(Jubilee 2021.0.0-M1 + 2.6.0-M1) to (Jubilee 2021.0.0-M1 + 2.6.0-M2) The dependencies of some of the beans in the application context form a cycle: org.springframework.cloud.config.server.environment.vault.SpringVaultClientConfiguration

[patpatpat123]

A small issue observed after migration.

Disclaimer: I am filing this issue on Spring Cloud Config Server, but if you believe this issue should be for Spring Cloud, or Spring Boot, please let me know, I will close and amend.

Background:
I had a very simple Spring Cloud Config Server application: with version Jubilee 2021.0.0-M1 + 2.6.0-M1. Working fine, very happy.

@EnableConfigServer
@SpringBootApplication
public class Application {
    
    public static void main(String[] args) {
        SpringApplication.run(Application.class);
    }

}

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.0-M1</version>
        <relativePath/>
    </parent>
    
    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>2021.0.0-M1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

The M2 got announced here: https://spring.io/blog/2021/08/19/spring-boot-2-6-0-m2-is-now-available
Therefore, I went to do the version bump up to Jubilee 2021.0.0-M1 + 2.6.0-M2 a bit excited!

Unfortunately, after the version bump, application cannot startup, with this error

***************************
APPLICATION FAILED TO START
***************************

Description:

The dependencies of some of the beans in the application context form a cycle:

   pathMappedEndpoints defined in class path resource [org/springframework/boot/actuate/autoconfigure/endpoint/web/WebEndpointAutoConfiguration.class]
      ↓
   healthEndpoint defined in class path resource [org/springframework/boot/actuate/autoconfigure/health/HealthEndpointConfiguration.class]
      ↓
   healthContributorRegistry defined in class path resource [org/springframework/boot/actuate/autoconfigure/health/HealthEndpointConfiguration.class]
      ↓
   configServerHealthIndicator defined in class path resource [org/springframework/cloud/config/server/config/EnvironmentRepositoryConfiguration$ConfigServerActuatorConfiguration.class]
      ↓
   org.springframework.cloud.config.server.config.CompositeConfiguration
      ↓
   vaultEnvironmentRepository defined in class path resource [org/springframework/cloud/config/server/config/SpringVaultRepositoryConfiguration.class]
      ↓
   vaultEnvironmentRepositoryFactory defined in class path resource [org/springframework/cloud/config/server/config/EnvironmentRepositoryConfiguration$SpringVaultFactoryConfig.class]
┌─────┐
|  org.springframework.cloud.config.server.environment.vault.SpringVaultClientConfiguration
└─────┘


Action:

Relying upon circular references is discouraged and they are prohibited by default. Update your application to remove the dependency cycle between beans. As a last resort, it may be possible to break the cycle automatically be setting spring.main.allow-circular-references to true if you have not already done so.

Fore sure, it is the version bump, as I just change one number in the whole project (revert back to 2.6.0-M1 = work 2.6.0-M2 = does not work)

May I ask what is the issue? Maybe some workaround?

Hope this issue is helpful, thank you for your time.

[ryanjbaxter]

Can you try 2021.0.0-SNAPSHOT?

[patpatpat123]

Hello,

What kind of magic is that!
Indeed, issue resolved.
Thanks @ryanjbaxter

[patpatpat123]

(If I may ask, what is the root cause, and can the fix of this issue be expected for 2.6.0-M3 please?)

[ryanjbaxter]

There was a change in Spring Boot
spring-projects/spring-boot#27652

Our next Spring Cloud 2021.0.0 milestone will be compatible.

You can try using Spring Cloud 2021.0.0-M1 and set spring.main.allow-circular-references=true and see if that makes things work temporarily.

[patpatpat123]

Hello @ryanjbaxter,

As announce today https://spring.io/blog/category/releases "Spring Boot 2.6.0-M3 available now"

This is super exciting, thank you Spring Team.

Unfortunately, even after bumping to

<parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.6.0-M3</version>
        <relativePath/>
    </parent>

PLUS

<dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.cloud</groupId>
                <artifactId>spring-cloud-dependencies</artifactId>
                <version>2021.0.0-M1</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>

The problem still persists.

May I ask what is the correct way please? I was hoping this M3 release would fix the issue.

Thank you for your time

[ryanjbaxter]

The next Spring Cloud Milestone will address this, until that is released you will need to continue to use the property above.

The milestone should be released this week.

[patpatpat123]

Hello @ryanjbaxter,

Thank you for your input.
Confirmed, I just updated and the issue is resolved.
Thank you!