Compose silently ignored several spec-valid attributes it doesn't
honor outside Swarm mode: deploy.update_config, credential_spec,
ports[].mode: host, and others had no visible effect on a plain
`docker compose up`.
Detection is wired into compose-go's loader as a fail-closed
allowlist: every attribute path the schema declares, minus the
handful this runtime deliberately doesn't implement, plus a few
value-conditional checks for attributes only unsupported for one
specific value. A newly-specified attribute gets flagged
automatically, with no corresponding code change needed here.
Depends on an unreleased compose-go change; go.mod carries a
temporary replace to a fork branch until it's released.
Signed-off-by: Guillaume Lours <[email protected]>
