Status: accepted

Accepted — merged with intent to implement.

RFC 0101: Refuse every present source value outside the actor grammar

Accepted by the UWMD maintainers, 2026-10-19 (owner on #413: "accept your proposed disposition (any present value outside the §2.6 grammar is SRC-01; null is SRC-01 plus the retained warning)"). The RFC, its decisions and the implementation land together.

Summary

Format §2.6 already says an out-of-grammar _meta.provenance.source is SRC-01. The reference skipped every value that was not a non-empty string, so "", 0, false, [] and {} validated clean, and null drew only the completeness warning. This RFC states the rule for those values, and the reference now applies it: every present value outside the grammar is SRC-01. null is SRC-01 and keeps its existing META_FIELD_MISSING_SOURCE warning. Absence alone is unchanged.

Motivation

#413 (found certifying the independent Python implementation, #354):

provenance.source	Reference before	Python	This RFC
absent	META_FIELD_MISSING_SOURCE	same	unchanged
"", 0, false, [], {}	nothing	SRC-01	SRC-01
null	META_FIELD_MISSING_SOURCE	SRC-01	SRC-01 + META_FIELD_MISSING_SOURCE

A record whose actor is "" validated clean, though edit policies (Protocol §V.3) resolve on that field.

Proposed change

Format §2.6 gains one sentence after "An out-of-grammar source is SRC-01 (error)":

Any present value outside this grammar is out of grammar, including a non-string, the empty string and null. A null source also keeps its existing META_FIELD_MISSING_SOURCE warning, because a new allocation never silently removes an existing finding (RFC 0094). An absent source is not SRC-01; it stays with the completeness warning.

_overrides[].source already refuses non-strings with SRC-01 and is unchanged.

Compatibility analysis

Documents stating a non-string, empty or null source now fail validation. That is the defect. No corpus or example states one. The Python implementation already emits SRC-01; it adds the retained null warning on the #354 branch. No version is allocated (RFC 0091 D6).

Conformance impact

New conformance/source/06-empty-source, 07-null-source (also requires META_FIELD_MISSING_SOURCE) and 08-nonstring-source, indexed as verifier.

Reference implementation

validator.ts checkSourceVocabulary: skip only an undefined source; emit SRC-01 at _meta.provenance.source for any other non-string or empty value. Tests: validator.src.test.ts (six refused values, null with its warning, absence unchanged).

Alternatives considered

• Null as absence only (the reference's old reading). Rejected by the UWMD maintainers: a stated null is a present value outside the grammar.
• Drop the warning for null. Rejected: RFC 0094's rule keeps an existing finding when a new allocation also applies.

Unresolved questions

None.

Decisions

#	Question	Decision	Why
D1	Non-string / empty	SRC-01	§2.6 grammar; accepted resolution
D2	null	SRC-01 plus the retained META_FIELD_MISSING_SOURCE	Accepted resolution; RFC 0094 retention
D3	Absent	Unchanged (warning only)	Absence is completeness, not grammar

Prior art

RFC 0094 of this project (present-invalid metadata leaves; retained warnings).