zoomToEntity fails when selecting a relation from the search results

[bhousel]

What is supposed to happen:

You click on Philadelphia in the geocoder search results and the map moves to someplace around Philadelphia.

What happens:

The map doesn't actually go anywhere.

Why:

We fetch the Philadelphia relation from the OSM API using this zoomToEntity function:

iD/modules/core/context.js

Lines 118 to 126 in c0d224b

	context.zoomToEntity = function(id, zoomTo) {
	if (zoomTo !== false) {
	this.loadEntity(id, function(err, result) {
	if (err) return;
	var entity = _.find(result.data, function(e) { return e.id === id; });
	if (entity) { map.zoomTo(entity); }
	});
	}

It fetches the relation, but not the members, and so when map.zoomTo() tries to calculate an extent, it can't actually do this, and just returns without moving the map anywhere:

iD/modules/renderer/map.js

Lines 650 to 652 in c0d224b

	map.zoomTo = function(entity, zoomLimits) {
	var extent = entity.extent(context.graph());
	if (!isFinite(extent.area())) return;

Interestingly, if you try these steps a second time, iD will actually go to Philadelphia because somehow some of its relation members got loaded. I'm curious about how/where that happens, because it's not something I expected.

[willemarcel]

I couldn't reproduce with nodes, but this happens with ways that aren't part of relations.

[JamesKingdom]

The sidebar also opens and is buggy if you go direct to a relation from a url, here's an example.

You are left at zoom 2 at 0,0, and if anything updates, the sidebar closes and changes to Zoom in to edit

[Zverik]

Heard a complaint about this from a fellow mapper. A test case: www.openstreetmap.org/edit?way=26233048 should zoom to way, but currently it shows the whole world. I understand this is not easy fixable and not of priority, but still it would be nice to have.

Maybe you could query the Overpass API for a quick fix? Something like [out:json];way(id:12345);out center;

[1ec5]

The same thing happens if you search for a way or node ID, like w26233048. As in the original post, iD zooms and pans correctly the second time you search for that ID and select the result.

[bhousel]

Looking at it more, the issue is probably this block of code.

We can delay fetching and parsing the tiles, but we shouldn't delay history.merge. The code below will call the loadTiles and loadEntity callbacks before those entities are actually merged into the graph. This is almost certainly causing a bunch of random issues, including the intermittent history restore and conflict resolution bugs some people are reporting.

iD/modules/core/context.js

Lines 114 to 144 in 9fa078b

	/* Connection */
	var entitiesLoaded = utilCallWhenIdle(function entitiesLoaded(err, result) {
	if (!err) history.merge(result.data, result.extent);
	});
	context.preauth = function(options) {
	if (connection) {
	connection.switch(options);
	}
	return context;
	};
	context.loadTiles = utilCallWhenIdle(function(projection, dimensions, callback) {
	function done(err, result) {
	entitiesLoaded(err, result);
	if (callback) callback(err, result);
	}
	if (connection) {
	connection.loadTiles(projection, dimensions, done);
	}
	});
	context.loadEntity = function(id, callback) {
	function done(err, result) {
	entitiesLoaded(err, result);
	if (callback) callback(err, result);
	}
	if (connection) {
	connection.loadEntity(id, done);
	}
	};

[Zverik]

It works! Thank you, Bryan!