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Date: Sat, 24 Feb 2024 01:37:51 +0000
To: PHP internals <internals@lists.php.net>
Subject: [PHP-DEV] [Pre-RFC] Convert exit (and die) from language constructs to functions
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From: internals@gpb.moe ("Gina P. Banyard")

Hello internals,

I've been having this mild annoyance with exit()/die() since I wrote a CLI
script using a boolean $hasErrors variable to know if the script failed or =
not
and to indicate if the script failed via a non-zero status code by doing:
exit($hasErrors);

However, it turns this doesn't work, because exit() will cast everything
that is not an integer to a string, something that I find surprising but
also weird as it will not type error on resources or array but rather print
the warning to the CLI.

Anyway, yesterday I decided to put on my mad scientist lab coat and make th=
is
a reality, I have a W.I.P. PR here:
https://github.com/php/php-src/pull/13483

I hear you, but what about exit; ?!
Do not worry exit; is still supported!
It only requires a _tiny_ bit of dark magic to achieve this!
exit; would just be interpreted as a fetch to a constant,
so when attempting to access the undefined exit/die case-insensitive consta=
nt
we just need to exit as if we were calling the function!

Having exit and die be functions gives us access to some interesting
functionality, such as defining exit() in a namespace, or removing it via t=
he
disable_functions INI setting (the latter allowing us to define a custom gl=
obal
exit() which could be useful for testing that a function actually calls exi=
t).

We can also pass it like any other callable and reflect on it with reflecti=
on.

Finally, this removes the T_EXIT token and ZEND_EXIT opcode freeing one slo=
t.

The W.I.P. PR implement every possible restriction:
 - not being able to declare an exit()/die() function
 - not being able to disable them
 - not being able to define a constant named exit/die

Maybe it would be wise to deprecate using exit as a statement to be able to=
 get
rid of the undefined constant magic handling.

Anyhoot, before I spend more time on this and write a proper RFC, do people
think this is a good idea or not?


Best regards,

Gina P. Banyard