Re: Nullable types and strict type-hinting with default null value

Hi, On Wed, Feb 22, 2017 at 11:18 PM, Michał <aaatoja@o2.pl> wrote: > Hello PHP internals, > Scalar types declarations were introduced in PHP 7.0 but it was not > possible to pass null as a default value to function/method. It was finally > done by a small workaround described in documentation as "The declaration > can be made to accept NULL values if the default value of the parameter is > set to NULL". > > In PHP 7.1 and it's new feature - nullable types - this hack is, in my > opinion, completely unnecessary. It breaks valid type-hinting, is not > logical for advanced programmers, and may cause potential bugs. According > to docs "Type declarations allow functions to require that parameters are > of a certain type at call time. If the given value is of the incorrect > type, then an error is generated: in PHP 5, this will be a recoverable > fatal error, while PHP 7 will throw a TypeError exception.". Following > this, first line of code should throw error - but it does not, because of > 7.0 work-around. > > a(string $test=null) // incorrect type, should throw error > a(string $test='test') // valid type, ok > a(?string $test=null) // valid type, ok > a(?string $test='test') // valid type, ok > > There is no reason, except of backwards compatibility, to keep this > behaviour. It's too late to change this in 7.1, maybe even in 7.2. But, > what is Your opinion? Should it be preserved or fixed? > This isn't just a PHP 7 work-around for null types, it has existed since object type hints were introduced and is very widespread. Cheers, Andrey.