Merge pull request #680 from jdpurcell/issue679

Windows: Fix rare argument parsing bug

src/main.cpp

@@ -1,5 +1,6 @@
 #include "mainwindow.h"
 #include "qvapplication.h"
+#include "qvwin32functions.h"
 
 #include <QCommandLineParser>
 
@@ -15,7 +16,18 @@ int main(int argc, char *argv[])
     parser.addHelpOption();
     parser.addVersionOption();
     parser.addPositionalArgument(QObject::tr("file"), QObject::tr("The file to open."));
+#if defined Q_OS_WIN && WIN32_LOADED
+    // Workaround for unicode characters getting mangled in certain cases. To support unicode arguments on
+    // Windows, QCoreApplication normally ignores argv and gets them from the Windows API instead. But this
+    // only happens if it thinks argv hasn't been modified prior to being passed into QCoreApplication's
+    // constructor. Certain characters like U+2033 (double prime) get converted differently in argv versus
+    // the value Qt is comparing with (__argv). This makes Qt incorrectly think the data was changed, and
+    // it skips fetching unicode arguments from the API.
+    // https://bugreports.qt.io/browse/QTBUG-125380
+    parser.process(QVWin32Functions::getCommandLineArgs());
+#else
     parser.process(app);
+#endif
 
     auto *window = QVApplication::newWindow();
     if (!parser.positionalArguments().isEmpty())

src/qvwin32functions.cpp

@@ -145,6 +145,22 @@ void QVWin32Functions::showOpenWithDialog(const QString &filePath, const QWindow
         qDebug() << "Failed launching open with dialog";
 }
 
+// Logic borrowed from Qt's private qWinCmdArgs function
+QStringList QVWin32Functions::getCommandLineArgs()
+{
+    const QString cmdLine = QString::fromWCharArray(GetCommandLine());
+    QStringList result;
+    int size;
+    if (wchar_t **argv = CommandLineToArgvW((const wchar_t *)cmdLine.utf16(), &size)) {
+        result.reserve(size);
+        wchar_t **argvEnd = argv + size;
+        for (wchar_t **a = argv; a < argvEnd; ++a)
+            result.append(QString::fromWCharArray(*a));
+        LocalFree(argv);
+    }
+    return result;
+}
+
 QByteArray QVWin32Functions::getIccProfileForWindow(const QWindow *window)
 {
     QByteArray result;

src/qvwin32functions.h

@@ -14,6 +14,8 @@ class QVWin32Functions
 
     static void showOpenWithDialog(const QString &filePath, const QWindow *parent);
 
+    static QStringList getCommandLineArgs();
+
     static QByteArray getIccProfileForWindow(const QWindow *window);
 };