X-Git-Url: https://git.donarmstrong.com/?a=blobdiff_plain;f=lily%2Fbook-scheme.cc;h=c63f47dd078b49597c22ee8aeaef54368cb564d6;hb=5d84bfad4626892bcffd05adcced53c8a2329047;hp=af0cb6263221e745f6b5d27d2dce49ba6fa9668c;hpb=67cd07e55d5ec908c246ae543e480d367b61d6b3;p=lilypond.git

diff --git a/lily/book-scheme.cc b/lily/book-scheme.cc
index af0cb62632..c63f47dd07 100644
--- a/lily/book-scheme.cc
+++ b/lily/book-scheme.cc
@@ -152,7 +152,7 @@ LY_DEFINE (ly_book_header, "ly:book-header",
 {
   LY_ASSERT_SMOB (Book, book, 1);
   Book *b = unsmob<Book> (book);
-  return b->header_ ? b->header_ : SCM_BOOL_F;
+  return ly_is_module (b->header_) ? b->header_ : SCM_BOOL_F;
 }
 
 LY_DEFINE (ly_book_set_header_x, "ly:book-set-header!",