Proposal: Archive Validity and Reader Recovery

Status

Accepted for OAA 1.0

Summary

Separate archive validity, recoverable content, advisory warnings, unsupported versions, reader capacity limits, and destination-specific limitations.

Motivation

A reader can recover useful records from a damaged archive without making that archive valid. Conversely, a valid archive may exceed a particular reader’s configured capacity.

Specification Changes

• A violation of an archive-level MUST or MUST NOT requirement makes the archive invalid.
• Readers MAY recover usable content from invalid input, subject to all safe-reading requirements. Recovery functionality is optional and MUST NOT be a core conformance prerequisite.
• Readers performing recovery MUST identify the input as invalid and report known skipped or lost content; recovery MUST NOT be presented as a complete conforming import.
• A referenced embedded file that is missing makes the archive invalid, even when artwork metadata can be recovered.
• Failure to meet a SHOULD recommendation produces an advisory warning rather than invalidity solely on that basis.
• Exceeding a reader’s configured resource limits MUST be reported as an inability to process the input, not as proof that the archive violates the format.
• Readers MUST distinguish unsupported schema versions and destination-specific extraction limitations from archive invalidity. An unsupported version alone does not establish whether the archive conforms to that version’s contract.
• Readers that stop before completing validation MUST NOT report the archive as fully validated.

Compatibility Impact

OAA 1.0 conformance language, validator severity, and diagnostics must agree on these distinctions. Recovery does not relax the valid-archive contract.

Examples

A missing scan makes an archive invalid, but a reader can salvage the title and credits with an explicit recovery report. A mimetype entry that is not first produces a warning. A configured archive-size limit can stop reading without establishing invalidity.

Open Questions

None for this decision. Diagnostic alignment and fixtures remain part of the 1.0 integration work.