Dev tools causes misconfigured command-line application to exit with 0

[msmerc]

I have a really simple spring application that's misconfigured:

@SpringBootApplication()
public class SimpleApplication implements CommandLineRunner {
    public static void main(String[] args) {
        var ctx = SpringApplication.run(SimpleApplication.class, args);
        System.exit(SpringApplication.exit(ctx));
    }

    public static class MyObject {}
    
    //Oops - No bean provided!!!
    @Autowired MyObject myObject;

    @Override public void run(String... args) { }
}

I get the following error (in intellij):

...
Consider defining a bean of type 'test.app.SimpleApplication$MyObject' in your configuration.


Process finished with exit code 1

Which is what I'd expect.

If I add the spring-boot-devtools dependency in maven:

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

Then I get the following:

...
Consider defining a bean of type 'test.app.SimpleApplication$MyObject' in your configuration.


Process finished with exit code 0

It seems that adding this package causes spring boot to have the wrong return codes.

[msmerc]

Here's my full maven config:

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>springboot-test</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>13</maven.compiler.source>
        <maven.compiler.target>13</maven.compiler.target>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>2.5.5</version>
                <type>pom</type>
                <scope>import</scope>
            </dependency>
        </dependencies>
    </dependencyManagement>
    <dependencies>
        <!-- This dependency causes the issue -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>
    </dependencies>
</project>

[cdmatta]

1. The app runs within a RestartLauncher due to devtools
   https://github.com/spring-projects/spring-boot/blob/v2.5.6/spring-boot-project/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/restart/RestartLauncher.java#L46-L53

2. When SpringApplication handles the failure it invokes SpringBootExceptionHandler.registerLoggedException for UnsatisfiedDependencyException

3. The last thing SpringApplication does is ReflectionUtils.rethrowRuntimeException(exception);
   SpringApplication.java

4. This causes the exception seen in RestartLauncher to be java.lang.reflect.InvocationTargetException containing target UnsatisfiedDependencyException

5. Finally, SpringBootExceptionHandler has a registered Exception UnsatisfiedDependencyException .. does not have InvocationTargetException as a registed exception and thus the exit code is 0

Ideally, in this case it should investigate the target of the exception and match it

[wilkinsona]

#26894 is in a similar area.

[CangYa2021]

@cdmatta @wilkinsona
When relying on developmentOnly'org.springframework.boot:spring-boot-devtools', the SpringBoot project will schedule the org.springframework.boot.devtools.restart.RestartLauncher#run() function in devtools when it starts, and the abnormal status code 0 is returned by the abnormal status of devtools,
I guess this problem should be related to the operating principle of spring-boot-devtools.

[CangYa2021]

@msmerc @cdmatta
You can debug at the following methods.

@wilkinsona I think this situation is not a bug, isn't it ?

[msmerc]

If this is the intended behavior then I think spring-boot-devtools needs to inform the user that it's changed the exit code! Otherwise this is very non-obvious. Took me ages to track down the culprit.

[wilkinsona]

It looks like a bug to me. preventNonZeroExitCode() should only come into play if the JVM is exiting due to Dev Tools' own SilentExitException. For any other failure the intent is that the exit code should be unchanged. From what @cdmatta has described above, it's an UnsatisfiedDependencyException so the code that's specific to SilentExitException shouldn't be involved.