4 files changed, 24 insertions, 4 deletions
diff --git a/src/corelib/text/qcollator_icu.cpp b/src/corelib/text/qcollator_icu.cpp
index 8acda45070..0dca1ee9c9 100644
--- a/src/corelib/text/qcollator_icu.cpp
+++ b/src/corelib/text/qcollator_icu.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2016 The Qt Company Ltd.
+** Copyright (C) 2020 The Qt Company Ltd.
 ** Copyright (C) 2013 Aleix Pol Gonzalez <aleixpol@kde.org>
 ** Contact: https://www.qt.io/licensing/
 **
@@ -109,6 +109,11 @@ void QCollatorPrivate::cleanup()
 
 int QCollator::compare(QStringView s1, QStringView s2) const
 {
+    if (!s1.size())
+        return s2.size() ? -1 : 0;
+    if (!s2.size())
+        return +1;
+
     if (d->dirty)
         d->init();
 
diff --git a/src/corelib/text/qcollator_macx.cpp b/src/corelib/text/qcollator_macx.cpp
index 071d7c048f..cb8e073d4a 100644
--- a/src/corelib/text/qcollator_macx.cpp
+++ b/src/corelib/text/qcollator_macx.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Aleix Pol Gonzalez <aleixpol@kde.org>
+** Copyright (C) 2020 Aleix Pol Gonzalez <aleixpol@kde.org>
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -94,6 +94,11 @@ void QCollatorPrivate::cleanup()
 
 int QCollator::compare(QStringView s1, QStringView s2) const
 {
+    if (!s1.size())
+        return s2.size() ? -1 : 0;
+    if (!s2.size())
+        return +1;
+
     if (d->dirty)
         d->init();
     if (!d->collator)
diff --git a/src/corelib/text/qcollator_posix.cpp b/src/corelib/text/qcollator_posix.cpp
index 9cbc539ebe..ffcd214cfb 100644
--- a/src/corelib/text/qcollator_posix.cpp
+++ b/src/corelib/text/qcollator_posix.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Aleix Pol Gonzalez <aleixpol@kde.org>
+** Copyright (C) 2020 Aleix Pol Gonzalez <aleixpol@kde.org>
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -75,6 +75,11 @@ static void stringToWCharArray(QVarLengthArray<wchar_t> &ret, QStringView string
 
 int QCollator::compare(QStringView s1, QStringView s2) const
 {
+    if (!s1.size())
+        return s2.size() ? -1 : 0;
+    if (!s2.size())
+        return +1;
+
     if (d->isC())
         return s1.compare(s2, caseSensitivity());
     if (d->dirty)
diff --git a/src/corelib/text/qcollator_win.cpp b/src/corelib/text/qcollator_win.cpp
index 9d81de882f..54f57f1d24 100644
--- a/src/corelib/text/qcollator_win.cpp
+++ b/src/corelib/text/qcollator_win.cpp
@@ -1,6 +1,6 @@
 /****************************************************************************
 **
-** Copyright (C) 2013 Aleix Pol Gonzalez <aleixpol@kde.org>
+** Copyright (C) 2020 Aleix Pol Gonzalez <aleixpol@kde.org>
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtCore module of the Qt Toolkit.
@@ -89,6 +89,11 @@ void QCollatorPrivate::cleanup()
 
 int QCollator::compare(QStringView s1, QStringView s2) const
 {
+    if (!s1.size())
+        return s2.size() ? -1 : 0;
+    if (!s2.size())
+        return +1;
+
     if (d->isC())
         return s1.compare(s2, d->caseSensitivity);