introduce build --check

[ndeloof]

What I did

introduce build --check flag to let bake run with call=lint (aligned with docker build --check)

Related issue
fix #12749

(not mandatory) A picture of a cute animal, if possible in relation to what you did

[glours]

LGTM

[johnthagen]

@ndeloof We'd like for docker compose build --check to fail our CI if there are any warnings (so that regressions are caught before they are accepted into main). Is there a way to do that from the CLI?

From our testing, it seems to only print a warning and then continue on and complete the build successfully.

Environment

$ docker version
Client:
 Version:           28.2.2
 API version:       1.50
 Go version:        go1.24.3
 Git commit:        e6534b4
 Built:             Fri May 30 12:07:14 2025
 OS/Arch:           linux/amd64
 Context:           default
Server: Docker Engine - Community
 Engine:
  Version:          28.2.2
  API version:      1.50 (minimum version 1.24)
  Go version:       go1.24.3
  Git commit:       45873be
  Built:            Fri May 30 11:52:20 2025
  OS/Arch:          linux/amd64
  Experimental:     false
 containerd:
  Version:          v1.7.27
  GitCommit:        05044ec0a9a75232cad458027ca834[37](https://gitlab.jhuapl.edu/PCBDR/pcbdr/-/jobs/11988920/viewer#L37)aae3f4da
 runc:
  Version:          1.2.6
  GitCommit:        v1.2.6-0-ge89a299
 docker-init:
  Version:          0.19.0
  GitCommit:        de[40](https://gitlab.jhuapl.edu/PCBDR/pcbdr/-/jobs/11988920/viewer#L40)ad0
$ docker compose version
Docker Compose version v2.36.2

[ndeloof]

@johnthagen can't you achieve this with docker buildx bake which offers more options ?

[johnthagen]

@ndeloof Interesting suggestion. I hadn't used buildx bake much, so I wasn't as familiar.

I did try it out and docker buildx bake --check did what I expected (only checked the configuration, did not perform full builds, and returns an error status code on any warning).

I'd argue that is what I was hoping for when I opened #12749 and recommend that docker compose build --check do the same thing. I think otherwise people will be surprised when it doesn't act like docker build --check and docker buildx bake --check.

Further, I see value in Compose users not needing to learn buildx bake for something simple like linting their Dockerfiles. So I'd recommend that Compose --check work the same as buildx back --check.

[ndeloof]

I agree about your expectation and compose behavior that need to get fixed, just giving you a short terms workaround
Also, bake will soon-ish become the default builder used by docker compose, so better keep an eye on it :)

[johnthagen]

just giving you a short terms workaround

Thanks! We've already put this in our CI pipelines for now.

I agree about your expectation and compose behavior that need to get fixed

👍