qmllint: Warn about reads of non-constant and non-notifiable properties

The binding might not update if their value changes.

Fixes: QTBUG-112508
Change-Id: I27801d662117a89c0fdddc2aaa2f1dde21b238df
Reviewed-by: Sami Shalayel <[email protected]>

3 files changed, 45 insertions, 0 deletions

diff --git a/tests/auto/qml/qmllint/data/StalePropertyRead.qml b/tests/auto/qml/qmllint/data/StalePropertyRead.qml
new file mode 100644
index 0000000000..32b9fa6347
--- /dev/null
+++ b/tests/auto/qml/qmllint/data/StalePropertyRead.qml
@@ -0,0 +1,19 @@
+import QtQml
+import TestTypes
+
+StaleBindingPropertyRead {
+    id: o
+    property int i: 0
+    readonly property int ro: 0
+
+    // Warn
+    property int p1: o.cppStale
+    property int p2: o.cppReadonly
+
+    // No Warn
+    property int p3: o.cppConstant
+    property int p4: o.cppNotifiable
+    property int p5: o.cppConstantNotifiable
+    property int p6: o.i
+    property int p7: o.ro
+}
diff --git a/tests/auto/qml/qmllint/data/TestTypes/testtypes.qmltypes b/tests/auto/qml/qmllint/data/TestTypes/testtypes.qmltypes
index 77ad6a3cef..7aeb8f5507 100644
--- a/tests/auto/qml/qmllint/data/TestTypes/testtypes.qmltypes
+++ b/tests/auto/qml/qmllint/data/TestTypes/testtypes.qmltypes
@@ -51,6 +51,7 @@ Module {
             bindable: "rsvpBindable"
             read: "rsvp"
             write: "setRsvp"
+            notify: "rsvpChanged"
             index: 0
         }
     }
@@ -188,6 +189,7 @@ Module {
             name: "data"
             type: "QVariantMap"
             read: "data"
+            notify: "dataChanged"
             index: 0
         }
     }
@@ -198,4 +200,16 @@ Module {
         exports: ["TestTypes/Foo 1.0"]
         Method { name: "print" }
     }
+    Component {
+        file: "testtypes.h"
+        name: "StaleBindingPropertyRead"
+        accessSemantics: "reference"
+        prototype: "QObject"
+        exports: ["StaticTest/StaleBindingPropertyRead 1.0"]
+        Property { name: "cppStale"; type: "int"; index: 1 }
+        Property { name: "cppConstant"; type: "int"; isPropertyConstant: true; index: 2 }
+        Property { name: "cppNotifiable"; type: "int"; notify: "cppNotifiableChanged"; index: 3 }
+        Property { name: "cppConstantNotifiable"; type: "int"; isPropertyConstant: true; notify: "cppConstantNotifiableChanged"; index: 4 }
+        Property { name: "cppReadonly"; type: "int"; isReadonly: true; index: 5 }
+    }
 }
diff --git a/tests/auto/qml/qmllint/tst_qmllint.cpp b/tests/auto/qml/qmllint/tst_qmllint.cpp
index bb7d985d03..aade1e8f46 100644
--- a/tests/auto/qml/qmllint/tst_qmllint.cpp
+++ b/tests/auto/qml/qmllint/tst_qmllint.cpp
@@ -1324,6 +1324,18 @@ expression: \${expr} \${expr} \\\${expr} \\\${expr}`)",
             << QStringLiteral("RedundantOptionalChainingEnums.qml")
             << Result{ { { "Redundant optional chaining for enum lookup"_L1, 5, 54 },
                          { "Redundant optional chaining for enum lookup"_L1, 6, 26 } } };
+    {
+        const auto msgGen = [](const QString &name, quint32 line, quint32 col) {
+            return Message{ "Reading non-constant and non-notifiable property %1. Binding might "_L1
+                            "not update when the property changes."_L1.arg(name), line, col };
+        };
+        QTest::newRow("stalePropertyRead")
+                << QStringLiteral("StalePropertyRead.qml")
+                << Result{ { msgGen("cppStale"_L1, 10, 24), msgGen("cppReadonly"_L1, 11, 24) },
+                           { msgGen("cppConstant"_L1, 14, 24), msgGen("cppNotifiable"_L1, 15, 24),
+                             msgGen("cppConstantNotifiable"_L1, 16, 24), msgGen("i"_L1, 17, 24),
+                             msgGen("ro"_L1, 18, 24) } };
+    }
 }
 
 void TestQmllint::dirtyQmlCode()