Fix crash when stored scale list contains invalid values

nyalldawson · nyalldawson · commit e51297bc1770 · 2023-03-30T03:45:35.000+10:00
Can happen as a result of invalid settings being written by
QGIS 3.30.0
diff --git a/src/gui/qgsscalecombobox.cpp b/src/gui/qgsscalecombobox.cpp
@@ -55,13 +55,14 @@ void QgsScaleComboBox::updateScales( const QStringList &scales )
     }
   }
 
-  QStringList parts;
-  double denominator;
-  bool ok;
   for ( int i = 0; i < myScalesList.size(); ++i )
   {
-    parts = myScalesList[ i ] .split( ':' );
-    denominator = QLocale().toDouble( parts[1], &ok );
+    const QStringList parts = myScalesList[ i ] .split( ':' );
+    if ( parts.size() < 2 )
+      continue;
+
+    bool ok = false;
+    const double denominator = QLocale().toDouble( parts[1], &ok );
     if ( ok )
     {
       myScalesList[ i ] = toString( denominator );

Original file line number	Diff line number	Diff line change
`@@ -55,13 +55,14 @@ void QgsScaleComboBox::updateScales( const QStringList &scales )`
`55`	`55`	`}`
`56`	`56`	`}`
`57`	`57`
`58`		`- QStringList parts;`
`59`		`- double denominator;`
`60`		`- bool ok;`
`61`	`58`	`for ( int i = 0; i < myScalesList.size(); ++i )`
`62`	`59`	`{`
`63`		`- parts = myScalesList[ i ] .split( ':' );`
`64`		`- denominator = QLocale().toDouble( parts[1], &ok );`
	`60`	`+ const QStringList parts = myScalesList[ i ] .split( ':' );`
	`61`	`+ if ( parts.size() < 2 )`
	`62`	`+ continue;`
	`63`	`+`
	`64`	`+ bool ok = false;`
	`65`	`+ const double denominator = QLocale().toDouble( parts[1], &ok );`
`65`	`66`	`if ( ok )`
`66`	`67`	`{`
`67`	`68`	`myScalesList[ i ] = toString( denominator );`