Document how "COPY --link" is suported (docker/dockerfile:1.4)

[finkr]

Hello,

Could you document whether COPY --link (from docker/dockerfile:1.4) is supported and/or it's roadmap.

With --link the layer the previous build generated is reused and merged on top of the new layers. This also means you can easily rebase your images when the base images receive updates, without having to execute the whole build again.

Thanks

Franklin

[guillaume-d]

It is not (not even syntactically), see https://github.com/GoogleContainerTools/kaniko/issues/1568#issuecomment-1113512645 (search for 1.4 there).