FYI Singletons are not behaving like singletons if you resolve them from container with parameters

[macropay-solutions]

https://laravel.com/docs/12.x/container#binding-a-singleton

This is a good behavior that is not documented:

        $concrete = $this->getContextualConcrete($abstract);

        $needsContextualBuild = ! empty($parameters) || ! is_null($concrete);

        // If an instance of the type is currently being managed as a singleton we'll
        // just return an existing instance instead of instantiating new instances
        // so the developer can keep using the same objects instance every time.
        if (isset($this->instances[$abstract]) && ! $needsContextualBuild) {
            return $this->instances[$abstract];
        }

        // If the requested type is registered as a singleton we'll want to cache off
        // the instances in "memory" so we can return it later without creating an
        // entirely new instance of an object on each subsequent request for it.
        if ($this->isShared($abstract) && ! $needsContextualBuild) {
            $this->instances[$abstract] = $object;
        }

[victormoni]

Hi @macropay-solutions

In Laravel, when you bind a class as a singleton, the container should always return the same instance.
However, if you resolve it with parameters, Laravel may treat it as a new contextual build meaning you won't get the same instance.

• The container checks if the abstract type is already instantiated and not in a contextual build.
• If parameters are passed (contextual build), it skips returning the cached singleton and creates a new instance.

if (isset($this->instances[$abstract]) && ! $needsContextualBuild) {
    return $this->instances[$abstract];
}

So, passing parameters sets $needsContextualBuild = true, bypassing the cached instance.

• If you want singleton behavior, avoid passing parameters when resolving from the container.
• If you must pass parameters, you will get a fresh instance.

References:

• Laravel Container - Binding a Singleton
• Laravel Container Source Code

[macropay-solutions]

@victormoni Thank you for this other way of saying what we said.
The heads up is for the lack of documentation for this GOOD feature.

[DanielCHood]

It makes sense that the container generates a new instance based on parameters but I would like to see it return the same instance if you generate with the same parameters again. So, basically, unique singletons based on parameters

[AhmedAlaa4611]

I try to document it here: laravel/docs#10741

[AhmedAlaa4611]

Taylor Otwell said:

This should probably be given along with an example.

What would be a clear example to illustrate this in the docs?

[macropay-solutions]

\app(Class::class); // or resolve
// vs
\app(Class::class, [
    'param1' => 1,
    'param2' => 2,
]);