[latex3-commits] [git/LaTeX3-latex3-latex3] master: Allow for repeated calls to load same backend (fixes #646) (f037f914e)

[Joseph Wright]

Repository : https://github.com/latex3/latex3
On branch  : master
Link       : https://github.com/latex3/latex3/commit/f037f914e41ee1b0c3d598600dd7a103a532c3cc

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

commit f037f914e41ee1b0c3d598600dd7a103a532c3cc
Author: Joseph Wright <joseph.wright at morningstar2.co.uk>
Date:   Mon Nov 4 10:07:33 2019 +0000

    Allow for repeated calls to load same backend (fixes #646)


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

f037f914e41ee1b0c3d598600dd7a103a532c3cc
 l3kernel/CHANGELOG.md | 4 ++++
 l3kernel/l3sys.dtx    | 5 ++++-
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/l3kernel/CHANGELOG.md b/l3kernel/CHANGELOG.md
index c8c1a1a24..977082625 100644
--- a/l3kernel/CHANGELOG.md
+++ b/l3kernel/CHANGELOG.md
@@ -7,6 +7,10 @@ this project uses date-based 'snapshot' version identifiers.
 
 ## [Unreleased]
 
+### Fixed
+
+- Handling of repeated loading of a backend (issue #646)
+
 ## [2019-10-28]
 
 ### Fixed
diff --git a/l3kernel/l3sys.dtx b/l3kernel/l3sys.dtx
index af09373f2..2437b4d31 100644
--- a/l3kernel/l3sys.dtx
+++ b/l3kernel/l3sys.dtx
@@ -395,7 +395,10 @@
   {
     \sys_finalise:
     \str_if_exist:NTF \c_sys_backend_str
-      { \__kernel_msg_error:nn { sys } { backend-set } }
+      {
+        \str_if_eq:VnF \c_sys_backend_str {#1}
+          { \__kernel_msg_error:nn { sys } { backend-set } }
+      }
       {
         \tl_if_blank:nF {#1}
           { \tl_set:Nn \g_@@_backend_tl {#1} }