<?php
class A {protected $a = 'A'; /*public function __get($f){ return 'field_'.$f; }*/}
class B1 extends A {}
class B2 extends A {protected $a = 'B';}
class C extends A {
public function foo(A $a) {
echo $a->a; // will fail depends on $a implementation
// liskov substitution principle failed
}
}
$a = new A();
$b1 = new B1();
$b2 = new B2();
$c = new C();
$c->foo($b1); // ok
$c->foo($b2); // not ok?
A
Fatal error: Uncaught Error: Cannot access protected property B2::$a in /in/OibCN:8
Stack trace:
#0 /in/OibCN(17): C->foo(Object(B2))
#1 {main}
thrown in /in/OibCN on line 8
Process exited with code 255.
Output for 8.3.5
Warning: PHP Startup: Unable to load dynamic library 'sodium.so' (tried: /usr/lib/php/8.3.5/modules/sodium.so (libsodium.so.23: cannot open shared object file: No such file or directory), /usr/lib/php/8.3.5/modules/sodium.so.so (/usr/lib/php/8.3.5/modules/sodium.so.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
A
Fatal error: Uncaught Error: Cannot access protected property B2::$a in /in/OibCN:8
Stack trace:
#0 /in/OibCN(17): C->foo(Object(B2))
#1 {main}
thrown in /in/OibCN on line 8
Process exited with code 255.
A
Fatal error: Cannot access protected property B2::$a in /in/OibCN on line 8
Process exited with code 255.
Output for 5.0.0 - 5.0.5, 5.1.1 - 5.1.6
Fatal error: Cannot access protected property B1::$a in /in/OibCN on line 8
Process exited with code 255.
Output for 5.1.0
Fatal error: fatal flex scanner internal error--end of buffer missed in /in/OibCN on line 17
Process exited with code 255.
Output for 4.4.2 - 4.4.9
Parse error: syntax error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' in /in/OibCN on line 3
Process exited with code 255.
Parse error: parse error, unexpected T_STRING, expecting T_OLD_FUNCTION or T_FUNCTION or T_VAR or '}' in /in/OibCN on line 3
Process exited with code 255.
Output for 4.3.2 - 4.3.4
Parse error: parse error, expecting `T_OLD_FUNCTION' or `T_FUNCTION' or `T_VAR' or `'}'' in /in/OibCN on line 3
Process exited with code 255.