OpenConceptLab/ocl_issues#1854 | References API can conditionally include resolved repo versions

[snyaggarwal]

No description provided.

[paynejd]

Nice, focused change — the INCLUDE_* opt-in pattern and the model-method extraction both match existing conventions. Two blockers before merge:

1. Tests. The conditional field toggle and the new get_resolved_repo_versions_serialized() both need coverage:

• ?includeResolvedRepoVersions=true → field present with expected shape
• default → field omitted from response
• reference with only system, only valueset, both, and neither

2. N×resolution performance. With the flag on, every reference triggers resolve_system_version + resolve_valueset_versions, each calling the full resolve_reference_expression algorithm (URL registry lookups, namespace match, version pinning). A collection with 100+ references will do 100+ resolution chains per list request. Worth addressing before this ships — a few options, roughly by effort:

• Request-scoped memoization (cheapest). Many refs in a collection point to the same system. Cache by (namespace, url, version) across the request — the expansion builder already does exactly this at core/collections/models.py:1363. Lift that helper into the serializer.
• Read from the expansion's M2M instead of re-resolving. Expansion.evaluated_source_versions / evaluated_collection_versions / explicit_* already hold resolution results. Prefetch rather than recompute. This is also closer to what ocl_issues#1854 asks for (the expansion-dropdown requirement implies resolved repo should be contextual to an expansion, not re-derived from reference fields) — may warrant a follow-up ticket.
• Fast path for the canonical-URL branch. Batch via Source.objects.filter(canonical_url__in=[...]) for refs that don't hit URL-registry logic, fall back per-row otherwise. More code paths to maintain — only worth it if memoization isn't enough.

My suggestion: add memoization here to unblock merge, and split the expansion-context question into a follow-up since it shapes the API contract.