CBOR/JSON: fix crash when comparing strings with different lengthv6.8.36.8.3

Amends 8e5ce9cd369230256045864d6fad38dbd8bee413, which introduced the
QtPrivate::equalStrings() call. At that time, equalStrings() had already
required equal lengths (see 1560e0161af70b5cf88a70e55c0b502612d433cd),
so no excuse.

[ChangeLog][QtCore][QCborMap and QJsonObject] Fixed bug that could
result in a crash or failing to find a entry in the map/object with non-
ASCII keys.

Manual conflict resolution for 6.9:
- Port from keyView() to key(), because the former is a 6.10+ feature.

Fixes: QTBUG-133744
Change-Id: I6b0f8b0a2e47d3ef905afffda6c4c079814a0914
Reviewed-by: Marc Mutz <[email protected]>
(cherry picked from commit 54daec43a041cb69cff31cbfd1dd0b7127e8ba87)
(cherry picked from commit 8e94b67ba11fecfee134950eaae5c5b29812e82c)
Reviewed-by: Qt Cherry-pick Bot <[email protected]>
(cherry picked from commit d4a90a3f3013eae4e837fbd2df63d5803f19608a)

3 files changed, 61 insertions, 2 deletions

diff --git a/src/corelib/serialization/qcborvalue_p.h b/src/corelib/serialization/qcborvalue_p.h
index 33eb912a6d9..8cb192eee0d 100644
--- a/src/corelib/serialization/qcborvalue_p.h
+++ b/src/corelib/serialization/qcborvalue_p.h
@@ -362,8 +362,8 @@ public:
 
         if (e.flags & QtCbor::Element::StringIsUtf16) {
             if (mode == QtCbor::Comparison::ForEquality)
-                return QtPrivate::equalStrings(b->asStringView(), s) ? 0 : 1;
-            return QtPrivate::compareStrings(b->asStringView(), s);
+                return b->asStringView() == s ? 0 : 1;
+            return b->asStringView().compare(s);
         }
         return compareUtf8(b, s);
     }
diff --git a/tests/auto/corelib/serialization/json/tst_qtjson.cpp b/tests/auto/corelib/serialization/json/tst_qtjson.cpp
index e6c8f90e8f9..96060bbd132 100644
--- a/tests/auto/corelib/serialization/json/tst_qtjson.cpp
+++ b/tests/auto/corelib/serialization/json/tst_qtjson.cpp
@@ -41,6 +41,7 @@ private Q_SLOTS:
     void testObjectTakeDetach();
     void testObjectSmallKeys();
     void testObjectInsertCopies();
+    void testObjectInsertNonAscii();
     void testArraySimple();
     void testArrayInsertCopies();
     void testValueObject();
@@ -714,6 +715,22 @@ void tst_QtJson::testObjectInsertCopies()
     }
 }
 
+void tst_QtJson::testObjectInsertNonAscii()
+{
+    {
+        QJsonObject myObject;
+        myObject.insert("k♭", "First key");
+        myObject.insert("a", "Second key");
+        QCOMPARE(myObject.begin().key(), "a");
+    }
+    {
+        QJsonObject myObject;
+        myObject.insert("a", "Second key");
+        myObject.insert("k♭", "First key");
+        QCOMPARE(myObject.begin().key(), "a");
+    }
+}
+
 void tst_QtJson::testArraySimple()
 {
     QJsonArray array;
diff --git a/tests/auto/corelib/serialization/qcborvalue/tst_qcborvalue.cpp b/tests/auto/corelib/serialization/qcborvalue/tst_qcborvalue.cpp
index 55ef4700950..1bd786ca04d 100644
--- a/tests/auto/corelib/serialization/qcborvalue/tst_qcborvalue.cpp
+++ b/tests/auto/corelib/serialization/qcborvalue/tst_qcborvalue.cpp
@@ -74,6 +74,7 @@ private slots:
     void mapMutateWithCopies();
     void mapStringValues();
     void mapStringKeys();
+    void mapStringKeysNonAscii();
     void mapValueRef_data() { basics_data(); }
     void mapValueRef();
     void mapInsertRemove_data() { basics_data(); }
@@ -1529,6 +1530,47 @@ void tst_QCborValue::mapStringKeys()
     QVERIFY(m2.value(QCborValue(QByteArray("foo"))).isUndefined());
     QVERIFY(m.value(QCborValue(QLatin1String("foo"))).isUndefined());
     QCOMPARE(m.value(QCborValue(QByteArray("foo"))).toString(), "bar");
+
+    m.insert(u"World"_s, QCborValue(3));    // replaces
+    QCOMPARE(m.size(), 3);
+    QCOMPARE(m.value(u"World"_s), QCborValue(3));
+    QCOMPARE(m.value("World"_L1), QCborValue(3));
+
+    m.insert(u"Hello"_s, QCborValue(4));    // replaces (must match Latin1)
+    QCOMPARE(m.size(), 3);
+    QCOMPARE(m.value(u"Hello"_s), QCborValue(4));
+    QCOMPARE(m.value("Hello"_L1), QCborValue(4));
+}
+
+void tst_QCborValue::mapStringKeysNonAscii()
+{
+    {
+        QCborMap m;
+        m["a"_L1] = 1;          // US-ASCII: 1 UTF-8 & UTF-16 code unit
+        m["\xE9"_L1] = 2;       // Latin-1: 2 UTF-8 code units, 1 UTF-16
+        m[u"ü"_s] = 3;          // ditto, but inserted as UTF-16
+        m[u"♭"_s] = 4;          // BMP over U+07FF: 3 UTF-8 code units, 1 UTF-16
+        m[u"\U00010000"_s] = 5; // non-BMP: 4 UTF-8 code units, 2 UTF-16
+
+        QCOMPARE(m.size(), 5);
+        QCOMPARE(m.value(u"a"_s), 1);
+        QCOMPARE(m.value(u"é"_s), 2);
+        QCOMPARE(m.value("\xFC"_L1), 3);
+
+        QCOMPARE(m.value(u"k♭"_s), QCborValue());
+        QCOMPARE(m.value("foo"_L1), QCborValue());
+    }
+    {
+        QCborMap m;
+        m[u"k♭"_s] = 1;
+        m[u"a"_s] = 2;
+        m[u"\U00010000"_s] = 3;
+
+        QCOMPARE(m.size(), 3);
+        QCOMPARE(m.value(u"b"_s), QCborValue());
+        QCOMPARE(m.value(u"♭"_s), QCborValue());
+        QCOMPARE(m.value("foo"_L1), QCborValue());
+    }
 }
 
 void tst_QCborValue::mapInsertRemove()