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<?php class A implements JsonSerializable { public function jsonSerialize() { return 'A'; } } $b = []; $b[] = new A(); $b[] = new A(); var_dump(json_encode($b));
Output for 8.1.0 - 8.1.34, 8.2.0 - 8.2.30, 8.3.0 - 8.3.4, 8.3.6 - 8.3.30, 8.4.1 - 8.4.18, 8.5.0 - 8.5.3
Deprecated: Return type of A::jsonSerialize() should either be compatible with JsonSerializable::jsonSerialize(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /in/n0PPI on line 4 string(9) "["A","A"]"
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 Deprecated: Return type of A::jsonSerialize() should either be compatible with JsonSerializable::jsonSerialize(): mixed, or the #[\ReturnTypeWillChange] attribute should be used to temporarily suppress the notice in /in/n0PPI on line 4 string(9) "["A","A"]"
Output for 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30
string(9) "["A","A"]"

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