Allow QQmlComponent::loadUrl() to load absolute URLs with relative paths

Currently, QQmlTypeLoader::getType() will assert if passed a relative
URL, because it needs absolute URLs in order to ensure that it can use
them as keys for its cache. After dc6b73390 was merged, URLs like
QUrl::fromLocalFile("main.qml") (which are currently used in examples
of how to load a QQmlComponent) started causing the assertion to fail.

As mentioned in the comments of the bug report, some patches have
already been applied to QQmlComponent's QString-based constructors,
but both the constructors taking a QUrl and loadUrl() itself need
fixing.

This patch puts the fix into loadUrl() (the constructors call this
function) so that every operation
involving URLs is successful when using the documented methods.

Task-number: QTBUG-58837
Change-Id: Ib54ca52eddce6e7781cf96015f4c15af604233d3
Reviewed-by: David Faure <david.faure@kdab.com>

1 files changed, 19 insertions, 13 deletions

diff --git a/src/qml/qml/qqmlcomponent.cpp b/src/qml/qml/qqmlcomponent.cpp
index e872b1d92e..4da6b7958c 100644
--- a/src/qml/qml/qqmlcomponent.cpp
+++ b/src/qml/qml/qqmlcomponent.cpp
@@ -496,8 +496,7 @@ QQmlComponent::QQmlComponent(QQmlEngine *engine, QObject *parent)
     Create a QQmlComponent from the given \a url and give it the
     specified \a parent and \a engine.
 
-    Ensure that the URL provided is full and correct, in particular, use
-    \l QUrl::fromLocalFile() when loading a file from the local filesystem.
+    \include qqmlcomponent.qdoc url-note
 
     \sa loadUrl()
 */
@@ -511,8 +510,7 @@ QQmlComponent::QQmlComponent(QQmlEngine *engine, const QUrl &url, QObject *paren
     specified \a parent and \a engine. If \a mode is \l Asynchronous,
     the component will be loaded and compiled asynchronously.
 
-    Ensure that the URL provided is full and correct, in particular, use
-    \l QUrl::fromLocalFile() when loading a file from the local filesystem.
+    \include qqmlcomponent.qdoc url-note
 
     \sa loadUrl()
 */
@@ -548,7 +546,7 @@ QQmlComponent::QQmlComponent(QQmlEngine *engine, const QString &fileName,
     : QQmlComponent(engine, parent)
 {
     Q_D(QQmlComponent);
-    const QUrl url = QDir::isAbsolutePath(fileName) ? QUrl::fromLocalFile(fileName) : d->engine->baseUrl().resolved(QUrl(fileName));
+    const QUrl url = QDir::isAbsolutePath(fileName) ? QUrl::fromLocalFile(fileName) : QUrl(fileName);
     d->loadUrl(url, mode);
 }
 
@@ -608,8 +606,7 @@ QQmlContext *QQmlComponent::creationContext() const
 /*!
     Load the QQmlComponent from the provided \a url.
 
-    Ensure that the URL provided is full and correct, in particular, use
-    \l QUrl::fromLocalFile() when loading a file from the local filesystem.
+    \include qqmlcomponent.qdoc url-note
 */
 void QQmlComponent::loadUrl(const QUrl &url)
 {
@@ -621,8 +618,7 @@ void QQmlComponent::loadUrl(const QUrl &url)
     Load the QQmlComponent from the provided \a url.
     If \a mode is \l Asynchronous, the component will be loaded and compiled asynchronously.
 
-    Ensure that the URL provided is full and correct, in particular, use
-    \l QUrl::fromLocalFile() when loading a file from the local filesystem.
+    \include qqmlcomponent.qdoc url-note
 */
 void QQmlComponent::loadUrl(const QUrl &url, QQmlComponent::CompilationMode mode)
 {
@@ -635,11 +631,21 @@ void QQmlComponentPrivate::loadUrl(const QUrl &newUrl, QQmlComponent::Compilatio
     Q_Q(QQmlComponent);
     clear();
 
-    if ((newUrl.isRelative() && !newUrl.isEmpty())
-    || newUrl.scheme() == QLatin1String("file")) // Workaround QTBUG-11929
-        url = engine->baseUrl().resolved(newUrl);
-    else
+    if (newUrl.isRelative()) {
+        // The new URL is a relative URL like QUrl("main.qml").
+        url = engine->baseUrl().resolved(QUrl(newUrl.toString()));
+    } else if (engine->baseUrl().isLocalFile() && newUrl.isLocalFile() && !QDir::isAbsolutePath(newUrl.toLocalFile())) {
+        // The new URL is a file on disk but it's a relative path; e.g.:
+        // QUrl::fromLocalFile("main.qml") or QUrl("file:main.qml")
+        // We need to remove the scheme so that it becomes a relative URL with a relative path:
+        QUrl fixedUrl(newUrl);
+        fixedUrl.setScheme(QString());
+        // Then, turn it into an absolute URL with an absolute path by resolving it against the engine's baseUrl().
+        // This is a compatibility hack for QTBUG-58837.
+        url = engine->baseUrl().resolved(fixedUrl);
+    } else {
         url = newUrl;
+    }
 
     if (newUrl.isEmpty()) {
         QQmlError error;