minor #38220 [Security] Log notice when no entry point is configured (wouterj)

This PR was merged into the 5.1 branch.

Discussion
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[Security] Log notice when no entry point is configured

| Q             | A
| ------------- | ---
| Branch?       | 5.1
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix #37068
| License       | MIT
| Doc PR        | -

In the new security system, authenticators are not necessarily authentication entry points. This can cause unexpected behavior if no entry point is configured. It's not really an error, that's why I choose the "notice" level: "Normal but significant events".

Commits
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68f891ff65 Log notice when no entry point is configured

src/Symfony/Bundle/SecurityBundle/DependencyInjection/MainConfiguration.php

@@ -16,6 +16,7 @@ use Symfony\Component\Config\Definition\Builder\ArrayNodeDefinition;
 use Symfony\Component\Config\Definition\Builder\TreeBuilder;
 use Symfony\Component\Config\Definition\ConfigurationInterface;
 use Symfony\Component\Security\Core\Authorization\AccessDecisionManager;
+use Symfony\Component\Security\Http\EntryPoint\AuthenticationEntryPointInterface;
 use Symfony\Component\Security\Http\Event\LogoutEvent;
 use Symfony\Component\Security\Http\Session\SessionAuthenticationStrategy;
 
@@ -194,7 +195,9 @@ class MainConfiguration implements ConfigurationInterface
             ->scalarNode('request_matcher')->end()
             ->scalarNode('access_denied_url')->end()
             ->scalarNode('access_denied_handler')->end()
-            ->scalarNode('entry_point')->end()
+            ->scalarNode('entry_point')
+                ->info(sprintf('An enabled authenticator name or a service id that implements "%s"', AuthenticationEntryPointInterface::class))
+            ->end()
             ->scalarNode('provider')->end()
             ->booleanNode('stateless')->defaultFalse()->end()
             ->booleanNode('lazy')->defaultFalse()->end()

src/Symfony/Component/Security/Http/Firewall/ExceptionListener.php

@@ -195,6 +195,10 @@ class ExceptionListener
     private function startAuthentication(Request $request, AuthenticationException $authException): Response
     {
         if (null === $this->authenticationEntryPoint) {
+            if (null !== $this->logger) {
+                $this->logger->notice(sprintf('No Authentication entry point configured, returning a %s HTTP response. Configure "entry_point" on the firewall ("{firewall_name}") if you want to modify the response.', Response::HTTP_UNAUTHORIZED), ['firewall_name' => $this->providerKey]);
+            }
+
             throw new HttpException(Response::HTTP_UNAUTHORIZED, $authException->getMessage(), $authException, [], $authException->getCode());
         }