…anagi)

This PR was merged into the 3.3-dev branch.

Discussion
----------

[DI] Allow to count on lazy collection arguments

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #21450 (comment)
| License       | MIT
| Doc PR        | todo (with symfony/symfony-docs#7336)

When using the new iterator feature of the DI component to lazy load collection, we always know the number of arguments in the collection (only the invalidBehavior set to `IGNORE_ON_INVALID_REFERENCE` may change this number). So we are able to generate and use a `RewindableGenerator` implementing `\Countable` by computing this value ahead.

So, in a service accepting `array|iterable`, like in the `GuardAuthenticationListener` (see #21450):

```php
class GuardAuthenticationListener implements ListenerInterface
{
    private $guardAuthenticators;

    /**
       * @param iterable|GuardAuthenticatorInterface[]  $guardAuthenticators   The authenticators, with keys that match what's passed to GuardAuthenticationProvider
       * @param LoggerInterface                         $logger                A LoggerInterface instance
    */
    public function __construct($guardAuthenticators, LoggerInterface $logger = null)
    {
          // ...
    }

    public function handle(GetResponseEvent $event)
    {
        if (null !== $this->logger) {
            $context = array()
            if (is_array($this->guardAuthenticators) || $this->guardAuthenticators instanceof \Countable) {
                $context['authenticators'] = count($this->guardAuthenticators);
            }
            $this->logger->debug('Checking for guard authentication credentials.', $context);
        }
        // ...
    }
}
```

we still keep the ability to call count without loosing the lazy load benefits.

Commits
-------

f23e460 [DI] Allow to count on lazy collection arguments

…anagi)

This PR was merged into the 3.3-dev branch.

Discussion
----------

[DI] Allow to count on lazy collection arguments

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | symfony/symfony#21450 (comment)
| License       | MIT
| Doc PR        | todo (with symfony/symfony-docs#7336)

When using the new iterator feature of the DI component to lazy load collection, we always know the number of arguments in the collection (only the invalidBehavior set to `IGNORE_ON_INVALID_REFERENCE` may change this number). So we are able to generate and use a `RewindableGenerator` implementing `\Countable` by computing this value ahead.

So, in a service accepting `array|iterable`, like in the `GuardAuthenticationListener` (see #21450):

```php
class GuardAuthenticationListener implements ListenerInterface
{
    private $guardAuthenticators;

    /**
       * @param iterable|GuardAuthenticatorInterface[]  $guardAuthenticators   The authenticators, with keys that match what's passed to GuardAuthenticationProvider
       * @param LoggerInterface                         $logger                A LoggerInterface instance
    */
    public function __construct($guardAuthenticators, LoggerInterface $logger = null)
    {
          // ...
    }

    public function handle(GetResponseEvent $event)
    {
        if (null !== $this->logger) {
            $context = array()
            if (is_array($this->guardAuthenticators) || $this->guardAuthenticators instanceof \Countable) {
                $context['authenticators'] = count($this->guardAuthenticators);
            }
            $this->logger->debug('Checking for guard authentication credentials.', $context);
        }
        // ...
    }
}
```

we still keep the ability to call count without loosing the lazy load benefits.

Commits
-------

f23e460 [DI] Allow to count on lazy collection arguments

…cation providers (chalasr)

This PR was squashed before being merged into the 3.3-dev branch (closes #21450).

Discussion
----------

[Security] Lazy load guard authenticators and authentication providers

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | no
| New feature?  | yes
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

Authentication stops on the first authenticator that fails or succeeds, let's instantiate them only if actually needed.

Commits
-------

cd6422a [SecurityBundle] Lazy load authentication providers
b8a23de [Security][Guard] Lazy load authenticators