Make sure that we have a valid plugin before using it

The code assumed that loading the plugin would succeed if we could
read its meta-data, this is of course not always the case, as a plugin
might not have its dependencies met and fail to load, e.g., this is
the case if trying to use the QtWebEngine plugin when QtWebEngine isn't
installed.

Fixes: QTBUG-71380
Change-Id: Ib88281b2b291213891cfbb77b0728c1bdd6dd1fd
Reviewed-by: Kai Koehne <kai.koehne@qt.io>

1 files changed, 5 insertions, 2 deletions

diff --git a/src/webview/qtwebviewfunctions.cpp b/src/webview/qtwebviewfunctions.cpp
index 975bb17..01efbf6 100644
--- a/src/webview/qtwebviewfunctions.cpp
+++ b/src/webview/qtwebviewfunctions.cpp
@@ -61,9 +61,12 @@ QT_BEGIN_NAMESPACE
 void QtWebView::initialize()
 {
     if (QWebViewFactory::requiresExtraInitializationSteps()) {
+        // There might be plugins available, but their dependencies might not be met,
+        // so make sure we have a valid plugin before using it.
+        // Note: A warning will be printed later if we're unable to load the plugin.
         QWebViewPlugin *plugin = QWebViewFactory::getPlugin();
-        Q_ASSERT(plugin);
-        plugin->prepare();
+        if (plugin)
+            plugin->prepare();
     }
 }