What is the problem you're trying to solve

BuildKit added the --build-context argument to enable users to provide additional build contexts during a build. More documentation about this can be found here.

Describe the solution you'd like

Being able to configure additional build contexts in a Compose file, such as:

services:
  a:
    build:
      context: .
      build_contexts:
        - project=[a directory/image/etc.]

Used together with a Dockerfile such as:

# syntax=docker/dockerfile:1
FROM alpine:latest
COPY --from=project . /

Additional context
Add any other context about the feature request here.

• Add support for additional build contexts docker/compose#9961 => Dev Containers 0.255.2 docker compose problem microsoft/vscode-remote-release#7305