From 2afc6ee0e5c2dae1f484484a2761ba52a32f1685 Mon Sep 17 00:00:00 2001
From: Petro Vashchuk <stalkernoid@gmail.com>
Date: Mon, 17 Jan 2022 16:38:53 +0200
Subject: [PATCH] Bug 29684: add honeypot to catch other warnings in the future

---
 C4/Templates.pm | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/C4/Templates.pm b/C4/Templates.pm
index d41c9b534e..53e1dc5073 100644
--- a/C4/Templates.pm
+++ b/C4/Templates.pm
@@ -113,6 +113,12 @@ sub output {
     $vars->{opaclayoutstylesheet} =
         C4::Context->preference('opaclayoutstylesheet');
 
+    if(exists $self->{VARS}{lang}) {
+        warn "Preventing \$template->lang='" . ($self->{vars}{lang}//'-undef-')
+            . "' to be overwritten by template->{VARS}{lang}='" . ($self->{VARS}{lang}//'-undef-') . "'";
+        delete $self->{VARS}{lang};
+    }
+
     # add variables set via param to $vars for processing
     $vars = { %$vars, %{ $self->{VARS} } };
 
-- 
2.31.1