i18n: pin the Polish part labels; cross-reference the part-ID orders

1 files changed, 9 insertions, 0 deletions

diff --git a/internal/readings/offline.go b/internal/readings/offline.go
index c2c276b..608abd8 100644
--- a/internal/readings/offline.go
+++ b/internal/readings/offline.go
@@ -84,6 +84,15 @@ func efPartHeading(part, lang string) (id, heading string) {
 
 // ofPartOrder and efPartOrder are the display orders of each lectionary's
 // sections. They are the single source of truth for which part IDs exist.
+//
+// ofPartOrder's five modern IDs must remain the same *set* as
+// internal/render/render.go's modernPartOrder, which lists them in a
+// different, deliberate order (prefix-match determinism for
+// render.LocalizeHeading, unrelated to display order). Nothing enforces
+// that agreement mechanically -- internal/readings and internal/render do
+// not import each other (adding a cross-package test would create a new
+// dependency edge that does not exist today) -- so if a sixth modern part
+// is ever added here, add it to modernPartOrder too, by hand.
 var (
 	ofPartOrder = []string{"pierwsze_czytanie", "psalm", "drugie_czytanie", "aklamacja", "ewangelia"}
 	efPartOrder = []string{"epistola", "evangelium"}