treat trace w/ _length===0 as if they were visible:false

... after transform _module.calc loop

- that way filter transforms that remove all data coordinates
  don't result in errors
- of all the mocks listed in mock_lists.js, only 'scattercarpet' and
  'world-cals' still error out (wip)

src/components/fx/hover.js

@@ -370,10 +370,12 @@ function _hover(gd, evt, subplot, noHoverEvent) {
         cd = searchData[curvenum];
 
         // filter out invisible or broken data
-        if(!cd || !cd[0] || !cd[0].trace || cd[0].trace.visible !== true) continue;
+        if(!cd || !cd[0] || !cd[0].trace) continue;
 
         trace = cd[0].trace;
 
+        if(trace.visible !== true || trace._length === 0) continue;
+
         // Explicitly bail out for these two. I don't know how to otherwise prevent
         // the rest of this function from running and failing
         if(['carpet', 'contourcarpet'].indexOf(trace._module.name) !== -1) continue;

src/lib/filter_visible.js

@@ -32,7 +32,8 @@ function baseFilter(item) {
 }
 
 function calcDataFilter(item) {
-    return item[0].trace.visible === true;
+    var trace = item[0].trace;
+    return trace.visible === true && trace._length !== 0;
 }
 
 function isCalcData(cont) {

src/plot_api/subroutines.js

@@ -674,7 +674,7 @@ exports.redrawReglTraces = function(gd) {
         for(i = 0; i < fullData.length; i++) {
             var trace = fullData[i];
 
-            if(trace.visible === true) {
+            if(trace.visible === true && trace._length !== 0) {
                 if(trace.type === 'splom') {
                     fullLayout._splomScenes[trace.uid].draw();
                 } else if(trace.type === 'scattergl') {

src/plots/get_data.js

@@ -69,8 +69,10 @@ exports.getModuleCalcData = function(calcdata, arg1) {
     for(var i = 0; i < calcdata.length; i++) {
         var cd = calcdata[i];
         var trace = cd[0].trace;
-        // N.B. 'legendonly' traces do not make it past here
-        if(trace.visible !== true) continue;
+        // N.B.
+        // - 'legendonly' traces do not make it past here
+        // - skip over 'visible' traces that got trimmed completely during calc transforms
+        if(trace.visible !== true || trace._length === 0) continue;
 
         // group calcdata trace not by 'module' (as the name of this function
         // would suggest), but by 'module plot method' so that if some traces

src/plots/gl3d/scene.js

@@ -502,7 +502,7 @@ proto.plot = function(sceneData, fullLayout, layout) {
 
     for(i = 0; i < sceneData.length; ++i) {
         data = sceneData[i];
-        if(data.visible !== true) continue;
+        if(data.visible !== true || data._length === 0) continue;
 
         computeTraceBounds(this, data, dataBounds);
     }
@@ -526,7 +526,7 @@ proto.plot = function(sceneData, fullLayout, layout) {
     // Update traces
     for(i = 0; i < sceneData.length; ++i) {
         data = sceneData[i];
-        if(data.visible !== true) {
+        if(data.visible !== true || data._length === 0) {
             continue;
         }
         trace = this.traces[data.uid];
@@ -551,7 +551,8 @@ proto.plot = function(sceneData, fullLayout, layout) {
     traceIdLoop:
     for(i = 0; i < traceIds.length; ++i) {
         for(j = 0; j < sceneData.length; ++j) {
-            if(sceneData[j].uid === traceIds[i] && sceneData[j].visible === true) {
+            if(sceneData[j].uid === traceIds[i] &&
+                (sceneData[j].visible === true && sceneData[j]._length !== 0)) {
                 continue traceIdLoop;
             }
         }

src/plots/plots.js

@@ -2778,7 +2778,7 @@ plots.doCalcdata = function(gd, traces) {
 
         var cd = [];
 
-        if(trace.visible === true) {
+        if(trace.visible === true && trace._length !== 0) {
             // clear existing ref in case it got relinked
             delete trace._indexToPoints;
             // keep ref of index-to-points map object of the *last* enabled transform,

src/plots/polar/set_convert.js

@@ -174,6 +174,9 @@ function setConvertAngular(ax, polarLayout) {
                 var catLen = ax._categories.length;
                 var _period = ax.period ? Math.max(ax.period, catLen) : catLen;
 
+                // fallback in case all categories have been filtered out
+                if(_period === 0) _period = 1;
+
                 c2rad = t2rad = function(v) { return v * 2 * Math.PI / _period; };
                 rad2c = rad2t = function(v) { return v * _period / Math.PI / 2; };
 

src/traces/scattermapbox/convert.js

@@ -23,7 +23,7 @@ var convertTextOpts = require('../../plots/mapbox/convert_text_opts');
 module.exports = function convert(calcTrace) {
     var trace = calcTrace[0].trace;
 
-    var isVisible = (trace.visible === true);
+    var isVisible = (trace.visible === true && trace._length !== 0);
     var hasFill = (trace.fill !== 'none');
     var hasLines = subTypes.hasLines(trace);
     var hasMarkers = subTypes.hasMarkers(trace);

test/jasmine/tests/transform_filter_test.js

@@ -1319,3 +1319,67 @@ describe('filter transforms interactions', function() {
         .then(done);
     });
 });
+
+describe('filter resulting in empty coordinate arrays', function() {
+    afterEach(destroyGraphDiv);
+
+    function filter2empty(mock) {
+        var fig = Lib.extendDeep({}, mock);
+        var data = fig.data || [];
+
+        data.forEach(function(trace) {
+            trace.transforms = [{
+                type: 'filter',
+                target: [null]
+            }];
+        });
+
+        return fig;
+    }
+
+    describe('svg mocks', function() {
+        var mockList = require('../assets/mock_lists').svg;
+
+        mockList.forEach(function(d) {
+            if(d[0] === 'scattercarpet' || d[0] === 'world-cals') {
+                // scattercarpet don't work with transforms
+                // world-cals mock complains during a Lib.cleanDate()
+                return;
+            }
+
+            it(d[0], function(done) {
+                var gd = createGraphDiv();
+                var fig = filter2empty(d[1]);
+                Plotly.newPlot(gd, fig).catch(failTest).then(done);
+            });
+        });
+    });
+
+    describe('gl mocks', function() {
+        var mockList = require('../assets/mock_lists').gl;
+
+        mockList.forEach(function(d) {
+            it('@gl ' + d[0], function(done) {
+                var gd = createGraphDiv();
+                var fig = filter2empty(d[1]);
+                Plotly.newPlot(gd, fig).catch(failTest).then(done);
+            });
+        });
+    });
+
+    describe('mapbox mocks', function() {
+        var mockList = require('../assets/mock_lists').mapbox;
+
+        Plotly.setPlotConfig({
+            mapboxAccessToken: require('@build/credentials.json').MAPBOX_ACCESS_TOKEN
+        });
+
+        mockList.forEach(function(d) {
+            it('@noCI ' + d[0], function(done) {
+                var gd = createGraphDiv();
+                var fig = filter2empty(d[1]);
+                Plotly.newPlot(gd, fig).catch(failTest).then(done);
+            });
+        });
+    });
+});