qmllint: Read qmldir files from resources where applicable

Otherwise we cannot reliably resolve composite singletons. Also we'd
end up with really interesting paths passed to QFile.

Change-Id: I2187fd4103914cff3f12f0780c428af8b56bf287
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>
Reviewed-by: Andrei Golubev <andrei.golubev@qt.io>

src/qmlcompiler/qqmljsimporter.cpp

@@ -450,7 +450,19 @@ bool QQmlJSImporter::importHelper(const QString &module, AvailableTypes *types,
                                     : qQmlResolveImportPaths(module, m_importPaths, version);
 
     for (auto const &modulePath : modulePaths) {
-        const QString qmldirPath = modulePath + SlashQmldir;
+        QString qmldirPath;
+        if (modulePath.startsWith(u':')) {
+            if (m_mapper) {
+                const QString resourcePath = modulePath.mid(
+                            1, modulePath.endsWith(u'/') ? modulePath.length() - 2 : -1)
+                        + SlashQmldir;
+                const auto entry = m_mapper->entry(
+                            QQmlJSResourceFileMapper::resourceFileFilter(resourcePath));
+                qmldirPath = entry.filePath;
+            }
+        } else {
+            qmldirPath = modulePath + SlashQmldir;
+        }
         const auto it = m_seenQmldirFiles.constFind(qmldirPath);
 
         if (it != m_seenQmldirFiles.constEnd()) {

tests/auto/qml/qmllint/data/T/A.qml

@@ -0,0 +1,6 @@
+pragma Singleton
+import QtQml
+
+QtObject {
+   property int a: 10
+}

tests/auto/qml/qmllint/data/T/a.qrc

@@ -0,0 +1,7 @@
+<RCC>
+    <qresource prefix="/">
+        <file>qmldir</file>
+        <file>A.qml</file>
+        <file>b.qml</file>
+    </qresource>
+</RCC>

tests/auto/qml/qmllint/data/T/b.qml

@@ -0,0 +1,6 @@
+import QtQml
+
+QtObject {
+    property int b: A.a
+    property int e: X.a
+}

tests/auto/qml/qmllint/data/T/qmldir

@@ -0,0 +1,2 @@
+module T
+singleton X 1.0 A.qml

tests/auto/qml/qmllint/tst_qmllint.cpp

@@ -302,6 +302,8 @@ void TestQmllint::resources()
                {QStringLiteral("--resource"), testFile("resource.qrc")});
     runQmllint(testFile("resource.qml"), false, {});
     runQmllint(testFile("badResource.qml"), true, {});
+    runQmllint(testFile("T/b.qml"), true,
+               {QStringLiteral("--resource"), testFile("T/a.qrc")});
 }
 
 void TestQmllint::dirtyQmlCode_data()