show stacked charts and stacking options with one series (#10067)

frontend/src/metabase/visualizations/lib/renderer_utils.js

@@ -132,10 +132,8 @@ export const isOrdinal = settings =>
 export const isHistogramBar = ({ settings, chartType }) =>
   isHistogram(settings) && chartType === "bar";
 
-export const isStacked = (settings, datas) =>
-  settings["stackable.stack_type"] && datas.length > 1;
+export const isStacked = (settings, datas) => settings["stackable.stack_type"];
 export const isNormalized = (settings, datas) =>
-  isStacked(settings, datas) &&
   settings["stackable.stack_type"] === "normalized";
 
 // find the first nonempty single series

frontend/src/metabase/visualizations/lib/settings/graph.js

@@ -273,9 +273,6 @@ export const STACKABLE_SETTINGS = {
         ? "stacked"
         : null,
     getHidden: (series, settings) => {
-      if (series.length < 2) {
-        return true;
-      }
       const displays = series.map(single => settings.series(single).display);
       return !_.any(displays, display => STACKABLE_DISPLAY_TYPES.has(display));
     },

frontend/test/metabase/visualizations/components/LineAreaBarRenderer-bar.unit.spec.js

@@ -27,7 +27,7 @@ const DEFAULT_COLUMN_SETTINGS = {
   date_style: "MMMM D, YYYY",
 };
 
-function MainSeries(chartType, settings = {}) {
+function MainSeries(chartType, settings = {}, value = 1) {
   return {
     card: {
       display: chartType,
@@ -41,7 +41,7 @@ function MainSeries(chartType, settings = {}) {
         StringColumn({ display_name: "Category", source: "breakout" }),
         NumberColumn({ display_name: "Sum", source: "aggregation" }),
       ],
-      rows: [["A", 1]],
+      rows: [["A", value]],
     },
   };
 }
@@ -159,6 +159,23 @@ describe("LineAreaBarRenderer-bar", () => {
     ]);
   });
 
+  it(`should render an bar normalized chart with just one series`, () => {
+    const onHoverChange = jest.fn();
+    renderLineAreaBar(
+      element,
+      [MainSeries("bar", { "stackable.stack_type": "normalized" }, 3)],
+      { onHoverChange },
+    );
+
+    dispatchUIEvent(qsa(".bar, .dot")[0], "mousemove");
+
+    const { calls } = onHoverChange.mock;
+    expect(getDataKeyValues(calls[0][0])).toEqual([
+      { key: "Category", value: "A" },
+      { key: "% Sum", value: "100%" },
+    ]);
+  });
+
   it("should replace the aggregation name with the series name", () => {
     const onHoverChange = jest.fn();
     renderLineAreaBar(