From b80679a90f39106052f1b53f4073e679d5077a5f Mon Sep 17 00:00:00 2001
From: Marc Mutz <marc.mutz@qt.io>
Date: Wed, 15 Jan 2025 22:57:05 +0100
Subject: [PATCH] tst_QSet: check whether remove/removeIf detach if nothing is
 removed

They do.

Task-number: QTBUG-132831
Pick-to: 6.9 6.8 6.5 6.2 5.15
Change-Id: Ia4e9de7e443d11af9675924718c551a06bc4b447
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>
---
 tests/auto/corelib/tools/qset/tst_qset.cpp | 32 ++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/tests/auto/corelib/tools/qset/tst_qset.cpp b/tests/auto/corelib/tools/qset/tst_qset.cpp
index 3ef061659dc..cea77ec16b2 100644
--- a/tests/auto/corelib/tools/qset/tst_qset.cpp
+++ b/tests/auto/corelib/tools/qset/tst_qset.cpp
@@ -32,6 +32,7 @@ private slots:
     void clear();
     void cpp17ctad();
     void remove();
+    void removeOnlyDetachesIfSomethingGetsRemoved();
     void contains();
     void containsSet();
     void begin();
@@ -392,6 +393,37 @@ void tst_QSet::remove()
     }
 }
 
+void tst_QSet::removeOnlyDetachesIfSomethingGetsRemoved()
+{
+    const QSet<int> set = {0, 1, 2, 3, 4};
+
+    auto copy = set;
+    QVERIFY(!copy.isDetached());
+
+    QVERIFY(!copy.remove(42));
+    QEXPECT_FAIL("", "QTBUG-132831", Continue);
+    QVERIFY(!copy.isDetached());
+
+    copy = set;
+    QVERIFY(!copy.isDetached());
+
+    QCOMPARE(copy.removeIf([] (auto) { return false; }), 0);
+    QEXPECT_FAIL("", "QTBUG-132831", Continue);
+    QVERIFY(!copy.isDetached());
+
+    copy = set;
+    QVERIFY(!copy.isDetached());
+
+    QVERIFY(copy.remove(4));
+    QVERIFY(copy.isDetached());
+
+    copy = set;
+    QVERIFY(!copy.isDetached());
+
+    QCOMPARE(copy.removeIf([] (int e) { return e == 3; }), 1);
+    QVERIFY(copy.isDetached());
+}
+
 void tst_QSet::contains()
 {
     QSet<QString> set1;