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?
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