Allow preparation of providers to be optional

src/bundle/DependencyInjection/Factory/Security/TwoFactorFactory.php

@@ -169,6 +169,6 @@ public function getKey(): string
 
     public function getPriority(): int
     {
-        return 0;
+        return -50;
     }
 }

src/bundle/Security/TwoFactor/Provider/TwoFactorProviderInitiator.php

@@ -48,6 +48,18 @@ public function beginTwoFactorAuthentication(AuthenticationContextInterface $con
         if ($activeTwoFactorProviders) {
             $twoFactorToken = $this->twoFactorTokenFactory->create($authenticatedToken, $context->getFirewallName(), $activeTwoFactorProviders);
 
+            // Mark all providers which do *not* need to be prepared, to `prepared` so the preparation process is skipped.
+            // This way these providers can be used to verify the second factor immediately
+            foreach ($activeTwoFactorProviders as $providerName) {
+                $provider = $this->providerRegistry->getProvider($providerName);
+
+                if ($provider->needsPreparation()) {
+                    continue;
+                }
+
+                $twoFactorToken->setTwoFactorProviderPrepared($providerName);
+            }
+
             $preferredProvider = $this->twoFactorProviderDecider->getPreferredTwoFactorProvider($activeTwoFactorProviders, $twoFactorToken, $context);
 
             if (null !== $preferredProvider) {

src/bundle/Security/TwoFactor/Provider/TwoFactorProviderInterface.php

@@ -13,6 +13,11 @@ interface TwoFactorProviderInterface
      */
     public function beginAuthentication(AuthenticationContextInterface $context): bool;
 
+    /**
+     * Determine whether this Provider needs to be prepared (if the prepareAuthentication method needs to be called).
+     */
+    public function needsPreparation(): bool;
+
     /**
      * Do all steps necessary to prepare authentication, e.g. generate & send a code.
      */

src/email/Security/TwoFactor/Provider/Email/EmailTwoFactorProvider.php

@@ -30,6 +30,11 @@ public function beginAuthentication(AuthenticationContextInterface $context): bo
         return $user instanceof TwoFactorInterface && $user->isEmailAuthEnabled();
     }
 
+    public function needsPreparation(): bool
+    {
+        return true;
+    }
+
     public function prepareAuthentication(object $user): void
     {
         if (!($user instanceof TwoFactorInterface)) {

src/google-authenticator/Security/TwoFactor/Provider/Google/GoogleAuthenticatorTwoFactorProvider.php

@@ -38,6 +38,11 @@ public function beginAuthentication(AuthenticationContextInterface $context): bo
         return true;
     }
 
+    public function needsPreparation(): bool
+    {
+        return false;
+    }
+
     public function prepareAuthentication(object $user): void
     {
     }

src/totp/Security/TwoFactor/Provider/Totp/TotpAuthenticatorTwoFactorProvider.php

@@ -42,6 +42,11 @@ public function beginAuthentication(AuthenticationContextInterface $context): bo
         return true;
     }
 
+    public function needsPreparation(): bool
+    {
+        return false;
+    }
+
     public function prepareAuthentication(object $user): void
     {
     }