Fix TOC: don't add links to non-existing labels in the .ps file

2 files changed, 19 insertions, 6 deletions

diff --git a/input/regression/page-links-nolabel.ly b/input/regression/page-links-nolabel.ly
new file mode 100644
index 0000000000..a8a1212350
--- /dev/null
+++ b/input/regression/page-links-nolabel.ly
@@ -0,0 +1,11 @@
+\version "2.13.60"
+
+\header {
+
+  texidoc = "Links to labels should not break if the label doesn't exist."
+
+}
+
+\book {
+  \markup { \with-link #'dummy \concat { "Link to non-existing label"  } }
+}
\ No newline at end of file
diff --git a/scm/output-ps.scm b/scm/output-ps.scm
index d1c0c419ed..c83b613cbd 100644
--- a/scm/output-ps.scm
+++ b/scm/output-ps.scm
@@ -262,12 +262,14 @@
 	     url))
 
 (define (page-link page-no x y)
-  (ly:format "~a ~a currentpoint vector_add  ~a ~a currentpoint vector_add ~a mark_page_link"
-	     (car x)
-	     (car y)
-	     (cdr x)
-	     (cdr y)
-	     page-no))
+  (if (number? page-no)
+    (ly:format "~a ~a currentpoint vector_add  ~a ~a currentpoint vector_add ~a mark_page_link"
+	       (car x)
+	       (car y)
+	       (cdr x)
+	       (cdr y)
+	       page-no)
+    ""))
 
 (define* (path thickness exps #:optional (cap 'round) (join 'round) (fill? #f))
   (define (convert-path-exps exps)