From a8bcf68a5ec91b4ca4209c36310def145c8afe97 Mon Sep 17 00:00:00 2001
From: Ivan Solovev <ivan.solovev@qt.io>
Date: Wed, 7 Jul 2021 14:22:13 +0200
Subject: [PATCH] Fix QMultiHash::keys(const T&) overload

The method was never tested, but it failed to compile after
QMultiHash was introduced as a separate class in 6.0.
This patch fixes it and adds some unit-tests to cover the case.

Task-number: QTBUG-91736
Pick-to: 6.2 6.1
Change-Id: I5dd989d4775efc6a9bb13c5ed1d892e499d95dc2
Reviewed-by: Lars Knoll <lars.knoll@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
---
 src/corelib/tools/qhash.h                    |  2 +-
 tests/auto/corelib/tools/qhash/tst_qhash.cpp | 65 +++++++++++++++++---
 2 files changed, 58 insertions(+), 9 deletions(-)

diff --git a/src/corelib/tools/qhash.h b/src/corelib/tools/qhash.h
index 6866dfebf3..b030fd2a93 100644
--- a/src/corelib/tools/qhash.h
+++ b/src/corelib/tools/qhash.h
@@ -1458,7 +1458,7 @@ public:
         QList<Key> res;
         const_iterator i = begin();
         while (i != end()) {
-            if (i.value()->contains(value))
+            if (i.value() == value)
                 res.append(i.key());
             ++i;
         }
diff --git a/tests/auto/corelib/tools/qhash/tst_qhash.cpp b/tests/auto/corelib/tools/qhash/tst_qhash.cpp
index 375f9048c0..cd25f417d9 100644
--- a/tests/auto/corelib/tools/qhash/tst_qhash.cpp
+++ b/tests/auto/corelib/tools/qhash/tst_qhash.cpp
@@ -44,6 +44,7 @@ private slots:
     void erase();
     void erase_edge_case();
     void key();
+    void keys();
 
     void swap();
     void count(); // copied from tst_QMap
@@ -620,6 +621,62 @@ void tst_QHash::key()
         QCOMPARE(hash2.key("zero"), 0);
         QCOMPARE(hash2.key("zero", def), 0);
     }
+
+    {
+        const int def = -1;
+        QMultiHash<int, QString> hash;
+        QCOMPARE(hash.key("val"), 0);
+        QCOMPARE(hash.key("val", def), def);
+        QVERIFY(!hash.isDetached());
+
+        hash.insert(1, "value1");
+        hash.insert(1, "value2");
+        hash.insert(2, "value1");
+
+        QCOMPARE(hash.key("value2"), 1);
+        const auto key = hash.key("value1");
+        QVERIFY(key == 1 || key == 2);
+        QCOMPARE(hash.key("value"), 0);
+        QCOMPARE(hash.key("value", def), def);
+    }
+}
+
+template <typename T>
+QList<T> sorted(const QList<T> &list)
+{
+    QList<T> res = list;
+    std::sort(res.begin(), res.end());
+    return res;
+}
+
+void tst_QHash::keys()
+{
+    {
+        QHash<QString, int> hash;
+        QVERIFY(hash.keys().isEmpty());
+        QVERIFY(hash.keys(1).isEmpty());
+        QVERIFY(!hash.isDetached());
+
+        hash.insert("key1", 1);
+        hash.insert("key2", 2);
+        hash.insert("key3", 1);
+
+        QCOMPARE(sorted(hash.keys()), QStringList({ "key1", "key2", "key3" }));
+        QCOMPARE(sorted(hash.keys(1)), QStringList({ "key1", "key3" }));
+    }
+    {
+        QMultiHash<QString, int> hash;
+        QVERIFY(hash.keys().isEmpty());
+        QVERIFY(hash.keys(1).isEmpty());
+        QVERIFY(!hash.isDetached());
+
+        hash.insert("key1", 1);
+        hash.insert("key2", 1);
+        hash.insert("key1", 2);
+
+        QCOMPARE(sorted(hash.keys()), QStringList({ "key1", "key1", "key2" }));
+        QCOMPARE(sorted(hash.keys(1)), QStringList({ "key1", "key2" }));
+    }
 }
 
 void tst_QHash::swap()
@@ -1484,14 +1541,6 @@ void tst_QHash::qmultihash_qhash_rvalue_ref_unite()
     }
 }
 
-template <typename T>
-QList<T> sorted(const QList<T> &list)
-{
-    QList<T> res = list;
-    std::sort(res.begin(), res.end());
-    return res;
-}
-
 void tst_QHash::keys_values_uniqueKeys()
 {
     QMultiHash<QString, int> hash;