From d025741b86ad7fe2136c0b99d19f013d1924e836 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=89tienne=20T=C3=A9treault-Pinard?= <etienne@plot.ly>
Date: Wed, 22 May 2019 17:23:13 -0400
Subject: [PATCH] use correct index to lookup unique histogram2d y vals

---
 src/traces/histogram2d/calc.js         |  4 ++--
 test/jasmine/tests/hover_label_test.js | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/traces/histogram2d/calc.js b/src/traces/histogram2d/calc.js
index c1d08ae2f27..480140442e2 100644
--- a/src/traces/histogram2d/calc.js
+++ b/src/traces/histogram2d/calc.js
@@ -149,8 +149,8 @@ module.exports = function calc(gd, trace) {
                 else if(xVals[n] !== xi) uniqueValsPerX = false;
             }
             if(uniqueValsPerY) {
-                if(yVals[n] === undefined) yVals[n] = yi;
-                else if(yVals[n] !== yi) uniqueValsPerY = false;
+                if(yVals[m] === undefined) yVals[m] = yi;
+                else if(yVals[m] !== yi) uniqueValsPerY = false;
             }
 
             xGapLow = Math.min(xGapLow, xi - xEdges[n]);
diff --git a/test/jasmine/tests/hover_label_test.js b/test/jasmine/tests/hover_label_test.js
index 6b3e6192684..068ff1c11b6 100644
--- a/test/jasmine/tests/hover_label_test.js
+++ b/test/jasmine/tests/hover_label_test.js
@@ -1225,6 +1225,26 @@ describe('hover info', function() {
             .then(done);
         });
 
+        it('shows the data range when bins have multiple values (case 2)', function(done) {
+            var gd = createGraphDiv();
+
+            Plotly.plot(gd, [{
+                type: 'histogram2d',
+                x: ['a', 'b', 'c', 'a'],
+                y: [7, 2, 3, 7],
+                nbinsy: 3
+            }], {
+                width: 600,
+                height: 600
+            })
+            .then(function() {
+                _hover(gd, 250, 200);
+                assertHoverLabelContent({nums: ['x: b', 'y: 4 - 5', 'z: 0'].join('\n')});
+            })
+            .catch(failTest)
+            .then(done);
+        });
+
         it('shows the exact data when bins have single values', function(done) {
             var gd = createGraphDiv();