fix namelength=0 case

Author: etpinard

src/components/fx/hover.js

@@ -1334,18 +1334,22 @@ function cleanPoint(d, hovermode) {
     var cd0 = d.cd[0];
     var cd = d.cd[index] || {};
 
+    function pass(v) {
+        return v || (isNumeric(v) && v === 0);
+    }
+
     var getVal = Array.isArray(index) ?
         function(calcKey, traceKey) {
-            return Lib.castOption(cd0, index, calcKey) ||
-                Lib.extractOption({}, trace, '', traceKey);
+            var v = Lib.castOption(cd0, index, calcKey);
+            return pass(v) ? v : Lib.extractOption({}, trace, '', traceKey);
         } :
         function(calcKey, traceKey) {
             return Lib.extractOption(cd, trace, calcKey, traceKey);
         };
 
     function fill(key, calcKey, traceKey) {
         var val = getVal(calcKey, traceKey);
-        if(val) d[key] = val;
+        if(pass(val)) d[key] = val;
     }
 
     fill('hoverinfo', 'hi', 'hoverinfo');

test/jasmine/tests/hover_label_test.js

@@ -805,6 +805,40 @@ describe('hover info', function() {
                     name: 'trace one'
                 });
             })
+            .then(function() {
+                var nl = [[0, 0, 0], [0, 0, 0]];
+                return Plotly.restyle(gd, 'hoverlabel.namelength', [nl, nl]);
+            })
+            .then(function() {
+                // hoverlabel.namelength has no effect when <extra></extra> is set
+                _hover(gd, 250, 50);
+                assertHoverLabelContent({
+                    nums: '(1,3) -- 2',
+                    name: 'trace two'
+                });
+
+                _hover(gd, 250, 300);
+                assertHoverLabelContent({
+                    nums: '(1,1) -- 5.56',
+                    name: 'trace one'
+                });
+            })
+            .then(function() {
+                return Plotly.restyle(gd, 'hovertemplate', null);
+            })
+            .then(function() {
+                _hover(gd, 250, 50);
+                assertHoverLabelContent({
+                    nums: 'x: 1\ny: 3\nz: 2\nY',
+                    name: ''
+                });
+
+                _hover(gd, 250, 300);
+                assertHoverLabelContent({
+                    nums: 'x: 1\ny: 1\nz: 5.56\nY',
+                    name: ''
+                });
+            })
             .catch(failTest)
             .then(done);
         });
@@ -929,6 +963,22 @@ describe('hover info', function() {
                     name: 'one'
                 });
             })
+            .then(function() {
+                return Plotly.restyle(gd, 'hoverlabel.namelength', 0);
+            })
+            .then(function() {
+                _hover(gd, 250, 100);
+                assertHoverLabelContent({
+                    nums: 'f(1.000,3.000)=2',
+                    name: ''
+                });
+
+                _hover(gd, 250, 300);
+                assertHoverLabelContent({
+                    nums: 'f(1.000,1.000)=5.56',
+                    name: ''
+                });
+            })
             .catch(failTest)
             .then(done);
         });