Fix selection of custom list location not being retained

Author: Jon Petersson

ios/MullvadVPN/View controllers/SelectLocation/CustomListsDataSource.swift

@@ -85,18 +85,21 @@ class CustomListsDataSource: LocationDataSourceProtocol {
         return switch location {
         case let .country(countryCode):
             rootNode
-                .countryFor(code: countryCode)?.copy(withParent: parentNode)
+                .countryFor(code: countryCode)?
+                .copy(withParent: parentNode)
 
         case let .city(countryCode, cityCode):
             rootNode
-                .countryFor(code: countryCode)?.copy(withParent: parentNode)
-                .cityFor(codes: [countryCode, cityCode])
+                .countryFor(code: countryCode)?
+                .cityFor(codes: [countryCode, cityCode])?
+                .copy(withParent: parentNode)
 
         case let .hostname(countryCode, cityCode, hostCode):
             rootNode
-                .countryFor(code: countryCode)?.copy(withParent: parentNode)
+                .countryFor(code: countryCode)?
                 .cityFor(codes: [countryCode, cityCode])?
-                .hostFor(code: hostCode)
+                .hostFor(code: hostCode)?
+                .copy(withParent: parentNode)
         }
     }
 }

ios/MullvadVPN/View controllers/SelectLocation/LocationNode.swift

@@ -80,6 +80,8 @@ extension LocationNode {
 }
 
 extension LocationNode {
+    /// Recursively copies a node, its parent and its descendants from another
+    /// node (tree), with an optional custom root parent.
     func copy(withParent parent: LocationNode? = nil) -> LocationNode {
         let node = LocationNode(
             name: name,