Apply the same psalm-number/antiphon split to Vespers' psalmody override

Mirrors the Lauds fix: a proper override's psalm numbers stay gated at
duplex-majus+, while its antiphons still layer onto the ferial weekday's
own numbers below that rank, paired by group index.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018sPkfGLiq58pmmDoBWH5UX

src/hours/lauds.ts

@@ -50,18 +50,18 @@ interface PsalmodyBlock {
 const laudsAntiphons = laudsAntiphonsData as Record<Weekday, PsalmodyBlock>;
 
 /**
- * Two independent tiers, tried in order:
+ * Two independent tiers, tried in order, for a duplex-majus+ (or named-
+ * temporal) feast eligible to substitute its own psalm *numbers*, not
+ * just its antiphons — see resolvePsalmody below for the sub-duplex-majus
+ * case, which merges tier 1's antiphon text onto the ferial numbers
+ * instead of calling this at all:
  *
- * 1. **Proper** — this feast's own authored antiphons (per-feast, not
- *    per-Common — explicit choice), eligible at *any rank* via
- *    resolve-common.ts's getPsalmodyProperOverrideId. A saint's own real
- *    proper text is never gated behind rank — see that function's own
- *    doc comment for why this used to be wrongly bundled with tier 2's
- *    gate (fixed 2026-08-29).
- * 2. **Common category** — a generic-by-category substitute, still
- *    gated at duplex-majus+ via getOfficeOverrideId (a real, distinct,
- *    weaker tier: same conventional psalm numbers, not this feast's own
- *    text).
+ * 1. **Proper** — this feast's own authored antiphons+numbers (per-feast,
+ *    not per-Common — explicit choice), via resolve-common.ts's
+ *    getPsalmodyProperOverrideId.
+ * 2. **Common category** — a generic-by-category substitute, gated at
+ *    duplex-majus+ via getOfficeOverrideId (a real, distinct, weaker
+ *    tier: same conventional psalm numbers, not this feast's own text).
  *
  * Falls back to `undefined` — the plain weekday default — for an eligible
  * feast with no override authored yet in either tier, same honest
@@ -86,6 +86,35 @@ function getPsalmodyOverrideFor(day: LiturgicalDay): LaudsPsalmodyOverride | und
   return categoryId ? getLaudsCommonOverride(categoryId) : undefined;
 }
 
+/**
+ * Below duplex-majus, a feast's own proper psalm *numbers* never
+ * substitute for the ferial cycle (real Tridentine/Monastic rubric: only
+ * a strong-enough feast gets proper psalms — a lesser one keeps the
+ * ferial psalmody unchanged and gets its own proper text only at the
+ * Benedictus antiphon and chapter/responsory/hymn/versicle bundle,
+ * already-separate rank-agnostic mechanisms in resolve-common.ts). But a
+ * saint's own authored antiphon text for these same psalm slots is still
+ * real content worth showing (getPsalmodyProperOverrideId's own "any
+ * rank" eligibility) — so it's layered onto the ferial numbers here
+ * instead of being discarded outright.
+ *
+ * A proper override's own group count doesn't always match the ferial
+ * weekday's (e.g. Saturday's Monastic 2-group split vs. the usual 3), so
+ * pairing is by index against `ferial`'s own groups/canticle/laudate:
+ * ferial's numbers (and canticle id/split) always win; each slot's
+ * antiphon comes from `proper`'s same-index entry when one exists, else
+ * stays ferial's own. Any extra `proper` groups beyond `ferial`'s count
+ * are simply unused — confirmed with the user 2026-08-29 rather than
+ * assumed, since there's no rubric covering this specific mismatch.
+ */
+function mergeFerialNumbersWithProperAntiphons(ferial: PsalmodyBlock, proper: LaudsPsalmodyOverride): PsalmodyBlock {
+  return {
+    groups: ferial.groups.map((g, i) => ({ psalms: g.psalms, antiphon: proper.groups[i]?.antiphon ?? g.antiphon })),
+    canticle: { ...ferial.canticle, antiphon: proper.canticle?.antiphon ?? ferial.canticle.antiphon },
+    laudate: { antiphon: proper.laudate?.antiphon ?? ferial.laudate.antiphon },
+  };
+}
+
 // Mon-Fri share one capitulum verbatim (confirmed against the live engine
 // — see lauds-capitulum-ferial.yml); Sunday and Saturday each have their
 // own.
@@ -149,10 +178,21 @@ function canticleText(canticleId: string, slice?: [number, number]): ResolvedTex
 }
 
 /** Ps 66 through the Laudate psalms — see hours/types.ts's 'lauds-psalmody'
- * doc comment for the scope, and getPsalmodyOverrideFor above for when the
- * plain weekday default below gets substituted. */
+ * doc comment for the scope, getPsalmodyOverrideFor above for when the
+ * plain weekday default gets substituted wholesale (numbers and
+ * antiphons together, duplex-majus+ only), and
+ * mergeFerialNumbersWithProperAntiphons for the sub-duplex-majus case
+ * (ferial numbers, a saint's own antiphon text layered on top). */
 function resolvePsalmody(day: LiturgicalDay): ResolvedPart[] {
-  const wd = getPsalmodyOverrideFor(day) ?? laudsAntiphons[day.weekday];
+  const ferial = laudsAntiphons[day.weekday];
+  let wd: PsalmodyBlock;
+  if (getOfficeOverrideId(day)) {
+    wd = getPsalmodyOverrideFor(day) ?? ferial;
+  } else {
+    const properId = getPsalmodyProperOverrideId(day);
+    const proper = properId ? getLaudsSaintOverride(properId) : undefined;
+    wd = proper ? mergeFerialNumbersWithProperAntiphons(ferial, proper) : ferial;
+  }
   const winner = resolveOfficeWinner(day);
   const opening = (antiphon: BilingualText) => openingAntiphon(verifiedText(antiphon), winner);
   const parts: ResolvedPart[] = [

src/hours/vespers.ts

@@ -72,15 +72,18 @@ function psalmParts(group: VespersGroup, day: LiturgicalDay): ResolvedPart[] {
 }
 
 /** Two independent tiers, tried in order — same split as hours/lauds.ts's
- * own getPsalmodyOverrideFor, see its doc comment for the full rationale:
+ * own getPsalmodyOverrideFor, see its doc comment for the full rationale.
+ * Substitutes psalm *numbers*, not just antiphons, so only applies for a
+ * duplex-majus+ (or named-temporal) feast — see resolvePsalmody below for
+ * the sub-duplex-majus case, which merges tier 1's antiphons onto the
+ * ferial numbers instead of calling this at all:
  *
- * 1. **Proper** — this feast's own authored psalmody, eligible at *any
- *    rank* via resolve-common.ts's getPsalmodyProperOverrideId (a saint's
- *    own real proper text is never gated behind rank).
+ * 1. **Proper** — this feast's own authored psalmody, via resolve-
+ *    common.ts's getPsalmodyProperOverrideId.
  * 2. **Common category** — per hours/vespers-psalmody-overrides.ts's own
  *    doc comment, genuinely per-Common here (the psalm *numbers*
  *    themselves differ by Common, not just the antiphons, unlike Lauds)
- *    — still gated at duplex-majus+ via getOfficeOverrideId.
+ *    — gated at duplex-majus+ via getOfficeOverrideId.
  *
  * Eligibility follows the evening's governing `day` (same
  * resolveOfficeWinner-based test as the chapter/responsory/hymn/versicle
@@ -98,6 +101,18 @@ function getPsalmodyOverrideFor(day: LiturgicalDay): VespersDay | undefined {
   return categoryId ? getVespersCommonOverride(categoryId) : undefined;
 }
 
+/** Below duplex-majus, mirrors hours/lauds.ts's identical
+ * mergeFerialNumbersWithProperAntiphons — real proper psalm numbers stay
+ * gated at duplex-majus+, but a saint's own authored antiphon text is
+ * still layered onto the ferial numbers when authored, paired by index
+ * against `ferial`'s own groups (extra `proper` groups beyond `ferial`'s
+ * count go unused — same confirmed convention as Lauds). */
+function mergeFerialNumbersWithProperAntiphons(ferial: VespersDay, proper: VespersDay): VespersDay {
+  return {
+    groups: ferial.groups.map((g, i) => ({ psalms: g.psalms, antiphon: proper.groups[i]?.antiphon ?? g.antiphon })),
+  };
+}
+
 /** The 4 weekday-variable psalm groups — no fixed leading/trailing psalm
  * the way Lauds has (Ps 66 / the Laudate psalms); Vespers is just these 4
  * groups in sequence, substituted wholesale by getPsalmodyOverrideFor
@@ -110,7 +125,15 @@ function getPsalmodyOverrideFor(day: LiturgicalDay): VespersDay | undefined {
  * propers. `day` is still threaded into psalmParts for antiphon-fullness
  * resolution, which does care who governs tonight. */
 function resolvePsalmody(day: LiturgicalDay, weekday: Weekday): ResolvedPart[] {
-  const wd = getPsalmodyOverrideFor(day) ?? vespersAntiphons[weekday];
+  const ferial = vespersAntiphons[weekday];
+  let wd: VespersDay;
+  if (getOfficeOverrideId(day)) {
+    wd = getPsalmodyOverrideFor(day) ?? ferial;
+  } else {
+    const properId = getPsalmodyProperOverrideId(day);
+    const proper = properId ? getVespersSaintOverride(properId) : undefined;
+    wd = proper ? mergeFerialNumbersWithProperAntiphons(ferial, proper) : ferial;
+  }
   return wd.groups.flatMap((group) => psalmParts(group, day));
 }