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Date: Wed, 11 Nov 2020 21:47:46 +0000
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Subject: Re: [PHP-DEV] strict_types will be default at some moment?
From: rowan.collins@gmail.com (Rowan Tommins)

On 11/11/2020 20:20, David Rodrigues wrote:
> I have been asked by a friend if declare(strict_types=1) will be applied by
> default for some version of PHP, like 9.x or will it be always required by
> all scripts forever. Someone can tell me?
>
> If yes, what is the reason for requiring it? Why it can't be the default
> behavior (or maybe, the unique behavior).


The question (which I hear often) misunderstands the original intent of 
the declaration, as I understand it: the strict_types switch was not 
designed as a transition mechanism for old code, it was designed as a 
genuine choice between two different options, both equally new.

Before PHP 7.0, there was no ability for a (user-defined) function to 
declare that it wanted an int, string, float, or boolean argument. When 
it was proposed that these "scalar type hints" be added, there were 
different, strongly held, opinions on how that should work, leading to 
at least 5 separate RFCs, several thousand mailing list posts, and a lot 
of general unhappiness.

The idea behind the strict_types directive was to combine two versions 
of the feature into one system, allowing users to switch between them at 
will. The proposal made clear that both modes have their advantages and 
disadvantages. A few of those were affected by compatibility with older 
code - in particular, around the behaviour of built-in functions - but 
those were not the main driving factors behind providing two modes.

Perhaps, 5 or 6 years on, things have changed. Certainly, there are a 
vocal community of users who see "strict_types=1" as unreservedly 
"better" in some fundamental way - but then, there always were, that's 
why the debate was so heated. I rather suspect that most of the 
arguments put forward for one position or the other then are just as 
true now.

I do wonder if people would even be asking the question, if the modes 
had been named something like "scalar_types=coerce" and 
"scalar_types=error", and somehow arranged such that neither was in 
force by default.


[PS: What a beautifully timed e-mail - "11/11/2020 20:20 UTC"!]


Regards,

-- 
Rowan Tommins (né Collins)
[IMSoP]