Always allow blocking a degenerate intersection. Visually inspected on

the lane-changing test map. #382

Also abandon sim.run_until_done; the only caller was the LC test, and it
uses 30s steps inappropriately anyway.

data/MANIFEST.json

@@ -393,16 +393,16 @@
       "size_bytes": 58730351
     },
     "data/system/seattle/prebaked_results/lakeslice/weekday.bin": {
-      "checksum": "939bdc606246dcd9cc0f374b999e54e2",
+      "checksum": "bd3fe2b14eeb9ed5b64687aa0272fcf7",
-      "size_bytes": 67222067
+      "size_bytes": 67221259
     },
     "data/system/seattle/prebaked_results/montlake/car vs bike contention.bin": {
       "checksum": "f8cd6330a51448feffddbacd221d809a",
       "size_bytes": 5226
     },
     "data/system/seattle/prebaked_results/montlake/weekday.bin": {
-      "checksum": "57ee0b9c39158817b796f24829f94e89",
+      "checksum": "780b7a472b57d7b37ac142876ce0dc0e",
-      "size_bytes": 8973017
+      "size_bytes": 8977070
     },
     "data/system/seattle/scenarios/ballard/weekday.bin": {
       "checksum": "b1e1b8acd43f99e889961b933d772712",

sim/src/mechanics/intersection.rs

@@ -5,8 +5,8 @@ use serde::{Deserialize, Serialize};
 use abstutil::{deserialize_btreemap, retain_btreeset, serialize_btreemap, FixedMap};
 use geom::{Duration, Time};
 use map_model::{
-    ControlStopSign, ControlTrafficSignal, IntersectionID, LaneID, Map, PhaseType, Traversable,
+    ControlStopSign, ControlTrafficSignal, Intersection, IntersectionID, LaneID, Map, PhaseType,
-    TurnID, TurnPriority, TurnType,
+    Traversable, TurnID, TurnPriority, TurnType,
 };
 
 use crate::mechanics::car::Car;
@@ -387,7 +387,7 @@ impl IntersectionSimState {
             if !queue.try_to_reserve_entry(
                 car,
                 !self.dont_block_the_box
-                    || allow_block_the_box(map.get_i(turn.parent).orig_id.0)
+                    || allow_block_the_box(map.get_i(turn.parent))
                     || inside_ut,
             ) {
                 if self.break_turn_conflict_cycles {
@@ -823,23 +823,30 @@ impl SignalState {
     }
 }
 
-// TODO Sometimes a traffic signal is surrounded by tiny lanes with almost no capacity. Workaround
+fn allow_block_the_box(i: &Intersection) -> bool {
-// for now.
+    // Degenerate intersections are often just artifacts of how roads are split up in OSM. Allow
-fn allow_block_the_box(osm_node_id: i64) -> bool {
+    // vehicles to get stuck in them, since the only possible thing they could block is pedestrians
+    // from using the crosswalk. Those crosswalks usually don't exist in reality, so this behavior
+    // is more realistic.
+    if i.roads.len() == 2 {
+        return true;
+    }
+
+    // TODO Sometimes a traffic signal is surrounded by tiny lanes with almost no capacity.
+    // Workaround for now.
+    let id = i.orig_id.0;
     // 23rd and Madison, Madison and John, Boren and 12th, Boren and Yesler, Lake Wash and Madison,
     // Green Lake Way N and 50th, Green Lake Way and N 64th
-    osm_node_id == 53211693
+    id == 53211693
-        || osm_node_id == 53214134
+        || id == 53214134
-        || osm_node_id == 53214133
+        || id == 53214133
-        || osm_node_id == 53165712
+        || id == 53165712
-        || osm_node_id == 281487826
+        || id == 53209840
-        || osm_node_id == 53209840
+        || id == 4249361353
-        || osm_node_id == 4249361353
+        || id == 987334546
-        || osm_node_id == 987334546
+        || id == 848817336
-        || osm_node_id == 848817336
+        || id == 3393025729
-        || osm_node_id == 3393025729
+        || id == 59995197
-        || osm_node_id == 59995197
+        || id == 53077575
-        || osm_node_id == 53077575
+        || id == 2632986818
-        || osm_node_id == 2632986818
-        || osm_node_id == 4273547929
 }

sim/src/sim/mod.rs

@@ -741,70 +741,6 @@ impl Sim {
     }
 }
 
-// Helpers to run the sim
-// TODO Old and gunky
-impl Sim {
-    pub fn run_until_done<F: Fn(&mut Sim, &Map)>(
-        &mut self,
-        map: &Map,
-        callback: F,
-        // Interpreted as a relative time
-        time_limit: Option<Duration>,
-    ) {
-        let mut last_print = Instant::now();
-        let mut last_sim_time = self.time();
-
-        loop {
-            // TODO Regular printing doesn't happen if we use a time_limit :\
-            let dt = time_limit.unwrap_or_else(|| Duration::seconds(30.0));
-
-            match panic::catch_unwind(panic::AssertUnwindSafe(|| {
-                self.timed_step(map, dt, &mut None, &mut Timer::throwaway());
-            })) {
-                Ok(()) => {}
-                Err(err) => {
-                    println!(
-                        "*************************************************************************\
-                         *******"
-                    );
-                    println!("Sim broke:");
-                    self.dump_before_abort();
-                    panic::resume_unwind(err);
-                }
-            }
-
-            let dt_real = Duration::realtime_elapsed(last_print);
-            if dt_real >= Duration::seconds(1.0) {
-                let (finished, unfinished) = self.num_trips();
-                println!(
-                    "{}: {} trips finished, {} unfinished, speed = {:.2}x, {}",
-                    self.time(),
-                    prettyprint_usize(finished),
-                    prettyprint_usize(unfinished),
-                    (self.time() - last_sim_time) / dt_real,
-                    self.scheduler.describe_stats()
-                );
-                last_print = Instant::now();
-                last_sim_time = self.time();
-            }
-            callback(self, map);
-            if self.is_done() {
-                println!(
-                    "{}: speed = {:.2}x, {}",
-                    self.time(),
-                    (self.time() - last_sim_time) / dt_real,
-                    self.scheduler.describe_stats()
-                );
-                break;
-            }
-
-            if let Some(lim) = time_limit {
-                panic!("Time limit {} hit", lim);
-            }
-        }
-    }
-}
-
 // Savestating
 impl Sim {
     pub fn save_dir(&self) -> String {

tests/src/main.rs

@@ -223,11 +223,13 @@ fn test_lane_changing(map: &Map) -> Result<(), String> {
     let mut sim = sim::Sim::new(&map, opts, &mut Timer::throwaway());
     let mut rng = sim::SimFlags::for_test("test_lane_changing").make_rng();
     scenario.instantiate(&mut sim, &map, &mut rng, &mut Timer::throwaway());
-    sim.run_until_done(&map, |_, _| {}, None);
+    while !sim.is_done() {
+        sim.tiny_step(&map, &mut None);
+    }
     // This time limit was determined by watching the scenario manually. This test prevents the
     // time from regressing, which would probably indicate something breaking related to lane
     // selection.
-    let limit = Duration::minutes(8) + Duration::seconds(35.0);
+    let limit = Duration::minutes(8) + Duration::seconds(10.0);
     if sim.time() > Time::START_OF_DAY + limit {
         panic!(
             "Lane-changing scenario took {} to complete; it should be under {}",