The return type of return new \SecurityLib\...yLib\Strength::MEDIUM); (SecurityLib\Strength) is incompatible with the return type declared by the interface RandomLib\Source::getStrength of type RandomLib\Strength.
If you return a value from a function or method, it should be a sub-type of the
type that is given by the parent type f.e. an interface, or abstract method.
This is more formally defined by the
Lizkov substitution principle,
and guarantees that classes that depend on the parent type can use any instance
of a child type interchangably. This principle also belongs to the
SOLID principles
for object oriented design.
Our function my_function expects a Post object, and outputs the author
of the post. The base class Post returns a simple string and outputting a
simple string will work just fine. However, the child class BlogPost which
is a sub-type of Post instead decided to return an object, and is
therefore violating the SOLID principles. If a BlogPost were passed to
my_function, PHP would not complain, but ultimately fail when executing the
strtoupper call in its body.
The return type of return new \SecurityLib\...ityLib\Strength::HIGH); (SecurityLib\Strength) is incompatible with the return type declared by the interface RandomLib\Source::getStrength of type RandomLib\Strength.
If you return a value from a function or method, it should be a sub-type of the
type that is given by the parent type f.e. an interface, or abstract method.
This is more formally defined by the
Lizkov substitution principle,
and guarantees that classes that depend on the parent type can use any instance
of a child type interchangably. This principle also belongs to the
SOLID principles
for object oriented design.
Our function my_function expects a Post object, and outputs the author
of the post. The base class Post returns a simple string and outputting a
simple string will work just fine. However, the child class BlogPost which
is a sub-type of Post instead decided to return an object, and is
therefore violating the SOLID principles. If a BlogPost were passed to
my_function, PHP would not complain, but ultimately fail when executing the
strtoupper call in its body.
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50
}
51
52
/**
53
* Generate a random string of the specified size
54
*
55
* @param int $size The size of the requested random string
56
*
57
* @return string A string of the requested size
58
*/
59
public function generate($size) {
60
if (!function_exists('openssl_random_pseudo_bytes') || $size < 1) {
61
return str_repeat(chr(0), $size);
62
}
63
/**
64
* Note, normally we would check the return of of $crypto_strong to
65
* ensure that we generated a good random string. However, since we're
66
* using this as one part of many sources a low strength random number
ircmaxell /
RandomLib
Anthony Ferrara
Alexander Obuhovich
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If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design.
Let’s take a look at an example:
Our function
my_functionexpects aPostobject, and outputs the author of the post. The base classPostreturns a simple string and outputting a simple string will work just fine. However, the child classBlogPostwhich is a sub-type ofPostinstead decided to return anobject, and is therefore violating the SOLID principles. If aBlogPostwere passed tomy_function, PHP would not complain, but ultimately fail when executing thestrtouppercall in its body.