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Date: Wed, 24 Sep 2014 22:49:36 +0100
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Subject: Re: [PHP-DEV] [RFC] ZPP Failure On Overflow
From: rowan.collins@gmail.com (Rowan Collins)

On 24/09/2014 18:40, Stas Malyshev wrote:
>>> That said, most cases of "garbage in, garbage out" would presumably
>>> remain so, since most ZPP failures result in a return of NULL or
>>> FALSE, which would probably end up cast back to the expected type
>>> (int(0), string(''), etc) by the surrounding code.
>> Right. It’s not an E_RECOVERABLE_ERROR, you’d just get an E_WARNING.
> No, you'd get E_WARNING *and* function would not run. Where before it
> did run. That is the problem, not the warning - you add more cases where
> the function does not run when it did before, and that can have profound
> consequences on the code that depends on it.

So, the problem comes with built-in functions, which have some side 
effect, which can be usefully run with a bogus value for an integer 
argument. In contrast, any function which has some side effect which is 
actively harmful given a bogus value would be a beneficiary of the change.

A function with no side effects will simply go from "garbage in, garbage 
out" to "garbage in, NULL out".

I wonder how many functions actually fall into each category.

-- 
Rowan Collins
[IMSoP]