Fix undefined behavior in ProString/ProKey::appendTo

We must not pass null pointers to memcpy.

Pick-to: 6.0
Fixes: QTBUG-88780
Change-Id: Ic1d77b4672310a3f6d0d4fbee5f2889e3e4d219d
Reviewed-by: Lars Knoll <lars.knoll@qt.io>

1 files changed, 4 insertions, 0 deletions

diff --git a/qmake/library/proitems.h b/qmake/library/proitems.h
index 6c1d48944a..f7eef39988 100644
--- a/qmake/library/proitems.h
+++ b/qmake/library/proitems.h
@@ -233,6 +233,8 @@ template <> struct QConcatenable<ProString> : private QAbstractConcatenable
     static inline void appendTo(const ProString &a, QChar *&out)
     {
         const auto n = a.size();
+        if (!n)
+            return;
         memcpy(out, a.toQStringView().data(), sizeof(QChar) * n);
         out += n;
     }
@@ -247,6 +249,8 @@ template <> struct QConcatenable<ProKey> : private QAbstractConcatenable
     static inline void appendTo(const ProKey &a, QChar *&out)
     {
         const auto n = a.size();
+        if (!n)
+            return;
         memcpy(out, a.toQStringView().data(), sizeof(QChar) * n);
         out += n;
     }