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Date: Mon, 3 Aug 2020 05:49:42 +0100
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Subject: Re: Feature Request: dependencies container
From: marandall@php.net (Mark Randall)
Message-ID: <php.internals-111293@news.php.net>

On 03/08/2020 04:31, 3u93n3 wrote:
> The main idea is to take control over objects creation and injecting 
> dependencies.
Hi 3u93n3,

Thank you for the effort. However, it is generally accepted that this 
kind of functionality belongs to userland rather than the core.

There are a few issues with this proposal:

1. It depends on global state (register_dependency_bindings) which is 
something we aim to avoid as in the vast majority of cases it leads to 
unfortunate outcomes and difficulty in maintaining code.

2. It introduces more language magic, and sentiment is generally against 
more magic.

Most of all though, this problem has already been solved in userland by 
instantiating objects via factories - no magic involved, just static code.

With (presumably) 8.0 and the introduction of attributes, existing 
dependency injection frameworks will have additional methods of cleanly 
expressing which constructor fields are injected, and which are user 
supplied.

We might even expect that these frameworks will be updated to take 
advantage of this and include automatically generated factories:

#[Service]
class Foo {
    public function __construct(
      #[Inject] Foo $foo,
      #[Inject] Bar $bar,
      string $value
    ) {
      ...
    }
}

$container->factories(Foo::class)("value");

Mark Randall