Backport upstream patch to fix QGtk3Interface::fileIcon with GLib ≥ 2.76.

debian/changelog

@@ -2,6 +2,7 @@ qt6-base (6.6.2+dfsg-11) UNRELEASED; urgency=medium
 
   [ Dmitry Shachnev ]
   * Add a patch to use _Float16 only when SSE2 is enabled (closes: #1076986).
+  * Backport upstream patch to fix QGtk3Interface::fileIcon with GLib ≥ 2.76.
 
  -- Debian Qt/KDE Maintainers <debian-qt-kde@lists.debian.org>  Thu, 01 Aug 2024 23:45:39 +0300
 

debian/patches/fix_qgtk3interface_fileicon.patch

@@ -0,0 +1,72 @@
+Description: QGtk3Theme: fix QGtk3Interface::fileIcon
+ By failing to set the G_FILE_ATTRIBUTE_STANDARD_ICON attribute, the
+ "icon" returned by g_file_info_get_icon was always null and a
+ GLib-GIO-CRITICAL warning was output to the console (at least since glib
+ 2.76.0)[1].
+ .
+ After adding the necessary attribute, the code was crashing, because now
+ a valid icon was returned, however the icon should not be freed[2],
+ which is why I removed the "g_object_unref(icon)".
+ .
+ Now it was no longer crashing, but the size of the icons was off. It was
+ passing GTK_ICON_SIZE_BUTTON (4) to gtk_icon_theme_lookup_by_gicon where
+ a size in pixels was expected. I chose 16 because that's the pixel size
+ associated with GTK_ICON_SIZE_BUTTON[3].
+ .
+ Finally I noticed the returned icons had the wrong color. It seems that
+ a GdkPixbuf uses RGBA8888 format[4]. Adding an explicit conversion to
+ ARGB32 made the icons look correct for me.
+ .
+ [1] https://gitlab.gnome.org/GNOME/glib/-/commit/ed8e86a7d41a0900d8fa57edc64264d04cf8135b
+ [2] https://docs.gtk.org/gio/method.FileInfo.get_icon.html
+ [3] https://docs.gtk.org/gtk3/enum.IconSize.html#button
+ [4] https://docs.gtk.org/gdk-pixbuf/class.Pixbuf.html#image-data
+Origin: upstream, https://code.qt.io/cgit/qt/qtbase.git/commit/?id=277d77029d7fe8f4
+Last-Update: 2024-08-02
+
+--- a/src/plugins/platformthemes/gtk3/qgtk3interface.cpp
++++ b/src/plugins/platformthemes/gtk3/qgtk3interface.cpp
+@@ -296,8 +296,10 @@ QImage QGtk3Interface::qt_convert_gdk_pi
+     const int width = gdk_pixbuf_get_width(buf);
+     const int height = gdk_pixbuf_get_height(buf);
+     const int bpl = gdk_pixbuf_get_rowstride(buf);
+-    QImage converted(data, width, height, bpl, QImage::Format_ARGB32);
+-    return converted.copy(); // detatch to survive lifetime of buf
++    QImage converted(data, width, height, bpl, QImage::Format_RGBA8888);
++
++    // convert to more optimal format and detach to survive lifetime of buf
++    return converted.convertToFormat(QImage::Format_ARGB32_Premultiplied);
+ }
+ 
+ /*!
+@@ -666,7 +668,7 @@ QIcon QGtk3Interface::fileIcon(const QFi
+     if (!file)
+         return QIcon();
+ 
+-    GFileInfo *info = g_file_query_info (file, G_FILE_ATTRIBUTE_STANDARD_CONTENT_TYPE,
++    GFileInfo *info = g_file_query_info (file, G_FILE_ATTRIBUTE_STANDARD_ICON,
+                                          G_FILE_QUERY_INFO_NONE, nullptr, nullptr);
+     if (!info) {
+         g_object_unref(file);
+@@ -681,12 +683,11 @@ QIcon QGtk3Interface::fileIcon(const QFi
+     }
+ 
+     GtkIconTheme *theme = gtk_icon_theme_get_default();
+-    GtkIconInfo *iconInfo = gtk_icon_theme_lookup_by_gicon(theme, icon, GTK_ICON_SIZE_BUTTON,
++    GtkIconInfo *iconInfo = gtk_icon_theme_lookup_by_gicon(theme, icon, 16,
+                                                                   GTK_ICON_LOOKUP_FORCE_SIZE);
+     if (!iconInfo) {
+         g_object_unref(file);
+         g_object_unref(info);
+-        g_object_unref(icon);
+         return QIcon();
+     }
+ 
+@@ -694,7 +695,6 @@ QIcon QGtk3Interface::fileIcon(const QFi
+     QImage image = qt_convert_gdk_pixbuf(buf);
+     g_object_unref(file);
+     g_object_unref(info);
+-    g_object_unref(icon);
+     g_object_unref(buf);
+     return QIcon(QPixmap::fromImage(image));
+ }

debian/patches/series

@@ -1,3 +1,6 @@
+# fixed in 6.6.3
+fix_qgtk3interface_fileicon.patch
+# fixed in 6.7.2
 upstream_Prefer-using-the-non-suffixed-libzstd-over-static-on.patch
 upstream_Ensure-that-libzstd-targets-are-promoted-to-global-i.patch
 # fixed in 6.9.0