Keep the lesson for the next incident
Document identity semantics
Record which fields identify an entity, which are source-local references, and which transformations are representation-only. Include examples of equivalent and distinct values, plus ambiguous cases that need review. This prevents a future maintainer from treating a convenient key as universally canonical.
Keep fixtures representative
Add compact fixtures for casing, padding, separators, source prefixes, reused values, and malformed inputs where they affected the incident. Assert both join recovery and non-merging. Retain labels and expected cardinality so tests explain the identity decision rather than only its string output.
Review recurrence and ownership
Assign an owner for source mapping and a separate owner for contract enforcement when needed. Review new identifier variants and join-cardinality changes on a defined cadence. Set a trigger for reopening investigation, and close the follow-up only when relevant sources show stable behavior.
What to carry forward
Close the learning record with identity definitions, source ownership, fixtures, and a recurrence trigger that a maintainer can use. Preserve unresolved variants as known review cases. The durable result is clearer identity reasoning and faster detection of join damage, not a promise that every source will converge.
Keep the decision with the work.
Use a Work Item in Aglet to record the problem, the evidence you have, and the next decision. Add an owner and priority, then keep updates in the discussion so the next person can follow the reasoning.
Create an account See the product workflow