Add clarifying comment

Signed-off-by: Florian Dupuy <[email protected]>
powsybl · Dec 4, 2024 · 1f0b295 · 1f0b295
1 parent c610f1f
commit 1f0b295
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Showing 2 changed files with 10 additions and 3 deletions.
diff --git a/iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/NodeBreakerTopologyModel.java b/iidm/iidm-impl/src/main/java/com/powsybl/iidm/network/impl/NodeBreakerTopologyModel.java
@@ -263,17 +263,20 @@ private void traverse(int n, boolean[] encountered, Predicate<SwitchImpl> termin
             if (!encountered[n]) {
                 final TIntArrayList nodes = new TIntArrayList(1);
                 nodes.add(n);
-                graph.traverse(n, TraversalType.DEPTH_FIRST, (n1, e, n2) -> {
+                Traverser traverser = (n1, e, n2) -> {
                     SwitchImpl aSwitch = graph.getEdgeObject(e);
                     if (aSwitch != null && terminate.test(aSwitch)) {
                         return TraverseResult.TERMINATE_PATH;
                     }
 
                     if (!encountered[n2]) {
+                        // We need to check this as the traverser might be called twice with the same n2 but with different edges.
+                        // Note that the "encountered" array is used and maintained inside graph::traverse method, hence we should not update it.
                         nodes.add(n2);
                     }
                     return TraverseResult.CONTINUE;
-                }, encountered);
+                };
+                graph.traverse(n, TraversalType.DEPTH_FIRST, traverser, encountered);
 
                 // check that the component is a bus
                 String busId = Identifiables.getUniqueId(NAMING_STRATEGY.getId(voltageLevel, nodes), getNetwork().getIndex()::contains);

diff --git a/math/src/main/java/com/powsybl/math/graph/UndirectedGraph.java b/math/src/main/java/com/powsybl/math/graph/UndirectedGraph.java
@@ -321,7 +321,11 @@ public interface UndirectedGraph<V, E> {
      * @param v the vertex index where the traverse has to start.
      * @param traversalType the type of traversal (breadth-first or depth-first)
      * @param traverser the {@link Traverser} instance to use to know if the traverse should continue or stop.
-     * @param verticesEncountered the list of traversed vertices.
+     * @param verticesEncountered the list of traversed vertices - a vertex is considered as traversed:
+     *                           <ul>
+     *                            <li>if it is the starting vertex</li>
+     *                            <li>if one of its edges has been traversed, with a traverser result {@link TraverseResult#CONTINUE}</li>
+     *                           </ul>
      * @return false if the whole traversing has to stop, meaning that a {@link TraverseResult#TERMINATE_TRAVERSER}
      * has been returned from the traverser, true otherwise
      */