validate cornerradius value in supply defaults

src/traces/bar/defaults.js

@@ -1,5 +1,7 @@
 'use strict';
 
+var isNumeric = require('fast-isnumeric');
+
 var Lib = require('../../lib');
 var Color = require('../../components/color');
 var Registry = require('../../registry');
@@ -69,16 +71,40 @@ function crossTraceDefaults(fullData, fullLayout) {
 
         if(traceOut.type === 'bar') {
             traceIn = traceOut._input;
-            // This needs to happen here rather than in handleStyleDefaults() because
-            // it needs to happen after `layout.barcornerradius` has been coerced
-            coerce('marker.cornerradius', fullLayout.barcornerradius);
+            // `marker.cornerradius` needs to be coerced here rather than in handleStyleDefaults()
+            // because it needs to happen after `layout.barcornerradius` has been coerced
+            var r = coerce('marker.cornerradius', fullLayout.barcornerradius);
+            traceOut.marker.cornerradius = validateCornerradius(r);
+
             if(fullLayout.barmode === 'group') {
                 handleGroupingDefaults(traceIn, traceOut, fullLayout, coerce);
             }
         }
     }
 }
 
+// Returns a value equivalent to the given cornerradius value, if valid;
+// otherwise returns`undefined`.
+// Valid cornerradius values must be either:
+//   - a numeric value (string or number) >= 0, or
+//   - a string consisting of a number >= 0 followed by a % sign
+// If the given cornerradius value is a numeric string, it will be converted
+// to a number.
+function validateCornerradius(r) {
+    var validR = false;
+    if(isNumeric(r)) {
+        r = +r;
+        if(r >= 0) validR = true;
+    } else if(typeof r === 'string' && r.slice(-1) === '%') {
+        r = +r.slice(0, -1);
+        if(r >= 0) {
+            r += '%';
+            validR = true;
+        }
+    }
+    return validR ? r : undefined;
+}
+
 function handleText(traceIn, traceOut, layout, coerce, textposition, opts) {
     opts = opts || {};
     var moduleHasSelected = !(opts.moduleHasSelected === false);

src/traces/bar/plot.js

@@ -256,7 +256,7 @@ function plot(gd, plotinfo, cdModule, traceLayer, opts, makeOnCompleteCallback)
                 } else if(isNumeric(radiusParam)) {
                     // If radius is already given as a number of pixels, use the given value
                     rPx = +radiusParam;
-                } else if(typeof radiusParam === 'string' && radiusParam.slice(-1) === '%') {
+                } else if(typeof radiusParam === 'string') {
                     // Otherwise, if % string, convert to number of pixels
                     var rPercent = Math.min(50, +radiusParam.slice(0, -1));
                     rPx = barWidth * (rPercent / 100);

src/traces/histogram/cross_trace_defaults.js

@@ -5,6 +5,7 @@ var axisIds = require('../../plots/cartesian/axis_ids');
 
 var traceIs = require('../../registry').traceIs;
 var handleGroupingDefaults = require('../scatter/grouping_defaults');
+var validateCornerradius = require('../bar/defaults').validateCornerradius;
 
 var nestedProperty = Lib.nestedProperty;
 var getAxisGroup = require('../../plots/cartesian/constraints').getAxisGroup;
@@ -100,8 +101,10 @@ module.exports = function crossTraceDefaults(fullData, fullLayout) {
             // https://github.com/plotly/plotly.js/issues/749
             delete traceOut._xautoBinFinished;
             delete traceOut._yautoBinFinished;
+
             if(traceOut.type === 'histogram') {
-                coerce('marker.cornerradius', fullLayout.barcornerradius);
+                var r = coerce('marker.cornerradius', fullLayout.barcornerradius);
+                traceOut.marker.cornerradius = validateCornerradius(r);
             }
 
             // N.B. need to coerce *alignmentgroup* before *bingroup*, as traces