Fix crash when examples are in multiple categories

When items are added into multiple categories, we got into a double
delete when cleaning up, e.g. when changing the shown examples to a
different Qt version.

Sort copies into categories and delete the originals as a quickfix.
Cleaner would be if we didn't allocate them on the heap in the first
place.

Fixes: QTCREATORBUG-29197
Change-Id: I6490111aba87335b0f7189c4957ed1da8681806f
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/qtsupport/examplesparser.cpp

@@ -319,16 +319,22 @@ QList<std::pair<QString, QList<ExampleItem *>>> getCategories(const QList<Exampl
     QList<ExampleItem *> other;
     QMap<QString, QList<ExampleItem *>> categoryMap;
     if (useCategories) {
+        // Append copies of the items and delete the original ones,
+        // because items might be added to multiple categories and that needs individual items
         for (ExampleItem *item : items) {
-            const QStringList itemCategories = item->metaData.value("category");
+            const QStringList itemCategories = Utils::filteredUnique(
+                item->metaData.value("category"));
             for (const QString &category : itemCategories)
-                categoryMap[category].append(item);
+                categoryMap[category].append(new ExampleItem(*item));
             if (itemCategories.isEmpty())
-                other.append(item);
+                other.append(new ExampleItem(*item));
         }
     }
     QList<std::pair<QString, QList<ExampleItem *>>> categories;
     if (categoryMap.isEmpty()) {
+        // If we tried sorting into categories, but none were defined, we copied the items
+        // into "other", which we don't use here. Get rid of them again.
+        qDeleteAll(other);
         // The example set doesn't define categories. Consider the "highlighted" ones as "featured"
         QList<ExampleItem *> featured;
         QList<ExampleItem *> allOther;
@@ -340,6 +346,8 @@ QList<std::pair<QString, QList<ExampleItem *>>> getCategories(const QList<Exampl
         if (!allOther.isEmpty())
             categories.append({otherDisplayName, allOther});
     } else {
+        // All original items have been copied into a category or other, delete.
+        qDeleteAll(items);
         const auto end = categoryMap.constKeyValueEnd();
         for (auto it = categoryMap.constKeyValueBegin(); it != end; ++it)
             categories.append(*it);

tests/auto/examples/tst_examples.cpp

@@ -88,6 +88,7 @@ void tst_Examples::parsing_data()
     QTest::addColumn<QString>("videoLength");
     QTest::addColumn<QStringList>("platforms");
     QTest::addColumn<MetaData>("metaData");
+    QTest::addColumn<QStringList>("categories");
 
     QTest::addRow("example")
         << QByteArray(R"raw(
@@ -102,6 +103,8 @@ void tst_Examples::parsing_data()
             <fileToOpen mainFile="true">widgets/widgets/analogclock/analogclock.cpp</fileToOpen>
             <meta>
                 <entry name="category">Graphics</entry>
+                <entry name="category">Graphics</entry>
+                <entry name="category">Foobar</entry>
                 <entry name="tags">widgets</entry>
             </meta>
         </example>
@@ -120,13 +123,29 @@ void tst_Examples::parsing_data()
                          "manifest/widgets/widgets/analogclock/analogclock.cpp")}
         << FilePath::fromUserInput("manifest/widgets/widgets/analogclock/analogclock.cpp")
         << FilePaths() << Example << true << false << false << ""
-        << "" << QStringList() << MetaData({{"category", {"Graphics"}}, {"tags", {"widgets"}}});
+        << "" << QStringList()
+        << MetaData({{"category", {"Graphics", "Graphics", "Foobar"}}, {"tags", {"widgets"}}})
+        << QStringList{"Foobar", "Graphics"};
+
+    QTest::addRow("no category, highlighted")
+        << QByteArray(R"raw(
+    <examples>
+        <example name="No Category, highlighted"
+                 isHighlighted="true">
+        </example>
+    </examples>
+ )raw") << /*isExamples=*/true
+        << "No Category, highlighted" << QString() << QString() << QStringList()
+        << FilePath("manifest") << QString() << FilePaths() << FilePath() << FilePaths() << Example
+        << /*hasSourceCode=*/false << false << /*isHighlighted=*/true << ""
+        << "" << QStringList() << MetaData() << QStringList{"Featured"};
 }
 
 void tst_Examples::parsing()
 {
     QFETCH(QByteArray, data);
     QFETCH(bool, isExamples);
+    QFETCH(QStringList, categories);
     const ExampleItem expected = fetchItem();
     const expected_str<QList<ExampleItem *>> result
         = parseExamples(data,
@@ -154,7 +173,17 @@ void tst_Examples::parsing()
     QCOMPARE(item.videoLength, expected.videoLength);
     QCOMPARE(item.platforms, expected.platforms);
     QCOMPARE(item.metaData, expected.metaData);
-    qDeleteAll(*result);
+
+    const QList<std::pair<QString, QList<ExampleItem *>>> resultCategories = getCategories(*result,
+                                                                                           true);
+    QCOMPARE(resultCategories.size(), categories.size());
+    for (int i = 0; i < resultCategories.size(); ++i) {
+        QCOMPARE(resultCategories.at(i).first, categories.at(i));
+        QCOMPARE(resultCategories.at(i).second.size(), 1);
+    }
+
+    for (const auto &category : resultCategories)
+        qDeleteAll(category.second);
 }
 
 QTEST_APPLESS_MAIN(tst_Examples)