Fix memory leak when using small caps font

The small caps version of a font is kept as a QFontPrivate*
which is manually reference counted, but we neglected to
actually delete it when the reference count went to 0.

[ChangeLog][Fonts] Fixed a memory leak when initializing
a small caps font.

Fixes: QTBUG-93068
Change-Id: Icc7fb7a59bf523da84d2e6fa026940a7d1230525
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>
Reviewed-by: Robert Löhning <robert.loehning@qt.io>
(cherry picked from commit 11a40defff51dae2476e0da9f2b995a3a0f3bda8)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>

1 files changed, 8 insertions, 4 deletions

diff --git a/src/gui/text/qfont.cpp b/src/gui/text/qfont.cpp
index e822854292..9ab0fa3141 100644
--- a/src/gui/text/qfont.cpp
+++ b/src/gui/text/qfont.cpp
@@ -220,8 +220,10 @@ QFontPrivate::~QFontPrivate()
     if (engineData && !engineData->ref.deref())
         delete engineData;
     engineData = nullptr;
-    if (scFont && scFont != this)
-        scFont->ref.deref();
+    if (scFont && scFont != this) {
+        if (!scFont->ref.deref())
+            delete scFont;
+    }
     scFont = nullptr;
 }
 
@@ -630,8 +632,10 @@ void QFont::detach()
         if (d->engineData && !d->engineData->ref.deref())
             delete d->engineData;
         d->engineData = nullptr;
-        if (d->scFont && d->scFont != d.data())
-            d->scFont->ref.deref();
+        if (d->scFont && d->scFont != d.data()) {
+            if (!d->scFont->ref.deref())
+                delete d->scFont;
+        }
         d->scFont = nullptr;
         return;
     }