82f0e1e5d8
This commit brings a more pedantic change in the following ambiguous case: cat Dockerfile | docker build -f otherDockerfile - The legacy builder does not error out and prefers the Dockerfile from stdin while the buildkit-based one errors out. Note that this is only in the case where stdin is a Dockerfile (not an archive) Signed-off-by: Tibor Vass <tibor@docker.com>