Fix rule based label/symbol renderers reset max scale for rules to

1:100000

And improve dox

Fixes #21845

python/gui/auto_generated/qgsscalerangewidget.sip.in

@@ -68,6 +68,13 @@ The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map.
 .. seealso:: :py:func:`setMaximumScale`
 
 .. seealso:: :py:func:`setScaleRange`
+
+.. warning::
+
+   Calling setMinimumScale() places a restriction on the acceptable maximum scale for the
+   widget, and will alter any previously set maximum scale to pass this constraint. Always
+   call setMinimumScale() before setMaximumScale() when restoring a scale range in the widget, or
+   use the convenience method setScaleRange() instead.
 %End
 
     void setMaximumScale( double scale );
@@ -80,6 +87,13 @@ The scale value indicates the scale denominator, e.g. 1000.0 for a 1:1000 map.
 .. seealso:: :py:func:`setMinimumScale`
 
 .. seealso:: :py:func:`setScaleRange`
+
+.. warning::
+
+   Calling setMinimumScale() places a restriction on the acceptable maximum scale for the
+   widget, and will alter any previously set maximum scale to pass this constraint. Always
+   call setMinimumScale() before setMaximumScale() when restoring a scale range in the widget, or
+   use the convenience method setScaleRange() instead.
 %End
 
     void setScaleRange( double min, double max );

src/app/qgsrulebasedlabelingwidget.cpp

@@ -596,8 +596,8 @@ QgsLabelingRulePropsWidget::QgsLabelingRulePropsWidget( QgsRuleBasedLabeling::Ru
   {
     groupScale->setChecked( true );
     // caution: rule uses scale denom, scale widget uses true scales
-    mScaleRangeWidget->setMaximumScale( std::max( rule->maximumScale(), 0.0 ) );
-    mScaleRangeWidget->setMinimumScale( std::max( rule->minimumScale(), 0.0 ) );
+    mScaleRangeWidget->setScaleRange( std::max( rule->minimumScale(), 0.0 ),
+                                      std::max( rule->maximumScale(), 0.0 ) );
   }
   mScaleRangeWidget->setMapCanvas( mMapCanvas );
 

src/gui/qgsscalerangewidget.h

@@ -77,6 +77,11 @@ class GUI_EXPORT QgsScaleRangeWidget : public QWidget
      * \see minimumScale()
      * \see setMaximumScale()
      * \see setScaleRange()
+     *
+     * \warning Calling setMinimumScale() places a restriction on the acceptable maximum scale for the
+     * widget, and will alter any previously set maximum scale to pass this constraint. Always
+     * call setMinimumScale() before setMaximumScale() when restoring a scale range in the widget, or
+     * use the convenience method setScaleRange() instead.
      */
     void setMinimumScale( double scale );
 
@@ -86,6 +91,11 @@ class GUI_EXPORT QgsScaleRangeWidget : public QWidget
      * \see maximumScale()
      * \see setMinimumScale()
      * \see setScaleRange()
+     *
+     * \warning Calling setMinimumScale() places a restriction on the acceptable maximum scale for the
+     * widget, and will alter any previously set maximum scale to pass this constraint. Always
+     * call setMinimumScale() before setMaximumScale() when restoring a scale range in the widget, or
+     * use the convenience method setScaleRange() instead.
      */
     void setMaximumScale( double scale );
 

src/gui/symbology/qgsrulebasedrendererwidget.cpp

@@ -647,8 +647,8 @@ QgsRendererRulePropsWidget::QgsRendererRulePropsWidget( QgsRuleBasedRenderer::Ru
   if ( mRule->dependsOnScale() )
   {
     groupScale->setChecked( true );
-    mScaleRangeWidget->setMaximumScale( std::max( rule->maximumScale(), 0.0 ) );
-    mScaleRangeWidget->setMinimumScale( std::max( rule->minimumScale(), 0.0 ) );
+    mScaleRangeWidget->setScaleRange( std::max( rule->minimumScale(), 0.0 ),
+                                      std::max( rule->maximumScale(), 0.0 ) );
   }
   mScaleRangeWidget->setMapCanvas( mContext.mapCanvas() );