From 24b124e5368aa89798e5a2c971c6a47f38089867 Mon Sep 17 00:00:00 2001
From: Quincy Morgan <quincy.morgan@icloud.com>
Date: Tue, 16 Jun 2020 10:24:42 -0400
Subject: [PATCH] Fix infinite recursion error caused when rendering cyclical
 relations (close #7691)

---
 modules/svg/vertices.js | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/modules/svg/vertices.js b/modules/svg/vertices.js
index d7cd23ee4..27aa49148 100644
--- a/modules/svg/vertices.js
+++ b/modules/svg/vertices.js
@@ -300,7 +300,14 @@ export function svgVertices(projection, context) {
     function getSiblingAndChildVertices(ids, graph, wireframe, zoom) {
         var results = {};
 
+        var seenIds = {};
+
         function addChildVertices(entity) {
+
+            // avoid redunant work and infinite recursion of circular relations
+            if (seenIds[entity.id]) return;
+            seenIds[entity.id] = true;
+
             var geometry = entity.geometry(graph);
             if (!context.features().isHiddenFeature(entity, graph, geometry)) {
                 var i;