QUrlQuery: fix operator== for emptied object case

If an object had elements and then was emptied, it will have a non-null
d pointer, which wasn't taken into account in the comparison.

Fixes: QTBUG-109840
Pick-to: 6.5 6.4 6.2
Change-Id: I69ecc04064514f939896fffd17376aa18184653c
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>

1 files changed, 6 insertions, 0 deletions

diff --git a/tests/auto/corelib/io/qurlquery/tst_qurlquery.cpp b/tests/auto/corelib/io/qurlquery/tst_qurlquery.cpp
index 1774938096..41482f4256 100644
--- a/tests/auto/corelib/io/qurlquery/tst_qurlquery.cpp
+++ b/tests/auto/corelib/io/qurlquery/tst_qurlquery.cpp
@@ -210,12 +210,14 @@ void tst_QUrlQuery::constructing()
 void tst_QUrlQuery::addRemove()
 {
     QUrlQuery query;
+    QCOMPARE(query, query);
 
     {
         // one item
         query.addQueryItem("a", "b");
         QVERIFY(!query.isEmpty());
         QVERIFY(query.hasQueryItem("a"));
+        QCOMPARE_NE(query, QUrlQuery());
         QCOMPARE(query.queryItemValue("a"), QString("b"));
         QCOMPARE(query.allQueryItemValues("a"), QStringList() << "b");
 
@@ -226,6 +228,7 @@ void tst_QUrlQuery::addRemove()
     }
 
     QUrlQuery original = query;
+    QCOMPARE(query, original);
 
     {
         // two items
@@ -298,6 +301,9 @@ void tst_QUrlQuery::addRemove()
         query.removeQueryItem("a");
         query.removeQueryItem("e");
         QVERIFY(query.isEmpty());
+        QVERIFY(query.isDetached());
+        QCOMPARE_NE(query, original);
+        QCOMPARE(query, QUrlQuery());
     }
 }