Disallow registration of types beginning with lowercase letters

Allowing types with lowercase names causes ambiguity, as can be seen in
QTBUG-43567 and the comment in IRBuilder::visit(), which explains that
"the grammar can't distinguish between two different definitions" whose
only difference is casing of the first letter.

- Prevent registration (return -1 with e.g. qmlRegisterType()) when a
  type name doesn't begin with an uppercase letter.
- Document the uppercase type name rule in more places.

Change-Id: I4e522c65990f418eaafa45a256e3cb07a3e01ba4
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>

1 files changed, 9 insertions, 0 deletions

diff --git a/src/qml/qml/qqmlmetatype.cpp b/src/qml/qml/qqmlmetatype.cpp
index 3a0d5c3daf..89f3ced2d6 100644
--- a/src/qml/qml/qqmlmetatype.cpp
+++ b/src/qml/qml/qqmlmetatype.cpp
@@ -1405,6 +1405,12 @@ QString registrationTypeString(QQmlType::RegistrationType typeType)
 bool checkRegistration(QQmlType::RegistrationType typeType, QQmlMetaTypeData *data, const char *uri, const QString &typeName, int majorVersion = -1)
 {
     if (!typeName.isEmpty()) {
+        if (typeName.at(0).isLower()) {
+            QString failure(QCoreApplication::translate("qmlRegisterType", "Invalid QML %1 name \"%2\"; type names must begin with an uppercase letter"));
+            data->typeRegistrationFailures.append(failure.arg(registrationTypeString(typeType)).arg(typeName));
+            return false;
+        }
+
         int typeNameLen = typeName.length();
         for (int ii = 0; ii < typeNameLen; ++ii) {
             if (!(typeName.at(ii).isLetterOrNumber() || typeName.at(ii) == '_')) {
@@ -1650,6 +1656,9 @@ int QQmlPrivate::qmlregister(RegistrationType type, void *data)
     else
         return -1;
 
+    if (!dtype.isValid())
+        return -1;
+
     QMutexLocker lock(metaTypeDataLock());
     QQmlMetaTypeData *typeData = metaTypeData();
     typeData->undeletableTypes.insert(dtype);