From c4dd6e6b04df4d0a830f6fe680783ecde2b7d96c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maximilian=20Kr=C3=B6g?= <maxi_kroeg@web.de>
Date: Sun, 6 Dec 2020 15:25:31 +0100
Subject: [PATCH] Fixes Modify vertex insertion with duplicate segments

If one feature has duplicate segments it prevented insertion for other
features with the same segment.
---
 src/ol/interaction/Modify.js | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/ol/interaction/Modify.js b/src/ol/interaction/Modify.js
index f12d6685c0..3c946bffc4 100644
--- a/src/ol/interaction/Modify.js
+++ b/src/ol/interaction/Modify.js
@@ -1097,14 +1097,16 @@ class Modify extends PointerInteraction {
           for (let i = 1, ii = nodes.length; i < ii; ++i) {
             const segment = nodes[i].segment;
             if (
-              ((coordinatesEqual(closestSegment[0], segment[0]) &&
+              (coordinatesEqual(closestSegment[0], segment[0]) &&
                 coordinatesEqual(closestSegment[1], segment[1])) ||
-                (coordinatesEqual(closestSegment[0], segment[1]) &&
-                  coordinatesEqual(closestSegment[1], segment[0]))) &&
-              !(getUid(nodes[i].geometry) in geometries)
+              (coordinatesEqual(closestSegment[0], segment[1]) &&
+                coordinatesEqual(closestSegment[1], segment[0]))
             ) {
-              geometries[getUid(nodes[i].geometry)] = true;
-              vertexSegments[getUid(segment)] = true;
+              const geometryUid = getUid(nodes[i].geometry);
+              if (!(geometryUid in geometries)) {
+                geometries[geometryUid] = true;
+                vertexSegments[getUid(segment)] = true;
+              }
             } else {
               break;
             }