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Message-ID: <70E24D44-D791-4AEB-92C3-3B8C9579F5CC@cschneid.com>
Date: Sat, 16 Jan 2021 18:07:27 +0100
To: PHP internals <internals@lists.php.net>
Subject: Consistent type errors for internal functions and BC breaks
From: cschneid@cschneid.com (Christian Schneider)

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While testing the migration of our site to PHP 8 we noticed the BC break =
in internal functions like round() for parameter type errors:
round("foo") used to (silently, without warning) cast to float and =
return 0 where as now it throws a TypeError: round():
	https://3v4l.org/pU0LD

The RFC at =
https://wiki.php.net/rfc/consistent_type_errors#backward_incompatible_chan=
ges <https://wiki.php.net/rfc/consistent_type_errors> states
> Backward Incompatible Changes
>=20
> A TypeError will be thrown instead of a warning if incorrectly typed =
parameters are passed to a function, which is a backwards incompatible =
change.

But that is not the whole truth because it suggests that there was a =
warning in 7.4 which is not the case for functions like round() and =
possibly many more.

This makes the BC break much more impactful as there is no easy way to =
know if old code will suddenly abort with an exception whereas it used =
to run without any warning.

Is there any way of knowing what functions are affected by this?

This might be a blocker for people to migrate to PHP 8, should there be =
a way to have a warning-instead-of-exception stage added to PHP 8 even =
though there first versions were already released to help people =
migrate?

Or did I miss something?

- Chris


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