qmllint: warn about duplicate property bindings

Warn about duplicate property bindings for object and script bindings.
Remove a TODO about doing this task that seemed to be at the wrong
place.

Fixes: QTBUG-118102
Change-Id: I46696b696f6c7e0c83e36077998d6118b14498ad
Reviewed-by: Olivier De Cannière <[email protected]>

2 files changed, 75 insertions, 3 deletions

diff --git a/src/qmlcompiler/qqmljsimportvisitor.cpp b/src/qmlcompiler/qqmljsimportvisitor.cpp
index 70555ef4a4..72dac04ccd 100644
--- a/src/qmlcompiler/qqmljsimportvisitor.cpp
+++ b/src/qmlcompiler/qqmljsimportvisitor.cpp
@@ -600,6 +600,9 @@ QVector<QQmlJSAnnotation> QQmlJSImportVisitor::parseAnnotations(QQmlJS::AST::UiA
 
 void QQmlJSImportVisitor::setAllBindings()
 {
+    using Key = std::pair<QQmlJSScope::ConstPtr, QString>;
+    QHash<Key, QQmlJS::SourceLocation> m_foundBindings;
+
     for (auto it = m_bindings.cbegin(); it != m_bindings.cend(); ++it) {
         // ensure the scope is resolved. If not, produce a warning.
         const QQmlJSScope::Ptr type = it->owner;
@@ -607,8 +610,32 @@ void QQmlJSImportVisitor::setAllBindings()
             continue;
 
         auto binding = it->create();
-        if (binding.isValid())
-            type->addOwnPropertyBinding(binding, it->specifier);
+        if (!binding.isValid())
+            continue;
+        type->addOwnPropertyBinding(binding, it->specifier);
+
+        // we already warn about duplicate interceptors in processPropertyBindingObjects()
+        if (binding.hasInterceptor())
+            continue;
+        const QString propertyName = binding.propertyName();
+
+        // list can be bound multiple times
+        if (type->property(propertyName).isList())
+            continue;
+
+        const Key key = std::make_pair(type, propertyName);
+        auto sourceLocationIt = m_foundBindings.constFind(key);
+        if (sourceLocationIt == m_foundBindings.constEnd()) {
+            m_foundBindings.insert(key, binding.sourceLocation());
+            continue;
+        }
+
+        const QQmlJS::SourceLocation location = binding.sourceLocation();
+        m_logger->log("Duplicate binding on property '%1'"_L1.arg(propertyName),
+                      qmlDuplicatePropertyBinding, location);
+        m_logger->log("Note: previous binding on '%1' here"_L1.arg(propertyName),
+                      qmlDuplicatePropertyBinding, *sourceLocationIt, true, true, {}, {},
+                      location.startLine);
     }
 }
 
@@ -883,7 +910,6 @@ void QQmlJSImportVisitor::processPropertyBindingObjects()
                               qmlIncompatibleType, objectBinding.location);
             }
         } else {
-            // TODO: Warn here if binding.hasValue() is true
             if (foundValueSources.contains(uniqueBindingId)) {
                 m_logger->log(
                         QStringLiteral("Cannot combine value source and binding on property \"%1\"")
diff --git a/tests/auto/qml/qmllint/tst_qmllint.cpp b/tests/auto/qml/qmllint/tst_qmllint.cpp
index 0f9c3e0a32..bb7d985d03 100644
--- a/tests/auto/qml/qmllint/tst_qmllint.cpp
+++ b/tests/auto/qml/qmllint/tst_qmllint.cpp
@@ -1401,6 +1401,48 @@ void TestQmllint::dirtyQmlSnippet_data()
                                        { "Enum keys should start with an uppercase"_L1, 1, 35 } } }
                           << defaultOptions;
 
+    QTest::newRow("duplicateObjectBinding")
+            << u"property Item i; i: Item {} i: Item {}"_s
+            << Result{ { { "Duplicate binding on property 'i'"_L1, 1, 29 },
+                         { "Note: previous binding on 'i' here"_L1, 1, 18 } } }
+            << defaultOptions;
+
+    QTest::newRow("duplicateObjectBinding2")
+            << u"property Item i: Item {} i: Item {}"_s
+            << Result{ { { "Duplicate binding on property 'i'"_L1, 1, 26 },
+                         { "Note: previous binding on 'i' here"_L1, 1, 15 } } }
+            << defaultOptions;
+
+    QTest::newRow("duplicateBinding")
+            << u"property int i; i: 42; i: 43;"_s
+            << Result{ { { "Duplicate binding on property 'i'"_L1, 1, 27 },
+                         { "Note: previous binding on 'i' here"_L1, 1, 20 } } }
+            << defaultOptions;
+
+    QTest::newRow("duplicateBinding2")
+            << u"property int i: 42; i: 43;"_s
+            << Result{ { { "Duplicate binding on property 'i'"_L1, 1, 24 },
+                         { "Note: previous binding on 'i' here"_L1, 1, 17 } } }
+            << defaultOptions;
+
+    QTest::newRow("duplicateGrouped")
+            << u"Text { font.pixelSize: 5; font.pixelSize: 10; }"_s
+            << Result{ { { "Duplicate binding on property 'pixelSize'"_L1, 1, 43 },
+                         { "Note: previous binding on 'pixelSize' here"_L1, 1, 24 } } }
+            << defaultOptions;
+
+    QTest::newRow("duplicateGrouped2")
+            << u"Text { font.pixelSize: 5; font { pixelSize: 10 } }"_s
+            << Result{ { { "Duplicate binding on property 'pixelSize'"_L1, 1, 45 },
+                         { "Note: previous binding on 'pixelSize' here"_L1, 1, 24 } } }
+            << defaultOptions;
+
+    QTest::newRow("duplicateGrouped3")
+            << u"Text { font { pixelSize: 5; pixelSize: 10 } }"_s
+            << Result{ { { "Duplicate binding on property 'pixelSize'"_L1, 1, 40 },
+                         { "Note: previous binding on 'pixelSize' here"_L1, 1, 26 } } }
+            << defaultOptions;
+
     QTest::newRow("color-name") << u"property color myColor: \"lbue\""_s
                                 << Result{ { { "Invalid color \"lbue\""_L1, 1, 25 } },
                                            {},
@@ -1464,6 +1506,10 @@ void TestQmllint::cleanQmlSnippet_data()
     QTest::newRow("testSnippet") << u"property int qwer: 123"_s << defaultOptions;
     QTest::newRow("enum") << u"enum Hello { World, Kitty, DlroW }"_s << defaultOptions;
 
+    QTest::newRow("duplicateList") << u"Item {} Item {}"_s << defaultOptions;
+    QTest::newRow("duplicateList2")
+            << u"property list<Item> myList; myList: Item {} myList: Item {}"_s << defaultOptions;
+
     QTest::newRow("color-name") << u"property color myColor: \"blue\""_s << defaultOptions;
     QTest::newRow("color-name2") << u"property color myColor\nmyColor: \"green\""_s
                                  << defaultOptions;