> I still don't understand this logic. If my code is written so that it
> needs the current "same namespace fallback to global" behaviour, I don't
> care what the default mode is, or how many other modes there are, I want
> to make sure that file will continue to use that mode. The *only* way to
> do that is if there is a directive saying *explicitly* that I want that
> mode.
>
> In other words, we don't need to know what the future modes are to know
what modes we have *right now*, and give those modes names.

If strict_types had a name instead of a number, we'd have a similar argument
over whether there should be a `strict_types='off'` vs `='default'`
and `strict_types='on'`

`'default'` is the option I'd consider the best for what I consider to be
likely ways php will/won't change. I can

> I'm not seeing the downside of adding it now.

- Confusion by new developers over whether `'fallback'` is weaker than omitting 
the option.
- Obliging future maintainers to potentially support whatever `'fallback'` 
would be understood to be
  if PHP's name resolution changes in a minor way.
  (e.g. if `count()` uses a keyword that's always the global function, like 
`empty()` currently does, as an unrealistic/undesirable example)

> The difference is that we could change the default in a future version
> to be strict_types=1, and people could run code with strict_types=0 on
> both versions with exactly the same effects. That's not the same as
> saying strict_types='default'.

If php changes the default casting behavior to forbid weak casting boolean to 
string
or string to boolean (as another unrealistic example), I personally wouldn't 
expect strict_types=0 to be required to allow it.
In that case, both versions wouldn't have the same effects.
Discussions on such a change may reasonably differ in those expectations.

> > I doubt that there would be an argument for creating `strict_types='php7'` 
> > before we knew what those changes are,
>
> We already have created that: strict_types=0 and strict_types=1 can
> retain their current meaning, and any new mode can have a new name
> (strict_types=2, strict_types='php9', whatever).
>
>
> To be clear, I'm not suggesting 'fallback' is added as a third option,
> I'm saying we should name the two options 'fallback' and 'global', just
> like strict_types has two options, 0 and 1. I can't think of any
> situation where I would want a change to the default mode in the engine
> to cause my code to be interpreted in a different way, so a 'default'
> option makes no sense to me.

I have a better understanding of why you're asking for this now,
but still prefer 'default' and 'global' for the reasons I've mentioned.

________________________________________
From: Rowan Tommins <rowan.coll...@gmail.com>
Sent: January 28, 2020 4:06 AM
To: internals@lists.php.net
Subject: Re: [PHP-DEV] [RFC] "use global functions/consts" statement

On 28/01/2020 01:06, tyson andre wrote:
> I don't plan to change the default name resolution behavior in PHP 9, though,
> and if it does change, it might even be according to a different proposal,
> so adding 'fallback' as a third option before we know what type of change is 
> planned
> seems premature.


I still don't understand this logic. If my code is written so that it
needs the current "same namespace fallback to global" behaviour, I don't
care what the default mode is, or how many other modes there are, I want
to make sure that file will continue to use that mode. The *only* way to
do that is if there is a directive saying *explicitly* that I want that
mode.

In other words, we don't need to know what the future modes are to know
what modes we have *right now*, and give those modes names.


> I'd imagine the migration to 8.0 and 9.0 would be similar to 5.6 to 7.0


That's not the point; people want to be able to run the same code on
multiple versions; the sooner we include a forwards-compatible option,
the more versions code referencing that option can run on. I'm not
seeing the downside of adding it now.


> I see `strict_types=0` as similar - The value `0` is currently rarely used 
> compared to leaving out the setting.
> If php 8.x were to become stricter about type casting by default in a few 
> ways,


The difference is that we could change the default in a future version
to be strict_types=1, and people could run code with strict_types=0 on
both versions with exactly the same effects. That's not the same as
saying strict_types='default'.


> I doubt that there would be an argument for creating `strict_types='php7'` 
> before we knew what those changes are,


We already have created that: strict_types=0 and strict_types=1 can
retain their current meaning, and any new mode can have a new name
(strict_types=2, strict_types='php9', whatever).


To be clear, I'm not suggesting 'fallback' is added as a third option,
I'm saying we should name the two options 'fallback' and 'global', just
like strict_types has two options, 0 and 1. I can't think of any
situation where I would want a change to the default mode in the engine
to cause my code to be interpreted in a different way, so a 'default'
option makes no sense to me.


Regards,

--
Rowan Tommins (né Collins)
[IMSoP]

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