QmlLintQuickPlugin: Warn about various SwipeDelegate issues

Implements anchor related and back/left/behind combination warnings.

Also adds a quality-of-life improvement in tst_qmllint where we print the
line when an expected message is missing.

Task-number: QTBUG-102277
Task-number: QTBUG-102859
Change-Id: I56068c75e3c6187845b079a6689debefa363a5e4
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/plugins/qmllint/quick/quicklintplugin.cpp

@@ -317,6 +317,79 @@ void AnchorsValidatorPass::run(const QQmlSA::Element &element)
     }
 }
 
+ControlsSwipeDelegateValidatorPass::ControlsSwipeDelegateValidatorPass(QQmlSA::PassManager *manager)
+    : QQmlSA::ElementPass(manager)
+{
+    m_swipeDelegate = resolveType("QtQuick.Controls", "SwipeDelegate");
+}
+
+bool ControlsSwipeDelegateValidatorPass::shouldRun(const QQmlSA::Element &element)
+{
+    return !m_swipeDelegate.isNull() && element->inherits(m_swipeDelegate);
+}
+
+void ControlsSwipeDelegateValidatorPass::run(const QQmlSA::Element &element)
+{
+    for (const auto &property : { u"background"_s, u"contentItem"_s }) {
+        auto bindings = element->ownPropertyBindings(property);
+        for (auto it = bindings.first; it != bindings.second; it++) {
+            if (!it->hasObject())
+                continue;
+            const QQmlSA::Element element = it->objectType();
+            const auto bindings = element->propertyBindings(u"anchors"_s);
+            if (bindings.isEmpty())
+                continue;
+
+            if (bindings.first().bindingType() != QQmlJSMetaPropertyBinding::GroupProperty)
+                continue;
+
+            auto anchors = bindings.first().groupType();
+            for (const auto &disallowed : { u"fill"_s, u"centerIn"_s, u"left"_s, u"right"_s }) {
+                if (anchors->hasPropertyBindings(disallowed)) {
+                    QQmlJS::SourceLocation location;
+                    auto ownBindings = anchors->ownPropertyBindings(disallowed);
+                    if (ownBindings.first != ownBindings.second) {
+                        location = ownBindings.first->sourceLocation();
+                    }
+
+                    emitWarning(
+                            u"SwipeDelegate: Cannot use horizontal anchors with %1; unable to layout the item."_s
+                                    .arg(property),
+                            location);
+                    break;
+                }
+            }
+            break;
+        }
+    }
+
+    auto swipe = element->ownPropertyBindings(u"swipe"_s);
+    if (swipe.first == swipe.second)
+        return;
+
+    if (swipe.first->bindingType() != QQmlJSMetaPropertyBinding::GroupProperty)
+        return;
+
+    auto group = swipe.first->groupType();
+
+    const auto ownDirBindings = { group->ownPropertyBindings(u"right"_s),
+                                  group->ownPropertyBindings(u"left"_s),
+                                  group->ownPropertyBindings(u"behind"_s) };
+
+    auto ownBindingIterator =
+            std::find_if(ownDirBindings.begin(), ownDirBindings.end(),
+                         [](const auto &pair) { return pair.first != pair.second; });
+
+    if (ownBindingIterator == ownDirBindings.end())
+        return;
+
+    if (group->hasPropertyBindings(u"behind"_s)
+        && (group->hasPropertyBindings(u"right"_s) || group->hasPropertyBindings(u"left"_s))) {
+        emitWarning("SwipeDelegate: Cannot set both behind and left/right properties",
+                    ownBindingIterator->first->sourceLocation());
+    }
+}
+
 void QmlLintQuickPlugin::registerPasses(QQmlSA::PassManager *manager,
                                         const QQmlSA::Element &rootElement)
 {
@@ -397,6 +470,8 @@ void QmlLintQuickPlugin::registerPasses(QQmlSA::PassManager *manager,
                                          "StackView attached property only works with Items");
         attachedPropertyType->addWarning("ToolTip", { { "QtQuick", "Item" } },
                                          "ToolTip must be attached to an Item");
+
+        manager->registerElementPass(std::make_unique<ControlsSwipeDelegateValidatorPass>(manager));
     }
 
     manager->registerElementPass(std::move(attachedPropertyType));

src/plugins/qmllint/quick/quicklintplugin.h

@@ -128,6 +128,18 @@ private:
     QQmlSA::Element m_item;
 };
 
+class ControlsSwipeDelegateValidatorPass : public QQmlSA::ElementPass
+{
+public:
+    ControlsSwipeDelegateValidatorPass(QQmlSA::PassManager *manager);
+
+    bool shouldRun(const QQmlSA::Element &element) override;
+    void run(const QQmlSA::Element &element) override;
+
+private:
+    QQmlSA::Element m_swipeDelegate;
+};
+
 QT_END_NAMESPACE
 
 #endif // QUICKLINTPLUGIN_H

tests/auto/qml/qmllint/data/pluginQuick_swipeDelegate.qml

@@ -0,0 +1,19 @@
+import QtQuick.Controls
+import QtQuick
+
+Item {
+    SwipeDelegate {
+        contentItem: Item { anchors.left: parent.left }
+        background: Item { anchors.right: parent.right }
+
+        swipe.left: Item {}
+        swipe.behind: Item {}
+    }
+    SwipeDelegate {
+        contentItem: Item { anchors.centerIn: parent }
+        background: Item { anchors.fill: parent }
+
+        swipe.right: Item {}
+        swipe.behind: Item {}
+    }
+}

tests/auto/qml/qmllint/tst_qmllint.cpp

@@ -1514,23 +1514,28 @@ void TestQmllint::searchWarnings(const QJsonArray &warnings, const QString &subs
     }
 
     const auto toDescription = [](const QJsonArray &warnings, const QString &substring,
-                                  bool must = true) {
+                                  quint32 line, quint32 column, bool must = true) {
         // Note: this actually produces a very poorly formatted multi-line
         // description, but this is how we also do it in cleanQmlCode test case,
         // so this should suffice. in any case this mainly aids the debugging
         // and CI stays (or should stay) clean.
-        return QStringLiteral("qmllint output '%1' %2 contain '%3'")
-                .arg(QString::fromUtf8(QJsonDocument(warnings).toJson(QJsonDocument::Compact)),
+        QString msg = QStringLiteral("qmllint output '%1' %2 contain '%3'")
+                              .arg(QString::fromUtf8(
+                                           QJsonDocument(warnings).toJson(QJsonDocument::Compact)),
                                    must ? u"must" : u"must NOT", substring);
+        if (line != 0 || column != 0)
+            msg += u" (%1:%2)"_s.arg(line).arg(column);
+
+        return msg;
     };
 
     if (shouldContain == StringContained) {
         if (!contains)
-            qWarning() << toDescription(warnings, substring);
+            qWarning() << toDescription(warnings, substring, line, column);
         QVERIFY(contains);
     } else {
         if (contains)
-            qWarning() << toDescription(warnings, substring, false);
+            qWarning() << toDescription(warnings, substring, line, column, false);
         QVERIFY(!contains);
     }
 }
@@ -1715,6 +1720,25 @@ void TestQmllint::quickPlugin()
                               u"LayoutDirection attached property only works with Items and Windows"_s },
                       Message { u"Layout must be attached to Item elements"_s },
                       Message { u"StackView attached property only works with Items"_s } } });
+    runTest("pluginQuick_swipeDelegate.qml",
+            Result { {
+                    Message {
+                            u"SwipeDelegate: Cannot use horizontal anchors with contentItem; unable to layout the item."_s,
+                            6, 43 },
+                    Message {
+                            u"SwipeDelegate: Cannot use horizontal anchors with background; unable to layout the item."_s,
+                            7, 43 },
+                    Message { u"SwipeDelegate: Cannot set both behind and left/right properties"_s,
+                              9, 9 },
+                    Message {
+                            u"SwipeDelegate: Cannot use horizontal anchors with contentItem; unable to layout the item."_s,
+                            13, 47 },
+                    Message {
+                            u"SwipeDelegate: Cannot use horizontal anchors with background; unable to layout the item."_s,
+                            14, 42 },
+                    Message { u"SwipeDelegate: Cannot set both behind and left/right properties"_s,
+                              16, 9 },
+            } });
 }
 #endif