merge: RG 72's Christmas Time boundary, and the season/slug split it needed

Separates the liturgical season from the season that names slugs and numbers
weeks, so the boundary could move without renaming every slug in the window.

1 files changed, 30 insertions, 7 deletions

diff --git a/internal/calendar/oracle_ef_test.go b/internal/calendar/oracle_ef_test.go
index b74d935..b765a34 100644
--- a/internal/calendar/oracle_ef_test.go
+++ b/internal/calendar/oracle_ef_test.go
@@ -249,11 +249,18 @@ var efAllowList = []efAllow{
 		// defects, and not touched here: efSeason is a season-boundary
 		// function with much wider reach than any of the seven, and changing
 		// it is out of this task's scope.
+		// CORRECTED 2026-08-18: lectio now follows RG 72 and reads 6-13 January
+		// as Christmas Time, so this divergence has CHANGED SIDES. It is
+		// missalemeum that calls those days "time after Epiphany" now, and
+		// what this excuses is a SEASON difference rather than the colour one
+		// it was written for -- the colour follows correctly once the season
+		// is right, which is why the six colour rows this used to cover are
+		// simply gone.
 		match: func(date string, day time.Time, o efOracleDay) bool {
 			return day.Month() == time.January && day.Day() >= 6 && day.Day() <= 13
 		},
-		field:  "colour",
-		reason: "RG 72-73/RG 119(a): 6-13 Jan is Christmastide, not lectio's time-after-Epiphany reading (efSeason, not one of the seven defects; see colitur rules-register.md §3c item 1)",
+		field:  "season",
+		reason: "RG 72: Christmas Time runs 'usque ad diem 13 ianuarii inclusive', so 6-13 Jan is the Epiphany section OF Christmas Time; missalemeum reads it as time after Epiphany (colitur C1)",
 	},
 	{
 		// RG 33: "Vigilia II aut III classis penitus omittitur, si occurrat in
@@ -330,7 +337,7 @@ func TestOracleEF(t *testing.T) {
 	}
 	sort.Strings(dates)
 
-	var seasonMiss, rankMiss, colourMiss, rankAllowed, colourAllowed, skipped, total int
+	var seasonMiss, seasonAllowed, rankMiss, colourMiss, rankAllowed, colourAllowed, skipped, total int
 	shownSeason, shownRank, shownColour := 0, 0, 0
 	for _, date := range dates {
 		od := oracle[date]
@@ -356,10 +363,25 @@ func TestOracleEF(t *testing.T) {
 		if want == "" {
 			skipped++
 		} else if got.Season != want {
-			seasonMiss++
-			if shownSeason < 40 {
-				t.Errorf("%s: EF season got %q want %q (from %q)", date, got.Season, want, src)
-				shownSeason++
+			// The season axis consults the allow-list, and an excused day is
+			// NOT counted in seasonMiss. Neither was true before: until the
+			// RG 72 boundary was fixed no cited divergence had ever been a
+			// SEASON one -- the 6-13 January window showed up as a colour
+			// difference, because the wrong season produced the wrong colour
+			// too. With the season right the colour follows, and what is left
+			// is a season difference with no way to say "this one is known".
+			// Counting an excused day in seasonMiss would be worse than
+			// useless: the threshold below is a t.Fatalf, so the allow-list
+			// would print a reason and fail the suite anyway.
+			if ok, why := efAllowed(date, day, od, "season"); ok {
+				seasonAllowed++
+				t.Logf("[allow-listed] %s: EF season got %q want %q — %s", date, got.Season, want, why)
+			} else {
+				seasonMiss++
+				if shownSeason < 40 {
+					t.Errorf("%s: EF season got %q want %q (from %q)", date, got.Season, want, src)
+					shownSeason++
+				}
 			}
 		}
 
@@ -419,6 +441,7 @@ func TestOracleEF(t *testing.T) {
 	t.Logf("EF oracle: %d checked, %d skipped(unmapped), %d season mismatches, "+
 		"%d rank mismatches (%d allow-listed), %d colour mismatches (%d allow-listed)",
 		total, skipped, seasonMiss, rankMiss, rankAllowed, colourMiss, colourAllowed)
+	t.Logf("EF oracle: %d season mismatches allow-listed", seasonAllowed)
 	if seasonMiss > 0 {
 		t.Fatalf("%d/%d EF season mismatches vs missalemeum — temporalEF is wrong", seasonMiss, total)
 	}