QStyleSheetStyle: Don't interfere with QFontDialog

The sample lineedit in Qt's own font dialog shouldn't have its font
affected by stylesheets.
Not only does this hampers the ability to preview the font, it actually
overrides the font selection as that one is taken directly from the
widget.

Task-number: QTBUG-41513
Change-Id: I11d0bef8c7bf7bdae4cc08b6b9276d0fc14a75fb
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@theqtcompany.com>

src/widgets/dialogs/qfontdialog.cpp

@@ -322,6 +322,7 @@ void QFontDialogPrivate::init()
 
     familyList->setFocus();
     retranslateStrings();
+    sampleEdit->setObjectName(QLatin1String("qt_fontDialog_sampleEdit"));
 }
 
 /*!

src/widgets/styles/qstylesheetstyle.cpp

@@ -5828,6 +5828,10 @@ bool QStyleSheetStyle::event(QEvent *e)
 
 void QStyleSheetStyle::updateStyleSheetFont(QWidget* w) const
 {
+    // Qt's fontDialog relies on the font of the sample edit for its selection,
+    // we should never override it.
+    if (w->objectName() == QLatin1String("qt_fontDialog_sampleEdit"))
+        return;
     QWidget *container = containerWidget(w);
     QRenderRule rule = renderRule(container, PseudoElement_None,
             PseudoClass_Active | PseudoClass_Enabled | extendedPseudoClass(container));

tests/auto/gui/text/qglyphrun/qglyphrun.pro

@@ -8,14 +8,13 @@ linux: CONFIG += insignificant_test
 SOURCES += \
     tst_qglyphrun.cpp
 
-android {
+
+wince* {
+    additionalFiles.files = test.ttf
+    additionalFiles.path = ../../../shared/resources/
+    DEPLOYMENT += additionalFiles
+} else {
     RESOURCES += \
         testdata.qrc
 }
 
-wince* {
-    additionalFiles.files = test.ttf
-    additionalFiles.path = .
-    DEPLOYMENT += additionalFiles
-}
-

tests/auto/gui/text/qglyphrun/testdata.qrc

@@ -1,5 +1,5 @@
 <RCC>
     <qresource prefix="/">
-        <file>test.ttf</file>
+        <file alias="test.ttf">../../../shared/resources/test.ttf</file>
     </qresource>
 </RCC>

tests/auto/gui/text/qrawfont/qrawfont.pro

@@ -7,9 +7,5 @@ QT = core core-private gui gui-private testlib
 SOURCES += \
     tst_qrawfont.cpp
 
-TESTDATA += testfont_bold_italic.ttf  testfont.ttf
-
-android {
-    RESOURCES += \
-        testdata.qrc
-}
+RESOURCES += \
+    testdata.qrc

tests/auto/gui/text/qrawfont/testdata.qrc

@@ -1,6 +1,6 @@
 <RCC>
     <qresource prefix="/">
         <file>testfont_bold_italic.ttf</file>
-        <file>testfont.ttf</file>
+        <file alias="testfont.ttf">../../../shared/resources/testfont.ttf</file>
     </qresource>
 </RCC>

tests/auto/widgets/dialogs/qfontdialog/qfontdialog.pro

@@ -7,6 +7,8 @@ QT += core-private gui-private
 
 SOURCES  += tst_qfontdialog.cpp
 
+RESOURCES += testfonts.qrc
+
 mac {
 #    ### fixme
 #    OBJECTIVE_SOURCES += tst_qfontdialog_mac_helpers.mm

tests/auto/widgets/dialogs/qfontdialog/testfonts.qrc

@@ -0,0 +1,6 @@
+<RCC>
+    <qresource prefix="/">
+        <file alias="test.ttf">../../../shared/resources/test.ttf</file>
+        <file alias="testfont.ttf">../../../shared/resources/testfont.ttf</file>
+    </qresource>
+</RCC>

tests/auto/widgets/dialogs/qfontdialog/tst_qfontdialog.cpp

@@ -36,6 +36,7 @@
 
 
 #include <qapplication.h>
+#include <qfontdatabase.h>
 #include <qfontinfo.h>
 #include <qtimer.h>
 #include <qmainwindow.h>
@@ -70,6 +71,10 @@ private slots:
     void setFont();
     void task256466_wrongStyle();
     void setNonStandardFontSize();
+#ifndef QT_NO_STYLE_STYLESHEET
+    void qtbug_41513_stylesheetStyle();
+#endif
+
 
 private:
     void runSlotWithFailsafeTimer(const char *member);
@@ -201,6 +206,31 @@ void tst_QFontDialog::setNonStandardFontSize()
 {
     runSlotWithFailsafeTimer(SLOT(testNonStandardFontSize()));
 }
+#ifndef QT_NO_STYLE_STYLESHEET
+static const QString offendingStyleSheet = QStringLiteral("* { font-family: \"QtBidiTestFont\"; }");
+
+void tst_QFontDialog::qtbug_41513_stylesheetStyle()
+{
+    if (QFontDatabase::addApplicationFont(QFINDTESTDATA("test.ttf")) < 0)
+        QSKIP("Test fonts not found.");
+    if (QFontDatabase::addApplicationFont(QFINDTESTDATA("testfont.ttf")) < 0)
+        QSKIP("Test fonts not found.");
+    QFont testFont = QFont(QStringLiteral("QtsSpecialTestFont"));
+    qApp->setStyleSheet(offendingStyleSheet);
+    bool accepted = false;
+    QTimer::singleShot(2000, this, SLOT(postKeyReturn()));
+    QFont resultFont = QFontDialog::getFont(&accepted, testFont,
+        QApplication::activeWindow(),
+        QLatin1String("QFontDialog - Stylesheet Test"),
+        QFontDialog::DontUseNativeDialog);
+    QVERIFY(accepted);
+
+    QCOMPARE(resultFont, testFont);
+
+    // reset stylesheet
+    qApp->setStyleSheet(QString());
+}
+#endif // QT_NO_STYLE_STYLESHEET
 
 void tst_QFontDialog::testNonStandardFontSize()
 {