QDebug: add streaming operators for std::unordered_map

The stream insertion operator for QDebug is not overloaded
to handle std::unordered_map

Overload the stream insertion operator for QDebug
to handle std::unordered_map

[ChangeLog][QtCore][QDebug] Added support for std::unordered_map.

Fixes: QTBUG-130290
Change-Id: I96e82f90c310dcac4a6e4d35651fb1adb6d6293a
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qdebug.cpp

@@ -1188,6 +1188,15 @@ QDebug &QDebug::putTupleLikeImplImpl(const char *ns, const char *what,
     \c T need to support streaming into QDebug.
 */
 
+/*!
+    \fn template <typename Key, typename T, typename Hash, typename KeyEqual, typename Alloc> QDebug operator<<(QDebug debug, const std::unordered_map<Key, T, Compare, Alloc> &unordered_map)
+    \relates QDebug
+    \since 6.9
+
+ Writes the contents of \a map to \a debug. Both \c Key and
+ \c T need to support streaming into QDebug.
+*/
+
 /*!
     \fn template <class Key, class T> QDebug operator<<(QDebug debug, const QHash<Key, T> &hash)
     \relates QDebug

src/corelib/io/qdebug.h

@@ -30,6 +30,7 @@
 #include <tuple>
 #include <QtCore/q20type_traits.h>
 #include <utility>
+#include <unordered_map>
 #include <vector>
 
 #if !defined(QT_LEAN_HEADERS) || QT_LEAN_HEADERS < 1
@@ -436,6 +437,12 @@ inline QDebugIfHasDebugStream<Key, T> operator<<(QDebug debug, const std::multim
     return QtPrivate::printSequentialContainer(std::move(debug), "std::multimap", map); // yes, sequential: *it is std::pair
 }
 
+template <typename Key, typename T, typename Hash, typename KeyEqual, typename Alloc>
+inline QDebug operator<<(QDebug debug, const std::unordered_map<Key, T, Hash, KeyEqual, Alloc> &unordered_map)
+{
+    return QtPrivate::printSequentialContainer(std::move(debug), "std::unordered_map", unordered_map); // yes, sequential: *it is std::pair
+}
+
 template <class Key, class T>
 inline QDebugIfHasDebugStreamContainer<QMap<Key, T>, Key, T> operator<<(QDebug debug, const QMap<Key, T> &map)
 {

tests/auto/corelib/io/qdebug/tst_qdebug.cpp

@@ -26,6 +26,7 @@ namespace pmr = std::pmr;
 namespace pmr = std;
 #endif
 #include <tuple>
+#include <unordered_map>
 
 using namespace std::chrono;
 using namespace q20::chrono;
@@ -36,6 +37,7 @@ static_assert(QTypeTraits::has_ostream_operator_v<QDebug, QMetaType>);
 static_assert(QTypeTraits::has_ostream_operator_v<QDebug, QList<int>>);
 static_assert(QTypeTraits::has_ostream_operator_v<QDebug, QMap<int, QString>>);
 static_assert(QTypeTraits::has_ostream_operator_v<QDebug, std::tuple<int, QString, QMap<int, QString>>>);
+static_assert(QTypeTraits::has_ostream_operator_v<QDebug, std::unordered_map<int, QString>>);
 struct NonStreamable {};
 static_assert(!QTypeTraits::has_ostream_operator_v<QDebug, NonStreamable>);
 static_assert(!QTypeTraits::has_ostream_operator_v<QDebug, QList<NonStreamable>>);
@@ -84,6 +86,7 @@ private slots:
     void qDebugQLatin1String() const;
     void qDebugStdPair() const;
     void qDebugStdTuple() const;
+    void qDebugStdUnorderedMap() const;
     void qDebugStdString() const;
     void qDebugStdStringView() const;
     void qDebugStdWString() const;
@@ -770,6 +773,46 @@ void tst_QDebug::qDebugStdTuple() const
     }
 }
 
+void tst_QDebug::qDebugStdUnorderedMap() const
+{
+    QByteArray file, function;
+    int line = 0;
+    MessageHandlerSetter mhs(myMessageHandler);
+
+    {
+        QDebug d = qDebug();
+        std::unordered_map<int, QString> unorderedMap{{1, "One"}, {2, "Two"}, {3, "Three"}};
+        d.nospace().noquote() << unorderedMap;
+    }
+#ifndef QT_NO_MESSAGELOGCONTEXT
+    file = __FILE__; line = __LINE__ - 5; function = Q_FUNC_INFO;
+#endif
+    QCOMPARE(s_msgType, QtDebugMsg);
+
+    QStringList expectedValues = {"std::unordered_map","std::pair(1, One)","std::pair(2, Two)","std::pair(3, Three)"};
+    for (const QString &expextedValue : expectedValues) {
+        QVERIFY(s_msg.contains(expextedValue));
+    }
+    QCOMPARE(s_file, file);
+    QCOMPARE(s_line, line);
+    QCOMPARE(s_function, function);
+
+    {
+        qDebug() << std::unordered_map<std::string, float>{{"quarter", 0.25f}, {"half", 0.5f}};
+    }
+
+    expectedValues= {"std::unordered_map","std::pair(\"quarter\", 0.25)","std::pair(\"half\", 0.5)"};
+    for (const QString &expextedValue : expectedValues) {
+        QVERIFY(s_msg.contains(expextedValue));
+    }
+
+    {
+        qDebug()<< std::unordered_map<int, QString> {};
+    }
+
+    QCOMPARE(s_msg, "std::unordered_map()"_L1);
+}
+
 void tst_QDebug::qDebugStdString() const
 {
     QString file, function;