[latex3-commits] [latex3/latex3] main: Error if \sys_ensure_debug: is used in doc. body (f5f4b7348)

[github at latex-project.org]

Repository : https://github.com/latex3/latex3
On branch  : main
Link       : https://github.com/latex3/latex3/commit/f5f4b73488dfb599f5ede2542385da43b8a9c47a

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

commit f5f4b73488dfb599f5ede2542385da43b8a9c47a
Author: Joseph Wright <joseph.wright at morningstar2.co.uk>
Date:   Mon Feb 19 20:46:53 2024 +0000

    Error if \sys_ensure_debug: is used in doc. body
    
    See #1442.


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

f5f4b73488dfb599f5ede2542385da43b8a9c47a
 l3kernel/CHANGELOG.md |  1 +
 l3kernel/l3msg.dtx    |  6 ++++++
 l3kernel/l3sys.dtx    | 11 ++++++++++-
 3 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/l3kernel/CHANGELOG.md b/l3kernel/CHANGELOG.md
index 8a5a2f0cf..dbb2f1ffa 100644
--- a/l3kernel/CHANGELOG.md
+++ b/l3kernel/CHANGELOG.md
@@ -10,6 +10,7 @@ this project uses date-based 'snapshot' version identifiers.
 ### Fixed
 - Restore `\__kernel_msg_...:nnx(xx)` for older `xparse` support
 - Prevent an infinite loop in `\debug_(on|off):` (issue \#1442)
+- Require `\sys_ensure_backend:` is used in the preamble (issue \#1442)
 
 ## [2024-02-18]
 
diff --git a/l3kernel/l3msg.dtx b/l3kernel/l3msg.dtx
index d1ed62fcc..f1451727f 100644
--- a/l3kernel/l3msg.dtx
+++ b/l3kernel/l3msg.dtx
@@ -2322,6 +2322,12 @@
     Run-time~backend~selection~may~only~be~carried~out~once~during~a~run.~
     This~second~attempt~to~set~them~will~be~ignored.
   }
+\msg_new:nnnn { sys } { load-debug-in-preamble }
+  { Load~debug~support~in~the~preamble. }
+  {
+    Debugging~requires~support~loaded~in~the~preamble: \\
+    Use~\sys_load_debug:~before~\begin{document}.
+  }
 \msg_new:nnnn { sys } { wrong-backend }
   { Backend~request~inconsistent~with~engine:~using~'#2'~backend. }
   {
diff --git a/l3kernel/l3sys.dtx b/l3kernel/l3sys.dtx
index 32de4338c..4662df727 100644
--- a/l3kernel/l3sys.dtx
+++ b/l3kernel/l3sys.dtx
@@ -691,7 +691,8 @@
 % \end{variable}
 %
 % \begin{macro}{\sys_load_debug:}
-%   Simple.
+%   The most complicated thing here is that we can only use
+%   \cs{__kernel_sys_configuration_load:n} in the preamble in \LaTeX{}.
 %    \begin{macrocode}
 \cs_new_protected:Npn \sys_load_debug:
   {
@@ -699,6 +700,14 @@
       { \__kernel_sys_configuration_load:n { l3debug } }
     \bool_gset_true:N \g_@@_debug_bool
   }
+\cs_if_exist:NT \@onefilewithoptions
+  {
+    \AtBeginDocument
+      {
+        \cs_gset_protected:Npn \sys_load_debug:
+          { \msg_error:nn { sys } { load-debug-in-preamble } }
+      }
+  }
 %    \end{macrocode}
 % \end{macro}
 %