when previewing traffic signals after deleting phases, need to possibly

reset the phase counter to fix #179

docs/dev.md

@@ -139,46 +139,3 @@ Common utilities:
 - `abstutil`: a grab-bag of IO helpers, timing and logging utilities, etc
 - `geom`: types for GPS and map-space points, lines, angles, polylines,
   polygons, circles, durations, speeds
-
-## Example guide for implementing a new feature
-
-A/B Street's transit modeling only includes buses as of September 2019. If you
-wanted to start modeling light rail, you'd have to touch many layers of the
-code. This is a nice, hefty starter project to understand how everything works.
-For now, this is just an initial list of considerations -- I haven't designed or
-implemented this yet.
-
-Poking around the .osm extracts in `data/input/seattle/osm/`, you'll see a
-promising relation with `route = light_rail`. The relation points to individual
-points (nodes) as stops, and segments of the track (ways). These need to be
-represented in the initial version of the map, `RawMap`, and the final version,
-`Map`. Stations probably coincide with existing buildings, and tracks could
-probably be modeled as a special type of road. To remember the order of stations
-and group everything, there's already a notion of bus route from the `gtfs`
-crate that probably works. The `convert_osm` crate is the place to extract this
-new data from OSM. It might be worth thinking about how the light rail line gets
-clipped, since most maps won't include all of the stations -- should those maps
-just terminate trains at the stations, or should trains go to and from the map
-border?
-
-Then there are some rendering questions. How should special buildings that act
-as light rail stations be displayed? What about the track between stations, and
-how to draw trains moving on the track? The track is sometimes underground,
-sometimes at-grade with the road (like near Colombia City -- there it even has
-to somehow be a part of the existing intersections!), and sometimes over the
-road. How to draw it without being really visually noisy with existing stuff on
-the ground? Should trains between stations even be drawn at all, or should
-hovering over stations show some kind of ETA?
-
-For modeling the movement of the trains along the track, I'd actually recommend
-using the existing driving model. Tracks can be a new `LaneType` (that gets
-rendered as nice train tracks, probably), and trains can be a new `VehicleType`.
-This way, trains queueing happens for free. There's even existing logic to make
-buses wait at bus stops and load passengers; maybe that should be extended to
-load passengers from a building? How should passengers walking to the platform
-be modeled and rendered -- it takes a few minutes sometimes!
-
-Finally, you'll need to figure out how to make some trips incorporate light
-rail. Pedestrian trips have the option to use transit or not -- if light rail is
-modeled properly, it hopefully fits into the existing transit pathfinding and
-everything, so it'll just naturally happen.

game/src/edit/traffic_signals.rs

@@ -771,6 +771,9 @@ fn make_previewer(i: IntersectionID, phase: usize) -> Box<dyn State> {
             }
             x if x == right_now => {
                 app.primary.sim = app.suspended_sim.as_ref().unwrap().clone();
+                app.primary
+                    .sim
+                    .handle_live_edited_traffic_signals(&app.primary.map);
             }
             _ => unreachable!(),
         };