oop – Page 8 – Türker Yıldırım

__destruct runs at an unpredictable moment, and may not run

NoteDecember 10, 20222 min read

A destructor runs when the last reference is dropped, which is not the same as when the variable goes out of scope, and not at all on a…

A readonly class is readonly on every property

NoteDecember 8, 20222 min read

Writing readonly on every property of a value object was the only way to say something the class as a whole was trying to say. The class modifier…

A readonly class may only be extended by a readonly class

NoteDecember 8, 20222 min read

Inheritance is constrained in one direction only, which means a readonly base cannot be subverted and a mutable base can still be tightened. The symmetry is the surprise:…

null, false and true as standalone types

NoteDecember 7, 20222 min read

false had been usable only as part of a union since 8.0, and null and true could not be written at all. Narrowing a return type in a…

#[AllowDynamicProperties], and when it is honest

NoteDecember 5, 20222 min read

The attribute opts a class out of the deprecation, which is occasionally correct and is usually a way of deferring a rename. Inheritance of the attribute is the…

Serialising an enum, and the case that was renamed

NoteNovember 15, 20222 min read

serialize on a pure enum stores the case name, and on a backed enum stores the value, which makes the two behave differently across a rename. Native serialisation…

Enum constants are implicitly final

NoteOctober 6, 20222 min read

An enum cannot be extended, so every constant on it is final by construction and the keyword is redundant rather than forbidden. A constant whose value is a…

An enum case cannot carry state, and that is deliberate

NoteSeptember 30, 20222 min read

A case is a singleton, so a mutable property on it would be shared by every reference in the process, and the language forbids properties outright rather than…

A backed enum’s value is a contract once it reaches a queue

NoteJune 21, 20222 min read

An enum serialised into a queued job payload is a value that must still be resolvable when the job runs, which may be after the next deploy. This…

static::class inside a trait resolves to the using class

NoteJune 9, 20222 min read

A trait is copied into the using class at compile time, so self, static and __CLASS__ all refer to the class rather than to the trait. This is…