servlet.multipart.enabled is disabled by default in 4.2.1

[Lemick]

Describe the bug Starting from Spring Cloud Gateway 4.2.1, the default behavior for handling multipart requests has changed. If servlet.multipart.enabled: true is not explicitly set, this setting is disabled by MultipartEnvironmentPostProcessor and body parameters from multipart/form-data requests are not accessible.

This differs from previous behavior and from Spring Boot’s default, making it an unexpected change for users upgrading. Maybe a reference in the release notes or in the documentation could be useful ?

Sample A minimal Spring Boot application using spring-cloud-starter-gateway-mvc:4.2.1 with a POST request containing multipart/form-data parameters does not receive expected body parameters unless the following is explicitly added:

spring:
  servlet:
    multipart:
      enabled: true