Documentation regarding warning on unused build args is no longer accurate with BuildKit

[Ga22be]

Is this a docs issue?

• [X] My issue is about the documentation content or website

Type of issue

Information is incorrect

Description

The documentation for Dockerfiles and ARGs state:

If you specify a build argument that wasn't defined in the Dockerfile, the build outputs a warning.

"[Warning] One or more build-args [foo] were not consumed."

This didn't work for me and I was pulling my hair until I found this: https://github.com/moby/buildkit/issues/2128

It does however work if I disable BuildKit using: DOCKER_BUILDKIT=0

Location

https://docs.docker.com/reference/dockerfile/

Suggestion

While the simple solution would be to remove the information all together I would like it to temporarily note that it works for the old builder. The error was useful and if it is removed now I fear that it will not be added again if fixed in BuildKit.