Fix editing maps that have public transit. #372

Back in #819, I broke things by creating the sidewalk+transit graph
before transit routes had been set up. This causes immediate crashing
when editing the 2 maps with transit (Arboretum and SF).

data/MANIFEST.json

@@ -4856,19 +4856,19 @@
       "compressed_size_bytes": 5791660
     },
     "data/system/us/san_francisco/maps/downtown.bin": {
-      "checksum": "795db5b07597936c2f3616164a8b23a2",
-      "uncompressed_size_bytes": 49950221,
-      "compressed_size_bytes": 19950106
+      "checksum": "d40e9b3669999d224d59511541e4f17c",
+      "uncompressed_size_bytes": 50025645,
+      "compressed_size_bytes": 19993123
     },
     "data/system/us/seattle/city.bin": {
       "checksum": "5205f53fd0402a7e39bbcda758d7ef97",
       "uncompressed_size_bytes": 326004,
       "compressed_size_bytes": 169671
     },
     "data/system/us/seattle/maps/arboretum.bin": {
-      "checksum": "38fd5c4ddcb80f77e73406322a917b63",
-      "uncompressed_size_bytes": 5764659,
-      "compressed_size_bytes": 2239895
+      "checksum": "9769f87611ebb40122e6df672908073a",
+      "uncompressed_size_bytes": 5769223,
+      "compressed_size_bytes": 2241972
     },
     "data/system/us/seattle/maps/central_seattle.bin": {
       "checksum": "e430bfe2084db852ad450f9f859cab57",

map_model/src/make/mod.rs

@@ -291,10 +291,15 @@ impl Map {
         } else {
             CreateEngine::CH
         };
-        map.pathfinder = Pathfinder::new(&map, map.routing_params().clone(), engine, timer);
+        map.pathfinder = Pathfinder::new(&map, map.routing_params().clone(), &engine, timer);
         timer.stop("setup pathfinding");
 
         transit::finalize_transit(&mut map, &raw, timer);
+        timer.start("setup pathfinding for people using transit");
+        let mut pathfinder = std::mem::replace(&mut map.pathfinder, Pathfinder::empty());
+        pathfinder.finalize_transit(&map, &engine);
+        map.pathfinder = pathfinder;
+        timer.stop("setup pathfinding for people using transit");
 
         map
     }

map_model/src/pathfind/pathfinder.rs

@@ -82,17 +82,17 @@ impl Pathfinder {
     pub fn new(
         map: &Map,
         params: RoutingParams,
-        engine: CreateEngine,
+        engine: &CreateEngine,
         timer: &mut Timer,
     ) -> Pathfinder {
         timer.start("prepare pathfinding for cars");
-        let car_graph = VehiclePathfinder::new(map, PathConstraints::Car, &params, &engine);
+        let car_graph = VehiclePathfinder::new(map, PathConstraints::Car, &params, engine);
         timer.stop("prepare pathfinding for cars");
 
         // The edge weights for bikes are so different from the driving graph that reusing the node
         // ordering actually hurts!
         timer.start("prepare pathfinding for bikes");
-        let bike_graph = VehiclePathfinder::new(map, PathConstraints::Bike, &params, &engine);
+        let bike_graph = VehiclePathfinder::new(map, PathConstraints::Bike, &params, engine);
         timer.stop("prepare pathfinding for bikes");
 
         timer.start("prepare pathfinding for buses");
@@ -116,13 +116,11 @@ impl Pathfinder {
         timer.stop("prepare pathfinding for trains");
 
         timer.start("prepare pathfinding for pedestrians");
-        let walking_graph = SidewalkPathfinder::new(map, None, &engine);
+        let walking_graph = SidewalkPathfinder::new(map, None, engine);
         timer.stop("prepare pathfinding for pedestrians");
 
-        timer.start("prepare pathfinding for pedestrians using transit");
-        let walking_with_transit_graph =
-            SidewalkPathfinder::new(map, Some((&bus_graph, &train_graph)), &engine);
-        timer.stop("prepare pathfinding for pedestrians using transit");
+        // Transit routes haven't been created yet, so defer this step
+        let walking_with_transit_graph = SidewalkPathfinder::empty();
 
         Pathfinder {
             car_graph,
@@ -171,6 +169,11 @@ impl Pathfinder {
         p
     }
 
+    pub fn finalize_transit(&mut self, map: &Map, engine: &CreateEngine) {
+        self.walking_with_transit_graph =
+            SidewalkPathfinder::new(map, Some((&self.bus_graph, &self.train_graph)), engine);
+    }
+
     /// Finds a path from a start to an end for a certain type of agent.
     pub fn pathfind(&self, req: PathRequest, map: &Map) -> Option<PathV2> {
         self.pathfind_with_params(req, map.routing_params(), PathfinderCaching::NoCache, map)