Broken build while using older version of docker

[skylax1]

Do you want to request a feature or report a bug?

bug

What is the current behavior?

I have an old repo that uses Circle CI + heroku cli to build and deploy my django website. Since release 9.0.0 my build is failing. Command that fails:

heroku container:push web -a $HEROKU_APP_NAME

Error:

"--platform" is only supported on a Docker daemon with experimental features enabled
 ›   Error: docker build exited with Error: 1

Apparently this happens because someone thought it was a good idea to pin build platform to linux/amd64(why this specific platform?) here

cli/packages/cli/src/lib/container/docker_helper.ts

Line 168 in e1e5252

const args = ['build', '-f', dockerfile, '-t', resource, '--platform', 'linux/amd64']

My Circle CI flow uses very old docker image with python3.6 and node 10. Docker version is 18.09.7.

I know this thing is ancient, but was it necessary to add that "--platform" flag in 9.0.0?

What is the expected behavior?

heroku container:push should not fail with error. When I use older version of heroku cli (8.1.4) my build is not failing.

[k80bowman]

Internal work item

Thank you for letting us know. We will take a look.