From f792fed2ff519ffac1436e41e47cc0504d253a77 Mon Sep 17 00:00:00 2001
From: Friedemann Kleint <Friedemann.Kleint@qt.io>
Date: Tue, 5 Mar 2019 14:25:45 +0100
Subject: [PATCH] XCB/libxkbcommon input context: Fix crash when invalid local
 is set

Fall back to querying the locale.

Fixes: QTBUG-74216
Change-Id: Ibd60572454741e64f649ecc3e37f593a8e2b2bda
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
---
 .../compose/qcomposeplatforminputcontext.cpp                  | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp b/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp
index 6b9687c22d..57fe7c2fa2 100644
--- a/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp
+++ b/src/plugins/platforminputcontexts/compose/qcomposeplatforminputcontext.cpp
@@ -70,7 +70,9 @@ void QComposeInputContext::ensureInitialized()
     }
 
     m_initialized = true;
-    const char *const locale = setlocale(LC_CTYPE, "");
+    const char *locale = setlocale(LC_CTYPE, "");
+    if (!locale)
+        locale = setlocale(LC_CTYPE, nullptr);
     qCDebug(lcXkbCompose) << "detected locale (LC_CTYPE):" << locale;
 
     m_composeTable = xkb_compose_table_new_from_locale(m_XkbContext, locale, XKB_COMPOSE_COMPILE_NO_FLAGS);