From 5b3fd5e9d217a1ed7581e1e08bec2ab9641e7bcd Mon Sep 17 00:00:00 2001
From: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@qt.io>
Date: Mon, 18 Mar 2024 07:57:40 +0100
Subject: [PATCH] Revert "Don't do font merging for PUA characters"
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This reverts commit fc33fea999365c36ed446eee0db0d59d94be306b.

The change caused issues with system-wide PUA fallbacks on
platforms where this is supported. It needs to be replaced by
an approach which still falls back, but only for fonts which
are explicitly categorized as PUA fallbacks.

Pick-to: 6.6 6.5
Task-number: QTBUG-110502
Change-Id: I985a1f8076645593c50e81759872b4227d0fcd0d
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>
(cherry picked from commit 4913511d3bf8ec7838f80fbfe92c0fe900b2f003)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
---
 src/gui/text/qfontengine.cpp                  |  3 +-
 .../tst_qtextscriptengine.cpp                 | 39 -------------------
 2 files changed, 1 insertion(+), 41 deletions(-)

diff --git a/src/gui/text/qfontengine.cpp b/src/gui/text/qfontengine.cpp
index 13bb2fee8c0..dff400c18bc 100644
--- a/src/gui/text/qfontengine.cpp
+++ b/src/gui/text/qfontengine.cpp
@@ -1866,8 +1866,7 @@ bool QFontEngineMulti::stringToCMap(const QChar *str, int len,
                 && ucs4 != QChar::LineFeed
                 && ucs4 != QChar::CarriageReturn
                 && ucs4 != QChar::ParagraphSeparator
-                && QChar::category(ucs4) != QChar::Other_Control
-                && QChar::category(ucs4) != QChar::Other_PrivateUse) {
+                && QChar::category(ucs4) != QChar::Other_Control) {
             if (!m_fallbackFamiliesQueried)
                 const_cast<QFontEngineMulti *>(this)->ensureFallbackFamiliesQueried();
             for (int x = 1, n = qMin(m_engines.size(), 256); x < n; ++x) {
diff --git a/tests/auto/gui/text/qtextscriptengine/tst_qtextscriptengine.cpp b/tests/auto/gui/text/qtextscriptengine/tst_qtextscriptengine.cpp
index 71ae9f1c569..975658005e6 100644
--- a/tests/auto/gui/text/qtextscriptengine/tst_qtextscriptengine.cpp
+++ b/tests/auto/gui/text/qtextscriptengine/tst_qtextscriptengine.cpp
@@ -56,9 +56,6 @@ private slots:
 
     void shapingDisabledDevanagari();
     void shapingDisabledLatin();
-
-    void privateUseArea();
-
 private:
     bool haveTestFonts;
 };
@@ -1316,41 +1313,5 @@ void tst_QTextScriptEngine::shapingDisabledDevanagari()
     QCOMPARE(noShapingRuns.first().glyphIndexes().size(), normalRuns.first().glyphIndexes().size());
 }
 
-void tst_QTextScriptEngine::privateUseArea()
-{
-    QString privateUseAreaString = QString::fromUtf8("");
-
-    QFont font;
-    QList<QGlyphRun> withFontMerging;
-    {
-        QTextLayout layout;
-        layout.setText(privateUseAreaString);
-        layout.setFont(font);
-        layout.beginLayout();
-        layout.createLine();
-        layout.endLayout();
-
-        withFontMerging = layout.glyphRuns();
-    }
-
-    font.setStyleStrategy(QFont::NoFontMerging);
-    QList<QGlyphRun> withoutFontMerging;
-    {
-        QTextLayout layout;
-        layout.setText(privateUseAreaString);
-        layout.setFont(font);
-        layout.beginLayout();
-        layout.createLine();
-        layout.endLayout();
-
-        withoutFontMerging = layout.glyphRuns();
-    }
-
-    QCOMPARE(withFontMerging.size(), withoutFontMerging.size());
-
-    for (int i = 0; i < withFontMerging.size(); ++i)
-        QCOMPARE(withFontMerging.at(i).glyphIndexes(), withoutFontMerging.at(i).glyphIndexes());
-}
-
 QTEST_MAIN(tst_QTextScriptEngine)
 #include "tst_qtextscriptengine.moc"