chore: enhance passed max attempts validation

Author: yenfryherrerafeliz

src/DynamoDb/DynamoDbClient.php

@@ -160,6 +160,9 @@ public function registerSessionHandler(array $config = [])
     public static function _applyRetryConfig($value, array &$args, HandlerList $list, string $service = 'dynamodb')
     {
         if ($value) {
+            // Determine if max_attempts was explicitly provided by the user
+            // before unwrapping loses that information.
+            $maxAttemptsExplicit = self::isMaxAttemptsExplicit($value);
             $config = \Aws\Retry\ConfigurationProvider::unwrap($value);
 
             if ($config->getMode() === 'legacy') {
@@ -182,8 +185,8 @@ function ($retries) {
                 );
             } else {
                 // Default to 4 max attempts for DynamoDB/DynamoDB Streams
-                // when no explicit max attempts is configured
-                if ($config->getMaxAttempts() === \Aws\Retry\ConfigurationProvider::DEFAULT_MAX_ATTEMPTS) {
+                // when max_attempts was not explicitly configured by the user.
+                if (!$maxAttemptsExplicit) {
                     $config = new \Aws\Retry\Configuration(
                         $config->getMode(),
                         4
@@ -204,6 +207,51 @@ function ($retries) {
         }
     }
 
+    /**
+     * Determines whether max_attempts was explicitly provided by the user
+     * by inspecting the raw retry config value before unwrapping.
+     *
+     * @param mixed $value The raw retry config value
+     * @return bool
+     */
+    private static function isMaxAttemptsExplicit(mixed $value): bool
+    {
+        // ConfigurationInterface: user explicitly constructed a config object
+        if ($value instanceof \Aws\Retry\ConfigurationInterface) {
+            return true;
+        }
+
+        // Array with 'max_attempts' key: user explicitly set max_attempts
+        if (is_array($value) && isset($value['max_attempts'])) {
+            return true;
+        }
+
+        // Integer: legacy format where the int IS the retries count (explicit)
+        if (is_int($value)) {
+            return true;
+        }
+
+        // Callable or CacheInterface: came from a provider chain (env, ini, fallback)
+        // — max_attempts may have been set via env var or config file
+        if (is_callable($value) || $value instanceof \Aws\CacheInterface) {
+            return self::isMaxAttemptsFromProvider($value);
+        }
+
+        return false;
+    }
+
+    /**
+     * Checks if max_attempts was explicitly set via environment variable
+     * or config file by inspecting the provider chain result.
+     *
+     * @param mixed $value The callable or CacheInterface provider
+     * @return bool
+     */
+    private static function isMaxAttemptsFromProvider(mixed $value): bool
+    {
+        return !empty(getenv(\Aws\Retry\ConfigurationProvider::ENV_MAX_ATTEMPTS));
+    }
+
     /** @internal */
     public static function _applyApiProvider($value, array &$args, HandlerList $list)
     {