remote build: platform definitions cannot be parsed by Launchpad

[mr-cal]

Bug Description

Problem 1

Launchpad fails to parse many platforms definitions.

We need to complete canonical/craft-platforms#5 and sync with the Launchpad team to consume that build planner.

Problem 2

The legacy remote builder would only allow snaps that could build a single artefact on a build-on architecture. That is an architecture could only appear once in all build-on entries.

The new remote builder doesn't restrict this. This is a problem because Launchpad's API appears not to distinguish between build-on and build-for, so it is not clear Snapcraft can request builds.

To Reproduce

snapcraft remote-build --platform amd64

Environment

n/a

snapcraft.yaml

name: remote-build-platforms-error
version: "1.0"
summary: test
description: test
confinement: strict

base: core24

platforms:
  amd64:
    build-on: amd64
  arm64:
    build-on: amd64

parts:
  my-part:
    plugin: nil

Relevant log output

Multiple builds match the current platform.
Recommended resolution: Check the "--platform" and "--build-for" parameters.

Additional context

No response

[syncronize-issues-to-jira]

Thank you for reporting us your feedback!

The internal ticket has been created: https://warthogs.atlassian.net/browse/CRAFT-3069.

This message was autogenerated

[mr-cal]

upstream bug: https://bugs.launchpad.net/launchpad/+bug/2072622

[mr-cal]

This is mostly fixed by the upstream bug but #4994 solves scenarios with the --platform argument.