SpringBoot getSigners() info is lost for signed jars when using the new loader implementation with requiresUnpack

Bug report

After upgrading to Spring Boot 3.2, my application stops working, until I add the <loaderImplementation>CLASSIC</loaderImplementation> configuration to the repackage Maven goal.

The particularity of my application, is that one of the jars is a security library which is signed (the library recuperates the signature via Class::getSigners() to verify it when initializing). In previous versions of Spring Boot, requiresUnpack used to do the trick:

<plugin>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-maven-plugin</artifactId>
    <configuration>
        <requiresUnpack>
            <dependency>
                <groupId>eu.europa.ec.digit.iam.eulogin.client</groupId>
                <artifactId>eulogin-tomcat-10.0</artifactId>
            </dependency>
        </requiresUnpack>
    </configuration>
    ...
</plugin>

Now, the application only works by reverting to the CLASSIC loader implementation.

By debugging the application, I see the following differences between the two cases:

In the CLASSIC loader, the library is loaded via LaunchedURLClassLoader using the scheme file:/...

and the signers are correctly returned:

In the new loader, the library is loaded via LaunchedClassLoader using the scheme jar:file:/...

and the signers are lost:

It would be desirable that the getSigners() info of signed jars is preserved by the loader, when using the repackage Maven goal.

Comment From: philwebb

Thanks for the analysis @lburja. Hopefully fixed for the next release.