Use a custom folder icon instead of O/S folder icon

...because using O/S folder icon can causes crashes.

Fixes #18260

Author: nyalldawson

images/images.qrc

@@ -714,6 +714,8 @@
         <file>themes/default/mActionReverseLine.svg</file>
         <file>themes/default/mActionAdd3DMap.svg</file>
         <file>themes/default/mIndicatorNonRemovable.svg</file>
+        <file>themes/default/mIconFolder.svg</file>
+        <file>themes/default/mIconFolderOpen.svg</file>
     </qresource>
     <qresource prefix="/images/tips">
         <file alias="symbol_levels.png">qgis_tips/symbol_levels.png</file>

images/themes/default/mIconFolder.svg

@@ -111,11 +111,7 @@ def __init__(self, showSearch=True):
         super(ConfigDialog, self).__init__(None)
         self.setupUi(self)
 
-        self.groupIcon = QIcon()
-        self.groupIcon.addPixmap(self.style().standardPixmap(
-            QStyle.SP_DirClosedIcon, None), QIcon.Normal, QIcon.Off)
-        self.groupIcon.addPixmap(self.style().standardPixmap(
-            QStyle.SP_DirOpenIcon, None), QIcon.Normal, QIcon.On)
+        self.groupIcon = QgsApplication.getThemeIcon('mIconFolder.svg')
 
         self.model = QStandardItemModel()
         self.tree.setModel(self.model)

images/themes/default/mIconFolderOpen.svg

@@ -28,6 +28,7 @@
 import os
 import warnings
 
+from qgis.core import QgsApplication
 from qgis.gui import QgsGui
 from qgis.PyQt import uic
 from qgis.PyQt.QtCore import Qt, QCoreApplication
@@ -52,8 +53,7 @@ def __init__(self):
 
         QgsGui.instance().enableAutoGeometryRestore(self)
 
-        self.groupIcon = self.style().standardIcon(
-            QStyle.SP_DirClosedIcon)
+        self.groupIcon = QgsApplication.getThemeIcon('mIconFolder.svg')
 
         self.keyIcon = self.style().standardIcon(QStyle.SP_FileIcon)
 

python/plugins/processing/gui/ConfigDialog.py

@@ -45,6 +45,7 @@
 #include "qgsvariantdelegate.h"
 #include "qgslogger.h"
 #include "qgssettings.h"
+#include "qgsapplication.h"
 
 QgsSettingsTree::QgsSettingsTree( QWidget *parent )
   : QTreeWidget( parent )
@@ -62,10 +63,7 @@ QgsSettingsTree::QgsSettingsTree( QWidget *parent )
 
   mRefreshTimer.setInterval( 2000 );
 
-  mGroupIcon.addPixmap( style()->standardPixmap( QStyle::SP_DirClosedIcon ),
-                        QIcon::Normal, QIcon::Off );
-  mGroupIcon.addPixmap( style()->standardPixmap( QStyle::SP_DirOpenIcon ),
-                        QIcon::Normal, QIcon::On );
+  mGroupIcon = QgsApplication::getThemeIcon( QStringLiteral( "mIconFolderOpen.svg" ) );
   mKeyIcon = style()->standardIcon( QStyle::SP_FileIcon );
 
   setEditTriggers( QAbstractItemView::AllEditTriggers );

python/plugins/processing/gui/HistoryDialog.py

@@ -91,32 +91,12 @@ QIcon QgsDataCollectionItem::iconDataCollection()
 
 QIcon QgsDataCollectionItem::openDirIcon()
 {
-  static QIcon sIcon;
-
-  if ( sIcon.isNull() )
-  {
-    // initialize shared icons
-    QStyle *style = QApplication::style();
-    sIcon = QIcon( style->standardIcon( QStyle::SP_DirOpenIcon ) );
-  }
-
-  return sIcon;
+  return QgsApplication::getThemeIcon( QStringLiteral( "/mIconFolderOpen.svg" ) );
 }
 
 QIcon QgsDataCollectionItem::iconDir()
 {
-  static QIcon sIcon;
-
-  if ( sIcon.isNull() )
-  {
-    // initialize shared icons
-    QStyle *style = QApplication::style();
-    sIcon = QIcon( style->standardIcon( QStyle::SP_DirClosedIcon ) );
-    sIcon.addPixmap( style->standardPixmap( QStyle::SP_DirOpenIcon ),
-                     QIcon::Normal, QIcon::On );
-  }
-
-  return sIcon;
+  return QgsApplication::getThemeIcon( QStringLiteral( "/mIconFolder.svg" ) );
 }
 
 QIcon QgsFavoritesItem::iconFavorites()
@@ -981,7 +961,7 @@ QgsDirectoryParamWidget::QgsDirectoryParamWidget( const QString &path, QWidget *
   setHeaderLabels( labels );
 
   QStyle *style = QApplication::style();
-  QIcon iconDirectory = QIcon( style->standardIcon( QStyle::SP_DirClosedIcon ) );
+  QIcon iconDirectory = QgsApplication::getThemeIcon( QStringLiteral( "mIconFolderOpen.svg" ) );
   QIcon iconFile = QIcon( style->standardIcon( QStyle::SP_FileIcon ) );
   QIcon iconDirLink = QIcon( style->standardIcon( QStyle::SP_DirLinkIcon ) );
   QIcon iconFileLink = QIcon( style->standardIcon( QStyle::SP_FileLinkIcon ) );