Set up backend right at the start of \document (fixes #657)

latex3 · Jan 6, 2020 · 26da686 · 26da686
1 parent 564cbb0
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diff --git a/l3kernel/CHANGELOG.md b/l3kernel/CHANGELOG.md
@@ -13,6 +13,9 @@ this project uses date-based 'snapshot' version identifiers.
 ### Changed
 - Distribute LaTeX3 News
 
+### Fixed
+- Set backend at the beginning of `\document` (see #657)
+
 ## [2019-11-07]
 
 ### Fixed

diff --git a/l3kernel/expl3.dtx b/l3kernel/expl3.dtx
@@ -1322,13 +1322,17 @@
   }
 %    \end{macrocode}
 %
-%  A backend has to be in place by the start of the document.
+%  A backend has to be in place by the start of the document: this has to be
+%  before global options are checked for use. The odd group stuff avoids
+%  needing to actually patch \tn{document}.
 %    \begin{macrocode}
 %<*2ekernel>
-\AtBeginDocument
+\tl_put_left:Nn \document
   {
+    \endgroup
     \str_if_exist:NF \c_sys_backend_str
       { \sys_load_backend:n { } }
+    \begingroup
   }
 %</2ekernel>
 %<*!2ekernel>