InstructionQuotaExceeded - customers creating very large carts...

[rancet]

I have just released some new cart script code to implement multibuy discounts - I tested it thoroughly and its working well.

Some customers are causing "InstructionQuotaExceeded" errors by entering huge carts (many lines, order 1 million items).  The code loops through the cart lines finding deals so carts of this size won't process due to CPU limits.

Operationally, its not causing a problem, because the carts never goto checkout & the cart just ends up unmodified.

However, I am getting email notifications each time this happens & I like my script to detect error conditions rather than run with errors...

I am planning to deal with it by detecting a max cart size/items which if exceed the cart script exits.  

I am interested whether anyone else has experienced similar problems & what strategies have you employed to deal with it?