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

1 files changed, 8 insertions, 0 deletions

diff --git a/internal/render/render.go b/internal/render/render.go
index c744aac..3437396 100644
--- a/internal/render/render.go
+++ b/internal/render/render.go
@@ -29,6 +29,14 @@ func versionLabel(version, lang string) string {
 // than ranging over i18n.UI.PartLabel (a map, so Go randomises its
 // iteration order). None of the five labels is a prefix of another, so the
 // order never changes which one matches, only determinism.
+//
+// Its *set* of five IDs must match internal/readings/offline.go's
+// ofPartOrder, which lists the same modern IDs in a different, deliberate
+// order (display order, unrelated to this package's prefix-match need).
+// Nothing enforces that agreement mechanically -- internal/render and
+// internal/readings 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 to ofPartOrder, add it here too, by hand.
 var modernPartOrder = []string{"pierwsze_czytanie", "drugie_czytanie", "psalm", "aklamacja", "ewangelia"}
 
 // LocalizeHeading swaps a modern (niedziela.pl) section heading's leading