# ADR 0021: Match Registered Records During Resolution Inspection

## Status

Accepted.

## Date

2026-11-02

## Context

Application resolution can change fields within sequences. Treating every
sequence change as atomic prevents a field record from covering an individual
edit. Registered collection identities also provide a way to relate a final
record to its entry value when positions change, so inspection can retain the
correct source evidence without confusing it with a prior index occupant.

## Decision

Compare equal-length ordinary lists recursively by position during resolution
auditing. A length change requires coverage of the list or an ancestor. For a
collection with an applicable application identity registration, match entry and
final records only when both endpoints have valid, unique identities. A change
in identity order or membership requires list or ancestor coverage, while
surviving records retain their matched entry evidence. When matching is not
available, audit a changed list as a whole without introducing an early identity
failure. Final registration validation remains at its existing boundary.

Match only the resolution-entry and final snapshots, within the same registered
destination. Identity changes are removals and additions, not inferred renames.
Records and helpers address final positions; entry queries remain fixed to entry
coordinates, and helpers do not follow later moves automatically. A surviving
record takes precedence at a reused position; collection inspection retains
removed records' evidence, and absent historical positions remain inspectable.
New records do not inherit a previous occupant's history or explicitness.

Preserve recorded operations, source coordinates, sensitivity, and safe detached
inspection. Resolution comparison is separate from public effective diff, which
continues to present sequence changes atomically.

This extends resolution inspection under [ADR 0003](0003-preserve-presence-and-resolution-history.md)
while preserving the diff decision in [ADR 0010](0010-effective-configuration-diff.md),
source combination and identity rules in [ADR 0017](0017-collection-sequence-policy.md),
and lifecycle ordering in [ADR 0018](0018-cli-after-structural-resolution.md).

## Alternatives Considered

- **Keep all sequence changes atomic during resolution.** This forces whole-list
  records for independent field edits and does not identify a moved record's
  earlier evidence.
- **Infer identities for every list.** Similar values or conventional field
  names do not establish an application identity and could attach unrelated
  history to a final record.
- **Reconstruct every intermediate callback mutation.** This requires a new
  mutation history and implies an ordering that endpoint snapshots cannot prove.

## Consequences

Resolution auditing and inspection must share entry-to-final correspondence,
including explicit unmatched records, while preserving historical coordinates
and conservative sensitivity masking. Source assembly and public path types do
not change. The [implementation plan](../roadmap/implementation.md) tracks the
work; the [configuration contract](../config.md) owns implemented behavior.