[latex3-commits] [git/LaTeX3-latex3-latex3] master: Defensive coding (45e8ef244)

[Joseph Wright]

Repository : https://github.com/latex3/latex3
On branch  : master
Link       : https://github.com/latex3/latex3/commit/45e8ef244de40434531a068daa86824cdb711909

>---------------------------------------------------------------

commit 45e8ef244de40434531a068daa86824cdb711909
Author: Joseph Wright <joseph.wright at morningstar2.co.uk>
Date:   Fri Feb 21 18:36:47 2020 +0000

    Defensive coding


>---------------------------------------------------------------

45e8ef244de40434531a068daa86824cdb711909
 l3backend/l3backend-basics.dtx | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/l3backend/l3backend-basics.dtx b/l3backend/l3backend-basics.dtx
index 57757e7ee..d0d93d43c 100644
--- a/l3backend/l3backend-basics.dtx
+++ b/l3backend/l3backend-basics.dtx
@@ -159,7 +159,9 @@
   { \AtBeginDvi }
   { \use:n }
     {
-      \bool_if:NT \g__kernel_backend_header_bool
+      \bool_lazy_and:nnT
+        { \cs_if_exist_p:N \g__kernel_backend_header_bool }
+        { \g__kernel_backend_header_bool }
         { \__kernel_backend_literal:n { header = l3backend-dvips.pro } }
     }
 %    \end{macrocode}