Bug #72119 [Com]: Interface declaration compatibility regression with default values

Edit report at https://bugs.php.net/bug.php?id=72119&edit=1

 ID:                 72119
 Comment by:         rowan dot collins at gmail dot com
 Reported by:        ben dot davies at gmail dot com
 Summary:            Interface declaration compatibility regression with
                     default values
 Status:             Not a bug
 Type:               Bug
 Package:            PHP Language Specification
 PHP Version:        7.0.6
 Assigned To:        levim
 Block user comment: N
 Private report:     N

 New Comment:

Given that it has the potential to break existing code, I think it would make more sense to fix it in 7.1, when people will be expecting to check changelogs and update code. Breaking compatibility in a patch release will just lead to people not trusting the official releases, and thus not getting important security fixes, which is in nobody's interest.


Previous Comments:
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[2016-04-28 16:42:51] [email protected]

Correct; it should never have worked in the first place though;
While it technically is a BC break, I personally think this was in the first place an important (long-term) bugfix. [which thus shouldn't be reverted in 7.0.7]

------------------------------------------------------------------------
[2016-04-28 16:34:14] [email protected]

The original problem was introduced by attempt to fix #71428 (that expects exactly the opposite behavior) in commit ee9a78a033696ff9546fb1dbfecd28f20477b511

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[2016-04-28 15:26:30] ben dot davies at gmail dot com

Hi both,

No doubt you are both correct, but this appears to be a BC break.
This works in every version of php up to 7.0.6.

https://3v4l.org/VhEtd

Thanks

------------------------------------------------------------------------
[2016-04-28 15:23:48] [email protected]

I have confirmed that this is not a bug. The reason is that in the interface you are permitted to pass null:

<?php
$Foo->bar(null);
?>

However, in the implementing class Hello it would not be permitted. Everything permitted in the parent must also be permitted in the child, thus it is not a bug.

------------------------------------------------------------------------
[2016-04-28 15:22:29] [email protected]

This is not a bug; your code is a LSP violation which had been fixed in bug #71428.

In the concrete example, the Foo::bar() function can be passed null, but Hello::bar() cannot.

[This is something we try to fix with nullable parameters/null unions in 7.1.]

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