]

thanks leonel for the hints, find the solution with update_naive, because the logic for the real code is to recalculate the order table when it's update

e.g. use update_naive

def __after_update_order(s, f):

if not ('is_active' in f and f['is_active'] == False):

s.update_naive(notes = 'test')

from the book

For this purpose there the Set objects have an update_naive method that works like update but ignores before and after callbacks.

is there any side effect for this? tested it works smoothly, perhaps i can use compute function for that