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Date: Mon, 19 Sep 2016 13:04:48 +0000
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Subject: RFC: Strict comparisons
From: vpkaihla@gmail.com (Vesa Kaihlavirta)

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Hey all,

I've been bouncing this idea of fixing all comparison operations in one
fell swoop, although with an opt-in declare in the spirit of strict_types.

Here's the gist: ==, < and > plus all the comparisons done inside switch
statements and arrays are not very safe. === helps some, but does nothing
for switches and < >.

My idea is to add a strict_comparisons declaration that you can add at the
beginning of a file in the same way as strict_types. The effect would be
that all normal comparisons would make a type check before doing the actual
comparison, and throw a TypeError exception if the types don't match.

In other words:

<?php declare(strict_comparisons=1);

$two = "2";
if ($two > 1) {
        echo "This sorta works without strict_comparisons=1" . PHP_EOL;
}

...would throw a TypeError exception after this change.

This change would mostly go into zend_operators.c compare_function. So it
would affect every comparison operation, including switch statements and
things like in_array.

I've implemented a prototype with a couple of test cases in
https://github.com/paytrail/php-src/tree/experimental/strict_comparisons


Please take a look and let me know if this would be worth a more official
RFC.
<https://github.com/paytrail/php-src>
--vk

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