Parse Docker images of `<name>:<tag>@sha256:<hash>` format

[remal]

Currently, DockerImageName doesn't support image names in <name>:<tag>@sha256:<hash> format, as it expects image name to be in one of these formats:

• <name>:<tag>
• <name>@sha256:<hash>

However, <name>:<tag>@sha256:<hash> is a valid Docker image name format. Could you please add its support?

As a result, I expect DockerImageName to ignore tags of such image names and work with hash only. Tags can be returned via toString().

[bedla]

It is already support, this might be closed.

Code

import java.lang.reflect.Field;

class Scratch {
    public static void main(String[] args) throws IllegalAccessException {
        dumpInfo("alpine");
        dumpInfo("alpine:3.23.2");
        dumpInfo("alpine:3.23.2@sha256:865b95f46d98cf867a156fe4a135ad3fe50d2056aa3f25ed31662dff6da4eb62");
        dumpInfo("alpine@sha256:865b95f46d98cf867a156fe4a135ad3fe50d2056aa3f25ed31662dff6da4eb62");
    }

    static void dumpInfo(String imageStr) throws IllegalAccessException {
        DockerImageName image = DockerImageName.parse(imageStr);
        System.out.println("-> " + image);
        System.out.println("Registry = " + image.getRegistry());
        System.out.println("Repository = " + image.getRepository());

        System.out.print("VersionPart = " + image.getVersionPart());
        String versioningClass = versioningField.get(image).getClass().getSimpleName();
        System.out.println("\t(" + versioningClass + ")");

        System.out.println("UnversionedPart = " + image.getUnversionedPart());
        System.out.println();
    }

    private static final Field versioningField;

    static {
        try {
            versioningField = DockerImageName.class.getDeclaredField("versioning");
            versioningField.setAccessible(true);
        } catch (NoSuchFieldException e) {
            throw new RuntimeException(e);
        }
    }
}

Output

-> alpine:latest
Registry = 
Repository = alpine
VersionPart = latest	(AnyVersion)
UnversionedPart = alpine

-> alpine:3.23.2
Registry = 
Repository = alpine
VersionPart = 3.23.2	(TagVersioning)
UnversionedPart = alpine

-> alpine:3.23.2@sha256:865b95f46d98cf867a156fe4a135ad3fe50d2056aa3f25ed31662dff6da4eb62
Registry = 
Repository = alpine:3.23.2     <<<<================ this seems incorrect with TC v2.0.3 ... see comments below

VersionPart = sha256:865b95f46d98cf867a156fe4a135ad3fe50d2056aa3f25ed31662dff6da4eb62	(Sha256Versioning)
UnversionedPart = alpine:3.23.2

-> alpine@sha256:865b95f46d98cf867a156fe4a135ad3fe50d2056aa3f25ed31662dff6da4eb62
Registry = 
Repository = alpine
VersionPart = sha256:865b95f46d98cf867a156fe4a135ad3fe50d2056aa3f25ed31662dff6da4eb62	(Sha256Versioning)
UnversionedPart = alpine

[remal]

I wouldn't say putting tag into Repository and UnversionedPert is an expected behavior. If I were to use it, I'd have a lot of doubts about correctness of this.

[bedla]

Hmm, I missed this detail. You are IMO correct.

Based on this grammar https://github.com/distribution/reference/blob/v0.6.0/reference.go#L1-L26 ,
I have prepared this PR #11368 .