QQmlImport: Handle file selectors in qmldir

With file selectors, a type can exist in the same version under
different paths. Detect this case, canonicalize the filename to the
selector free version, and rely on the engine to resolve a URL to the
correct file.

Pick-to: 6.5 6.4 6.2
Fixes: QTBUG-107797
Change-Id: I0f74fd37936abfa08547fb439bfa5264e6ca4787
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

src/qml/qml/qqmlimport.cpp

@@ -32,6 +32,8 @@
 #include <algorithm>
 #include <functional>
 
+using namespace Qt::Literals::StringLiterals;
+
 QT_BEGIN_NAMESPACE
 
 DEFINE_BOOL_CONFIG_OPTION(qmlImportTrace, QML_IMPORT_TRACE)
@@ -1034,6 +1036,26 @@ QString QQmlImports::resolvedUri(const QString &dir_arg, QQmlImportDatabase *dat
     return stableRelativePath;
 }
 
+/* removes all file selector occurrences in path
+   firstPlus is the position of the initial '+' in the path
+   which we always have as we check for '+' to decide whether
+   we need to do some work at all
+*/
+static QString pathWithoutFileSelectors(QString path, // we want a copy of path
+                                        qsizetype firstPlus)
+{
+    do {
+        Q_ASSERT(path.at(firstPlus) == u'+');
+        const auto eos = path.size();
+        qsizetype terminatingSlashPos = firstPlus + 1;
+        while (terminatingSlashPos != eos && path.at(terminatingSlashPos) != u'/')
+            ++terminatingSlashPos;
+        path.remove(firstPlus, terminatingSlashPos - firstPlus + 1);
+        firstPlus = path.indexOf(u'+', firstPlus);
+    } while (firstPlus != -1);
+    return path;
+}
+
 /*!
   \internal
 
@@ -1080,10 +1102,42 @@ QTypeRevision QQmlImports::matchingQmldirVersion(
     typedef QQmlDirComponents::const_iterator ConstIterator;
     const QQmlDirComponents &components = qmldir.components();
 
+    QMultiHash<QString, ConstIterator> baseFileName2ConflictingComponents;
+
     ConstIterator cend = components.constEnd();
     for (ConstIterator cit = components.constBegin(); cit != cend; ++cit) {
         for (ConstIterator cit2 = components.constBegin(); cit2 != cit; ++cit2) {
             if (cit2->typeName == cit->typeName && cit2->version == cit->version) {
+                // ugly heuristic to deal with file selectors
+                const auto comp2PotentialFileSelectorPos = cit2->fileName.indexOf(u'+');
+                const bool comp2MightHaveFileSelector = comp2PotentialFileSelectorPos != -1;
+                /* If we detect conflicting paths, we check if they agree when we remove anything looking like a
+                   file selector.
+                   We need to create copies of the filenames, otherwise QString::replace would modify the
+                   existing file-names
+                 */
+                QString compFileName1 = cit->fileName;
+                QString compFileName2 = cit2->fileName;
+                if (auto fileSelectorPos1 = compFileName1.indexOf(u'+'); fileSelectorPos1 != -1) {
+                    // existing entry was file selector entry, fix it up
+                    // it could also be the case that _both_ are using file selectors
+                    QString baseName =  comp2MightHaveFileSelector ? pathWithoutFileSelectors(compFileName2,
+                                                                                         comp2PotentialFileSelectorPos)
+                                                                   : compFileName2;
+                    if (pathWithoutFileSelectors(compFileName1, fileSelectorPos1) == baseName) {
+                        baseFileName2ConflictingComponents.insert(baseName, cit);
+                        baseFileName2ConflictingComponents.insert(baseName, cit2);
+                        continue;
+                    }
+                    // fall through to error case
+                } else if (comp2MightHaveFileSelector) {
+                    // new entry contains file selector (and we now that cit did not)
+                    if (pathWithoutFileSelectors(compFileName2, comp2PotentialFileSelectorPos) == compFileName1) {
+                        baseFileName2ConflictingComponents.insert(compFileName1, cit2);
+                        continue;
+                    }
+                    // fall through to error case
+                }
                 // This entry clashes with a predecessor
                 QQmlError error;
                 error.setDescription(QQmlImportDatabase::tr("\"%1\" version %2.%3 is defined more than once in module \"%4\"")
@@ -1097,6 +1151,14 @@ QTypeRevision QQmlImports::matchingQmldirVersion(
         addVersion(cit->version);
     }
 
+    // ensure that all components point to the actual base URL, and let the file selectors resolve them correctly during URL resolution
+    for (auto keyIt = baseFileName2ConflictingComponents.keyBegin(); keyIt != baseFileName2ConflictingComponents.keyEnd(); ++keyIt) {
+        const QString& baseFileName = *keyIt;
+        const auto conflictingComponents = baseFileName2ConflictingComponents.values(baseFileName);
+        for (ConstIterator component: conflictingComponents)
+            component->fileName = baseFileName;
+    }
+
     typedef QList<QQmlDirParser::Script>::const_iterator SConstIterator;
     const QQmlDirScripts &scripts = qmldir.scripts();
 

tests/auto/qml/qqmlfileselector/data/qmldirtest/main.qml

@@ -0,0 +1,13 @@
+import QtQuick
+import qmldirtest
+
+Window {
+    width: 640
+    height: 480
+    visible: true
+    property color color: mybutton.color
+
+    MyButton {
+        id: mybutton
+    }
+}

tests/auto/qml/qqmlfileselector/data/qmldirtest/qml/+linux/MyButton.qml

@@ -0,0 +1,7 @@
+import QtQuick
+
+Rectangle {
+    width: 300
+    height: 50
+    color: "blue"
+}

tests/auto/qml/qqmlfileselector/data/qmldirtest/qml/+macos/MyButton.qml

@@ -0,0 +1,7 @@
+import QtQuick
+
+Rectangle {
+    width: 300
+    height: 50
+    color: "yellow"
+}

tests/auto/qml/qqmlfileselector/data/qmldirtest/qml/MyButton.qml

@@ -0,0 +1,7 @@
+import QtQuick
+
+Rectangle {
+    width: 300
+    height: 50
+    color: "green"
+}

tests/auto/qml/qqmlfileselector/data/qmldirtest/qmldir

@@ -0,0 +1,5 @@
+module qmldirtest
+MyButton 1.0 qml/MyButton.qml
+MyButton 1.0 qml/+linux/MyButton.qml
+MyButton 1.0 qml/+macos/MyButton.qml
+

tests/auto/qml/qqmlfileselector/tst_qqmlfileselector.cpp

@@ -22,7 +22,7 @@ private slots:
     void basicTest();
     void basicTestCached();
     void applicationEngineTest();
-
+    void qmldirCompatibility();
 };
 
 void tst_qqmlfileselector::basicTest()
@@ -70,6 +70,23 @@ void tst_qqmlfileselector::applicationEngineTest()
     QCOMPARE(object->property("value").toString(), QString("selected"));
 }
 
+void tst_qqmlfileselector::qmldirCompatibility()
+{
+    QQmlApplicationEngine engine;
+    engine.addImportPath(dataDirectory());
+    engine.load(testFileUrl("qmldirtest/main.qml"));
+    QVERIFY(!engine.rootObjects().isEmpty());
+    QObject *object = engine.rootObjects().at(0);
+    auto color = object->property("color").value<QColor>();
+#if defined(Q_OS_LINUX) && !defined(Q_OS_ANDROID)
+    QCOMPARE(color, QColorConstants::Svg::blue);
+#elif defined(Q_OS_DARWIN)
+    QCOMPARE(color, QColorConstants::Svg::yellow);
+#else
+    QCOMPARE(color, QColorConstants::Svg::green);
+#endif
+}
+
 QTEST_MAIN(tst_qqmlfileselector)
 
 #include "tst_qqmlfileselector.moc"