RFC-019: Law End Dates (valid_to) and Expired-Reference Handling

Depends on

RFC-001 (YAML Schema Design Decisions), RFC-003 (Inversion of Control for Delegated Legislation), RFC-007 (Cross-Law Execution Model)

Required by

RFC-020 (Date-Aware Reference Resolution (as_of))

Context

Problem. Version selection filters on the lower bound only (valid_from <= calculation_date, newest wins - RFC-001 §5, RFC-003). There is no end date. So:

• The most recent version of any law is treated as valid forever. A law can only “end” by being superseded - never by expiring or being repealed.
• Real laws do end without a successor, in two ways:
  • intrinsic - the law’s own horizonbepaling: CEK23 “vervalt met ingang van 1 januari 2027” (art. 8.1 lid 2);
  • extrinsic - another instrument ends it: the Wet op de openluchtrecreatie was gefaseerd ingetrokken per 1 januari 2008; the Twm covid-19 measures vervielen per 20 mei 2022 after the Eerste Kamer rejected the goedkeuringswet for the fifth verlenging (17 mei 2022, dossier 36.042).
• Dependents break silently (“verweesde regelingen”). A regulation whose delegation basis disappears can no longer have effect (old Aanwijzing 243: van rechtswege vervallen; since 2018 Aanwijzing 6.24 prescribes explicit mede-intrekking instead - Stb. 2018, 362 executes it to the letter). Example: the Tijdelijke regeling maatregelen covid-19 was vervallen per the same date as the Twm. In regelrecht’s source.regulation model this is a dangling reference: the engine keeps computing on no-longer-valid law - a silent wrong answer.

Scope:

• valid_from/valid_to describe instrument validity (is the text in force?) - not the substantive scope a norm governs (e.g. CEK23 caps calendar-2023 deliveries), which stays in the rule’s own conditions and temporal metadata (RFC-001 §8).
• Article repeal is out of scope: repealing a single article is an ordinary amendment, already expressed by version succession (new consolidation → new version of the same $id, newest-wins). See Alternatives.
• Resolving an ended/changed law on purpose (eerbiedigende werking, statische verwijzing, ex tunc) is RFC-020 (date-aware resolution, as_of). RFC-019 covers only the global calculation_date.

Decision

Add a law-level valid_to, give version selection an inclusive upper bound, and report expired references honestly.

Grounding - the legislation this RFC is built on

1. valid_to: instrument end date

• Optional law-level field, mirroring valid_from (RFC-001 §5).
• Inclusive: the last calendar day the law is in force, matching BWB’s einddatum (“geldend t/m”). A statutory “vervalt met ingang van D” is exclusive → valid_to = D − 1.
• Only for genuine termination (the law vervalt or is ingetrokken):
  • not for ordinary succession - the next version’s valid_from already ends the old one;
  • a law repealed and replaced by a different $id still gets valid_to (newest-wins cannot end it).
• Two provenance modes for the date:
  • intrinsic - the law’s own vervalbepaling (CEK23 art. 8.1 lid 2). The only mode RFC-019 implements.
  • extrinsic - the date lives in another instrument (intrekkingswet, verlengings-KB, or open: Woo art. 10.2f lid 1). A cross-law “terminates” mechanism that derives the date from that instrument is future work; until then the harvested literal valid_to is a denormalised value with the terminating instrument as source of record.
• Boundary: validity is static metadata. This RFC never executes a law to decide whether another law is in force:
  • selection runs before execution, so derived validity has an ordering problem (you would have to execute a law to know which version is selectable);
  • a terminates-effect therefore binds early: at harvest time today (BWB already processed the terminating instrument into the final consolidation’s einddatum), at load/index time in the future mechanism - never at execution time (unlike overrides/implements, which resolve values, not validity);
  • load-time derivation matters for moving end dates: the Twm verlengings-KBs shifted the verval repeatedly; harvest-time literals would need a corpus rewrite on every change.
• Harvester rule: write valid_to from BWB einddatum only when the consolidation is the final one and the einddatum is finite (≠ the 9999-12-31 “still in force” sentinel). An intermediate consolidation’s einddatum is mere succession.

2. Version selection gains an upper bound

1. Among versions with valid_from <= calculation_date, select the newest (unchanged).
2. If that version has a valid_to and calculation_date > valid_to: the law is not in force → return nothing. No fall-through to an older version - a repealed law does not resurrect a prior version.

In force iff valid_from <= calculation_date <= valid_to (inclusive). Additive: laws without valid_to behave exactly as today.

3. Expired references: honest diagnostics

A reference whose target is not in force resolves to nothing - and the engine reports only what the data proves (RFC-015):

• Never “geen grondslag / zonder opvolger”: eerbiedigende werking, a statische verwijzing or an alternative grondslag may keep the law alive (→ RFC-020).
• The resolver exposes a typed reason (NotFound / NotYetInForce / EndedOn(date)); execution maps it to typed errors (LawNotFound / LawNotYetInForce / LawEnded with reference date and valid_to).
• Fatal vs. continue: a required reference that fails is an error (fail-fast, RFC-012); an optional one (required: false, RFC-003) yields a null/taint that propagates like UNTRANSLATABLE, recorded on the CrossLawReference trace node (RFC-007, RFC-013).

4. Receipt and conformance

• The receipt’s loaded_regulations (RFC-013) gains valid_to next to valid_from: the full validity window.
• A valid_to filtering case joins the Temporal conformance level (RFC-014).

Worked examples

A. Intrinsic end - Prijsplafond energie 2023 (CEK23, BWBR0047628)

Real corpus law, harvested from BWB: corpus/regulation/nl/ministeriele_regeling/subsidieregeling_bekostiging_plafond_energietarieven_kleinverbruikers_2023/2022-12-15.yaml. Modeled is what the articles literally vaststellen: plafondtarieven (art. 2.2), volumeplafonds (art. 2.3) and the vervaldatum (art. 8.1).

• End date grounded in art. 8.1 lid 2, full text: “Deze regeling vervalt met ingang van 1 januari 2027, met dien verstande dat zij van toepassing blijft op subsidies die voor die datum zijn verstrekt.” Art. 8.1 outputs the vervaldatum verbatim (the grounded source); the top-level valid_to is the denormalised inclusive last day (vervaldatum − 1). Deriving it automatically from the article output is the static-metadata boundary of §1.
• The staartzin is eerbiedigende werking - the RFC-020 bridge case: the regeling stays applicable to subsidies granted before 2027 even after its instrument end. valid_to correctly records the instrument end; §3 ensures the engine states only “no version in force on <datum>”, never “no longer applicable”. Resolving this regeling for a pre-2027 subsidie at a post-2026 date is exactly RFC-020’s as_of case.
• Verified with the evaluate binary:
  • date: 2023-06-01 → plafondtarief_elektriciteit: 0.24755, volumeplafond_elektriciteit: 2900, vervaldatum: 2027-01-01;
  • date: 2027-06-01 → fails with the data fact: no version in force on 2027-06-01, last in force until 2026-12-31 (§2, §3).
• Faithfulness: the regeling is a subsidie aan leveranciers (art. 2.1 lid 1); the supplier subsidy formulas of art. 3.1-3.5 (volume-capped verbruik × (contracttarief − plafondtarief), plus TUK, minus brutomarge-correctie) are not modeled - they need bijlage data and supplier-level aggregates. No article computes a consumer-facing “korting”. The cap’s substantive scope (calendar 2023) is separate from the instrument validity (text in force until 2027).

B. The limits case - dynamic, KB-determined, per-provision end (Twm)

The Tijdelijke wet maatregelen covid-19 shows what a static law-level valid_to deliberately does not cover (§1 boundary):

• The end date is not in the law. Art. VIII lid 1: the inserted Hoofdstuk Va Wpg vervalt three months after entry into force; lid 3 lets a KB extend it - or designated parts - by at most three months at a time (“steeds ten hoogste drie maanden”). After repeated verlengings-KBs the measures lapsed per 20 mei 2022, when the goedkeuringswet for the fifth verlenging was rejected. Authoring valid_to: '2022-05-19' would be invented - not grounded in the Twm’s own text.
• The verval is per-provision. Parts not extended lapsed separately (e.g. the avondklok-grondslag earlier); a single law-level date is too coarse.
• The clean, grounded intrinsic case is CEK23 (example A): one literal vervaldatum for the whole regeling.

C. Expired dependent - orphaned reference

• Regulation R reads an output of law B (source: { regulation: B, output: … }); B carries valid_to.
• At a calculation_date after B’s end: B resolves to nothing, R yields no outcome, and execution reports “geen versie van B van kracht op <datum>; laatst geldig t/m <valid_to>” - instead of computing on the repealed B.
• Tested end-to-end in features/einddatum.feature (test laws test_einddatum / test_einddatum_afnemer).

Testing

New cucumber-rs scenarios in features/einddatum.feature (test laws mirroring test_untranslatables):

1. valid_to upper bound: resolves before and on the (inclusive) end date; fails with the data fact after it (no fall-through).
2. expired cross-reference: dependent R references ended law B; after B’s valid_to, R yields no outcome and the error states the fact (§3).

Plus unit tests on the selection rule (SelectionReason cases) and, as follow-up, a valid_to case in the Temporal conformance level (RFC-014).

Why

Benefits

• Expresses laws that end. Twm, CEK23 and WOR become representable; the latest version is no longer eternal.
• No silent wrong answers. A reference to an ended law surfaces honestly.
• Small and additive. One field + an upper bound + an honest diagnostic; laws without valid_to are unchanged.

Tradeoffs

• Authoring discipline: valid_to only for genuine ends (mirroring RFC-003’s explicit valid_from convention for implementing regulations).
• Receipt/conformance churn: one new field, one new case.

Alternatives Considered

• valid_to on every version (mirroring the next version’s valid_from). Rejected: on ordinary succession the law text contains no end date - it would be invented, violating groundedness. Newest-wins already ends the old version implicitly.
• Article-level valid_from/valid_to. Rejected: repealing a single article is an ordinary amendment, already expressed by version succession. Stb. 2018, 362 art. 2 (“Artikel 76 van de Gezondheids- en welzijnswet voor dieren vervalt met ingang van 1 november 2018”) materialises as the Gwwd’s 2018-11-01 consolidation with art. 76 as a “Vervallen” placeholder; a post-repeal lookup fails with the OutputNotFound data fact, while historical dates still resolve the older version.
• Engine infers “repealed/no successor” and reports it. Rejected: violates RFC-015 (zero domain knowledge) and is unprovable - eerbiedigende werking or an alternative grondslag may keep the law alive.
• Fall through to an older version once the latest has ended. Rejected: repeal does not resurrect a prior version; if an earlier version still applies, that is RFC-020’s explicit date-aware case, not an implicit fallback.

Implementation Notes

• Schema: additive law-level valid_to; new minor schema version. Literal dates only (no #-references): the engine reads valid_to as static metadata, so a reference would be silently ignored.
• Engine: ArticleBasedLaw.valid_to; inclusive upper bound + no-fall-through in select_version_for_date; typed SelectionReason mapped to the §3 errors; malformed calculation dates rejected up front (no selection bypass); receipt records valid_to.
• Harvester: valid_to from BWB einddatum, only for a final consolidation with a finite einddatum.

References

• RFC-001 YAML Schema · RFC-003 IoC/temporal filter · RFC-007 Cross-Law Execution · RFC-012 Untranslatables · RFC-013 Execution Provenance · RFC-014 Conformance · RFC-015 Engine Policy
• RFC-020: date-aware reference resolution (as_of) - eerbiedigende werking, statische verwijzing, ex nunc/ex tunc, lex mitior
• Legislation: see the Grounding table above. Aanwijzingen voor de regelgeving: official text BWBR0005730, deep links via kcbr.nl - 6.24 (vervallen uitvoeringsregelingen; explicit mede-intrekking since 2018), 6.25 (uitgewerkte regelingen), old 243 (pre-2018: van rechtswege vervallen)
• Glossary of Dutch Legal Terms