From 0440054cd92e321c21a0ea5ea74a0ec3f29d446d Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Fri, 27 Jan 2017 13:02:27 -0500
Subject: [PATCH] Child and sibling vertices should be eligible for drag_node
 (closes #3799, see also #3801)

---
 modules/modes/drag_node.js | 21 ++++++++++++---------
 modules/svg/vertices.js    | 11 +++++++----
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/modules/modes/drag_node.js b/modules/modes/drag_node.js
index e0d9ca771..575df3a05 100644
--- a/modules/modes/drag_node.js
+++ b/modules/modes/drag_node.js
@@ -81,17 +81,18 @@ export function modeDragNode(context) {
     function start(entity) {
         wasMidpoint = entity.type === 'midpoint';
 
-        var editableIDs = [ entity.id ];
-        context.graph().parentWays(entity).forEach(function (parentWay) {
-            editableIDs.push(parentWay.id);
-            editableIDs = editableIDs.concat(_.map(context.graph().parentRelations(parentWay), 'id'));
-        });
+        // vertices classed "sibling" include:  (see svg/vertices.js)
+        // - children of selected ways or multipolygons
+        // - vertices sharing a way with selected vertices
+        var selection = d3.selectAll('g.' + entity.id),
+            isSibling = !selection.empty() && selection.classed('sibling');
 
-        isCancelled = d3.event.sourceEvent.shiftKey ||
-            !(wasMidpoint || _.some(editableIDs, function (editableID) { return selectedIDs.indexOf(editableID) !== -1; })) ||
+        isCancelled = d3.event.sourceEvent.shiftKey || !(wasMidpoint || isSibling) ||
             context.features().hasHiddenConnections(entity, context.graph());
 
-        if (isCancelled) return behavior.cancel();
+        if (isCancelled) {
+            return behavior.cancel();
+        }
 
         if (wasMidpoint) {
             var midpoint = entity;
@@ -105,10 +106,12 @@ export function modeDragNode(context) {
             context.perform(actionNoop());
         }
 
+        // activeIDs generate no pointer events.  This prevents the node or vertex
+        // being dragged from trying to connect to itself or its parent element.
         activeIDs = _.map(context.graph().parentWays(entity), 'id');
         activeIDs.push(entity.id);
-
         setActiveElements();
+
         context.enter(mode);
     }
 
diff --git a/modules/svg/vertices.js b/modules/svg/vertices.js
index d3a850768..14897d8bf 100644
--- a/modules/svg/vertices.js
+++ b/modules/svg/vertices.js
@@ -53,7 +53,7 @@ export function svgVertices(projection, context) {
     }
 
 
-    function draw(selection, vertices, klass, graph, zoom) {
+    function draw(selection, vertices, klass, graph, zoom, siblings) {
 
         function icon(entity) {
             if (entity.id in icons) return icons[entity.id];
@@ -105,6 +105,8 @@ export function svgVertices(projection, context) {
         }
 
 
+        siblings = siblings || {};
+
         var icons = {},
             z = (zoom < 17 ? 0 : zoom < 18 ? 1 : 2);
 
@@ -141,6 +143,7 @@ export function svgVertices(projection, context) {
         groups
             .merge(enter)
             .attr('transform', svgPointTransform(projection))
+            .classed('sibling', function(entity) { return entity.id in siblings; })
             .classed('shared', function(entity) { return graph.isShared(entity); })
             .classed('endpoint', function(entity) { return entity.isEndpoint(graph); })
             .call(setAttributes);
@@ -148,7 +151,7 @@ export function svgVertices(projection, context) {
 
 
     function drawVertices(selection, graph, entities, filter, extent, zoom) {
-        var selected = siblingAndChildVertices(context.selectedIDs(), graph, extent),
+        var siblings = siblingAndChildVertices(context.selectedIDs(), graph, extent),
             wireframe = context.surface().classed('fill-wireframe'),
             vertices = [];
 
@@ -164,7 +167,7 @@ export function svgVertices(projection, context) {
             if (geometry !== 'vertex')
                 continue;
 
-            if (entity.id in selected ||
+            if (entity.id in siblings ||
                 entity.hasInterestingTags() ||
                 entity.isEndpoint(graph) ||
                 entity.isConnected(graph)) {
@@ -175,7 +178,7 @@ export function svgVertices(projection, context) {
         var layer = selection.selectAll('.layer-hit');
         layer.selectAll('g.vertex.vertex-persistent')
             .filter(filter)
-            .call(draw, vertices, 'vertex-persistent', graph, zoom);
+            .call(draw, vertices, 'vertex-persistent', graph, zoom, siblings);
 
         drawHover(selection, graph, extent, zoom);
     }