Issue 2754 cleanup: Only complain once about any undead object

Embarrassingly, commit 2ea3798f3473a7dd02b85ac311aa9b8de4938c3c only
implemented the requisite fix in one place.  This replicates the code
for avoiding duplicate error messages at the second call place of
ly:parsed-undead-list! in lily.scm.

diff --git a/scm/lily.scm b/scm/lily.scm
index 35a16019a1e74df912b0166dbf1cf28e71594a19..74c5562f48067052df4f7d10b8872ac8260e8a79 100644 (file)
--- a/scm/lily.scm
+++ b/scm/lily.scm
@@ -843,10 +843,13 @@ PIDs or the number of the process."
          (ly:set-option 'debug-gc-assert-parsed-dead #t)
          (gc)
          (ly:set-option 'debug-gc-assert-parsed-dead #f)
-        (for-each
-         (lambda (x)
-           (ly:programming-error "Parsed object should be dead: ~a" x))
-         (ly:parsed-undead-list!))
+         (for-each
+          (lambda (x)
+            (if (not (hashq-ref gc-zombies x))
+                (begin
+                  (ly:programming-error "Parsed object should be dead: ~a" x)
+                  (hashq-set! gc-zombies x #t))))
+          (ly:parsed-undead-list!))
          (if (ly:get-option 'debug-gc)
              (dump-gc-protects)
              (ly:reset-all-fonts))