AssumeRoleCredentialProvider replaces non-RuntimeException failures with TypeError #3370

Describe the bug

When an STS request throws an exception that doesn’t extend RuntimeException, AssumeRoleCredentialProvider replaces it with a TypeError and loses the original exception.

Regression Issue

• Select this option if this issue appears to be a regression.

Expected Behavior

I think other exceptions should pass through unchanged instead of being replaced with a type error.

Current Behavior

The example below fails with:

Argument #1 ($exception) must be of type RuntimeException, Exception given

The original exception is also lost: getPrevious() returns null.

Reproduction Steps

This example reproduces it without making any network requests or needing an AWS account.

Install aws/aws-sdk-php version 3.399.2, then run:

<?php

require 'vendor/autoload.php';

$client = new Aws\Sts\StsClient([
    'region' => 'us-east-1',
    'version' => '2011-06-15',
    'credentials' => ['key' => 'test', 'secret' => 'test'],
    'http_handler' => function () {
        throw new Exception('Request cancelled');
    },
]);

$provider = new Aws\Credentials\AssumeRoleCredentialProvider([
    'client' => $client,
    'assume_role_params' => [
        'RoleArn' => 'arn:aws:iam::123456789012:role/test',
        'RoleSessionName' => 'test',
    ],
]);

$provider()->wait();

Possible Solution

The rejection callback in AssumeRoleCredentialProvider::__invoke() only accepts RuntimeException. It could accept Throwable, keep the existing handling for RuntimeException, and rethrow other failures unchanged.

Additional Information/Context

The same callback is still present on master.

SDK version used

3.399.2

Environment details (Version of PHP (php -v)? OS name and version, etc.)

PHP 8.4.25, Ubuntu 24.04.

Generated by Codex, and reviewed by @binaryfire.