Add annotation for descriptor

[tosone]

distribution.Descriptor defined a field annotation, but distribution.UnmarshalManifest output descriptor cannot get the annotation.
We should fill the field correctly.

[Jamstah]

Thanks for the pr. Can you please describe the motivation and purpose for this change?

[tosone]

@Jamstah Please review again. ^_^

[Jamstah]

OK, great, I'm caught up :)

Can you please add a test for this?

[tosone]

Test case added.

[Jamstah]

I ran the tests without the code change and they passed - I don't think the new tests are actually testing that the change makes it back to the descriptor otherwise they would have failed.

[tosone]

After i remove the changes will get this error:

=== RUN   TestManifestUnmarshal
    manifest_test.go:159: manifest annotation not equal:
        expected:
        map[hot:potato]
        actual:
        map[]
--- FAIL: TestManifestUnmarshal (0.00s)

=== RUN   TestOCIManifestIndexUnmarshal
    index_test.go:146: manifest index annotation not equal:
        expected:
        map[com.example.favourite-colour:blue com.example.locale:en_GB]
        actual:
        map[]
--- FAIL: TestOCIManifestIndexUnmarshal (0.00s)

Also length check added:

if len(descriptor.Annotations) != 2 {
	t.Fatalf("manifest index annotation length should be 2")
}

[Jamstah]

Apologies, you're absolutely right. It turns out vscode was caching more aggressively than I expected.

Changes look great.

One (hopefully) last question: What does this fix from an external point of view? The changes all make sense, but is there something broken for users that this fixes?

[tosone]

Yes, my new project sigma, need to unmarshal the manifest, in some scenario, the annotation has some information, and some of the code snippet like here. https://github.com/go-sigma/sigma/blob/main/pkg/daemon/tagpushed/tagpushed.go#L96

[Jamstah]

OK, so you're using the project as a library to parse manifests?

Thanks :)

[tosone]

yes.

[milosgajdos]

Nice! Thanks!