[arxhr007]

What this PR does

Adds a consistency check for restart and deploy.restart_policy in loader/validate.go, next to the existing scale/deploy.replicas and cpus/deploy.resources.limits.cpus checks. When both attributes are set, they must not contradict each other — the values are compared after mapping to the engine vocabulary, so restart: always + condition: any is accepted as the same policy.

Attributes left unset on one side are treated as complements, not conflicts: restart: on-failure + max_attempts: 3 is allowed (the deploy policy supplies what restart did not set), and a restart_policy with only delay/window stays valid — preserving the complementary cases that motivated the merge-field-by-field fix in docker/compose.

Rejected examples:

• restart: unless-stopped + condition: on-failure → can't set distinct values on 'restart' and 'deploy.restart_policy.condition'
• restart: on-failure:3 + condition: any → same error (the merged always + retry count of 3 would also be rejected by the engine at container creation)
• restart: on-failure:3 + condition: on-failure + max_attempts: 5 → can't set distinct values on 'restart' and 'deploy.restart_policy.max_attempts'

Related

Proposed by @ndeloof on docker/compose#14459 as the compose-go half of the fix for docker/compose#14383 — with the loader rejecting distinct values, the compose-side merge only has to deal with consistent or unset attributes.

Testing done

• New spec-locking test TestRestartConsistentWithDeployRestartPolicy in loader/tests/restart_test.go: 8 cases covering vocabulary equivalence (any/always, none/no), matching condition + attempts, complementary/unset attributes, and each distinct-value rejection
• go test ./loader/... — full loader suite passes
• golangci-lint run — 0 issues

AI disclosure

This contribution was prepared by an AI agent (Devin, Cognition) acting on a human's behalf. The human submitter may not have independently reviewed or tested the change.

[arxhr007]

Closing — #989 (filed within the same second, by @ndeloof) supersedes this: it carries the same contradiction check with identical error messages, plus the loader-side reconciliation that folds the merged outcome into restart itself, which is the better long-term design. The complementary cases I tested here (delay-only, no/none equivalence, deploy-supplied max_attempts) are all covered there too.

docker/compose#14459 stays relevant in the meantime — as noted in #989's description, it does the field-by-field merge for current compose-go versions.