layout: remove inserted dots if placing via fails

src/drawing/drawing.rs

@@ -155,6 +155,12 @@ impl<CW: Copy, R: RulesTrait> Drawing<CW, R> {
         self.add_dot_with_infringables(weight, Some(&[]))
     }
 
+    #[debug_ensures(self.geometry_with_rtree.graph().node_count() == old(self.geometry_with_rtree.graph().node_count() - 1))]
+    #[debug_ensures(self.geometry_with_rtree.graph().edge_count() == old(self.geometry_with_rtree.graph().edge_count()))]
+    pub fn remove_fixed_dot(&mut self, dot: FixedDotIndex) {
+        self.geometry_with_rtree.remove_dot(dot.into());
+    }
+
     #[debug_ensures(self.geometry_with_rtree.graph().node_count() == old(self.geometry_with_rtree.graph().node_count() + 1))]
     #[debug_ensures(self.geometry_with_rtree.graph().edge_count() == old(self.geometry_with_rtree.graph().edge_count()))]
     pub fn add_fixed_dot_infringably(&mut self, weight: FixedDotWeight) -> FixedDotIndex {

src/layout/layout.rs

@@ -1,3 +1,4 @@
+use contracts::debug_ensures;
 use enum_dispatch::enum_dispatch;
 use geo::Point;
 use rstar::AABB;
@@ -66,16 +67,34 @@ impl<R: RulesTrait> Layout<R> {
             .insert_segbend(from, around, dot_weight, seg_weight, bend_weight, cw)
     }
 
+    #[debug_ensures(ret.is_ok() -> self.drawing.node_count() == old(self.drawing.node_count()) + weight.to_layer - weight.from_layer)]
+    #[debug_ensures(ret.is_err() -> self.drawing.node_count() == old(self.drawing.node_count()))]
     pub fn add_via(&mut self, weight: ViaWeight) -> Result<GenericIndex<ViaWeight>, Infringement> {
         let compound = self.drawing.add_compound(weight.into());
+        let mut dots = vec![];
 
         for layer in weight.from_layer..=weight.to_layer {
-            let dot = self.drawing.add_fixed_dot(FixedDotWeight {
+            match self.drawing.add_fixed_dot(FixedDotWeight {
                 circle: weight.circle,
                 layer,
                 maybe_net: weight.maybe_net,
-            })?;
+            }) {
+                Ok(dot) => {
                     self.drawing.add_to_compound(dot, compound);
+                    dots.push(dot);
+                }
+                Err(err) => {
+                    // Remove inserted dots.
+
+                    self.drawing.remove_compound(compound);
+
+                    for dot in dots.iter().rev() {
+                        self.drawing.remove_fixed_dot(*dot);
+                    }
+
+                    return Err(err);
+                }
+            }
         }
 
         Ok(GenericIndex::<ViaWeight>::new(compound.node_index()))

tests/multilayer.rs

@@ -1,12 +1,41 @@
-use topola::board::mesadata::MesadataTrait;
+use topola::{
+    autorouter::{
+        invoker::{Command, InvokerError},
+        AutorouterError,
+    },
+    board::mesadata::MesadataTrait,
+    layout::via::ViaWeight,
+    math::Circle,
+    router::EmptyRouterObserver,
+};
 
 mod common;
 
 #[test]
-fn test_prerouted_lm317_breakout() {
+fn test_unrouted_lm317_breakout() {
     let mut invoker = common::load_design_and_assert(
         "tests/multilayer/data/prerouted_lm317_breakout/unrouted_lm317_breakout.dsn",
     );
+
+    let result = invoker.execute(
+        Command::PlaceVia(ViaWeight {
+            from_layer: 0,
+            to_layer: 1,
+            circle: Circle {
+                pos: [125000.0, -84000.0].into(),
+                r: 1000.0,
+            },
+            maybe_net: Some(1234),
+        }),
+        &mut EmptyRouterObserver,
+    );
+    let result = dbg!(result);
+    assert!(matches!(
+        result,
+        Err(InvokerError::Autorouter(AutorouterError::CouldNotPlaceVia(
+            ..
+        )))
+    ));
 }
 
 #[test]

tests/single_layer.rs

@@ -54,7 +54,6 @@ fn test_tht_diode_bridge_rectifier() {
         }),
         &mut EmptyRouterObserver,
     );
-    let result = dbg!(result);
     assert!(matches!(
         result,
         Err(InvokerError::Autorouter(AutorouterError::CouldNotPlaceVia(