Fix rangeslider "fixed" rangemode using placeholder range of autoranged counter axis

draftlogs/7967_fix.md

@@ -0,0 +1 @@
+- Fix range slider drawing spurious grey bands on initial render when `rangeslider.yaxis.rangemode` is `"fixed"` and the counter axis is autoranged [[#7967](https://github.com/plotly/plotly.js/pull/7967)]

src/components/rangeslider/defaults.js

@@ -67,6 +67,10 @@ module.exports = function handleDefaults(layoutIn, layoutOut, axName) {
             var rangeMode = coerceRange('rangemode', rangemodeDflt);
             if(rangeMode !== 'match') {
                 coerceRange('range', yAxOut.range.slice());
+
+                if(rangeMode === 'fixed' && !rangemodeDflt && yAxOut.autorange) {
+                    rangeContainerOut._rangeDfltFromAutorangedAx = true;
+                }
             }
         }
     }

src/plots/cartesian/autorange.js

@@ -398,8 +398,9 @@ function doAutoRange(gd, ax, presetRange) {
     if(anchorAx && anchorAx.rangeslider) {
         var axeRangeOpts = anchorAx.rangeslider[ax._name];
         if(axeRangeOpts) {
-            if(axeRangeOpts.rangemode === 'auto') {
+            if(axeRangeOpts.rangemode === 'auto' || axeRangeOpts._rangeDfltFromAutorangedAx) {
                 axeRangeOpts.range = getAutoRange(gd, ax);
+                delete axeRangeOpts._rangeDfltFromAutorangedAx;
             }
         }
         anchorAx._input.rangeslider[ax._name] = Lib.extendFlat({}, axeRangeOpts);

test/jasmine/tests/range_slider_test.js

@@ -1127,6 +1127,30 @@ describe('rangesliders in general', function() {
         .then(done, done.fail);
     });
 
+    it('should not leave "fixed" rangemode on the placeholder range of an autoranged counter axis', function(done) {
+        Plotly.newPlot(gd, [{
+            // use a heatmap because it doesn't add any padding
+            x0: 0, dx: 1,
+            y0: 1, dy: 1,
+            z: [[1, 2, 3], [2, 3, 4], [3, 4, 5]],
+            type: 'heatmap'
+        }], {
+            xaxis: {
+                rangeslider: {visible: true, yaxis: {rangemode: 'fixed'}}
+            }
+        })
+        .then(function() {
+            expect(gd._fullLayout.yaxis.range).toBeCloseToArray([0.5, 3.5], 3);
+            expect(gd._fullLayout.xaxis.rangeslider.yaxis.range).toBeCloseToArray([0.5, 3.5], 3);
+            return Plotly.restyle(gd, {dy: 4});
+        })
+        .then(function() {
+            expect(gd._fullLayout.yaxis.range).toBeCloseToArray([-1, 11], 3);
+            expect(gd._fullLayout.xaxis.rangeslider.yaxis.range).toBeCloseToArray([0.5, 3.5], 3);
+        })
+        .then(done, done.fail);
+    });
+
     it('should be able to turn on rangeslider x/y autorange implicitly by deleting x range', function(done) {
         // this does not apply to y ranges, because the default there is 'match'
         Plotly.newPlot(gd, [{