From 9c35c15d7ddb3bd6e0e66512abdedc23f7fd9e25 Mon Sep 17 00:00:00 2001
From: Marco Liberati <dej611@users.noreply.github.com>
Date: Wed, 21 Aug 2024 16:36:27 +0200
Subject: [PATCH] [Lens] Fix no data collapse by scenario with Metric chart
 (#190966)

## Summary

Fixes #182628

This PR provides a fix for the editor crash on no data when using
collapsing by.
In addition the rendering of no data in such scenario now matches the no
data rendering with a single tile.

<img width="533" alt="Screenshot 2024-08-21 at 12 57 43"
src="https://github.com/user-attachments/assets/71c40e3b-5e1a-48f1-a03f-5a4a5774e9d7">
<img width="1008" alt="Screenshot 2024-08-21 at 12 57 28"
src="https://github.com/user-attachments/assets/e35b9612-743b-412e-9565-0afcb5fd8735">
<img width="1229" alt="Screenshot 2024-08-21 at 12 56 31"
src="https://github.com/user-attachments/assets/f64f38f8-8995-4214-9954-386aac62f0c7">


### Checklist

- [x] [Unit or functional
tests](https://www.elastic.co/guide/en/kibana/master/development-tests.html)
were updated or added to match the most common scenarios
---
 .../public/components/metric_vis.test.tsx     | 24 ++++++++++++-------
 .../public/components/metric_vis.tsx          | 11 +++++++--
 2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/src/plugins/chart_expressions/expression_metric/public/components/metric_vis.test.tsx b/src/plugins/chart_expressions/expression_metric/public/components/metric_vis.test.tsx
index 3687113d9aee0..7311adee7a202 100644
--- a/src/plugins/chart_expressions/expression_metric/public/components/metric_vis.test.tsx
+++ b/src/plugins/chart_expressions/expression_metric/public/components/metric_vis.test.tsx
@@ -428,14 +428,12 @@ describe('MetricVisComponent', function () {
 
       const [[visConfig]] = component.find(Metric).props().data!;
 
-      expect(visConfig!.value).toMatchInlineSnapshot(
-        `
+      expect(visConfig!.value).toMatchInlineSnapshot(`
         Array [
           "text-28.984375",
           "text-100",
         ]
-      `
-      );
+      `);
     });
 
     it('should display multi-values numeric values formatted and without quotes', () => {
@@ -451,14 +449,24 @@ describe('MetricVisComponent', function () {
 
       const [[visConfig]] = component.find(Metric).props().data!;
 
-      expect(visConfig!.value).toMatchInlineSnapshot(
-        `
+      expect(visConfig!.value).toMatchInlineSnapshot(`
         Array [
           "number-28.984375",
           "number-100",
         ]
-      `
-      );
+      `);
+    });
+
+    it('should display an empty tile if no data is provided', () => {
+      const newTable = {
+        ...table,
+        rows: [],
+      };
+      const component = shallow(<MetricVis config={config} data={newTable} {...defaultProps} />);
+
+      const [[visConfig]] = component.find(Metric).props().data!;
+
+      expect(visConfig!.value).toMatchInlineSnapshot(`NaN`);
     });
   });
 
diff --git a/src/plugins/chart_expressions/expression_metric/public/components/metric_vis.tsx b/src/plugins/chart_expressions/expression_metric/public/components/metric_vis.tsx
index 4ed15f5f72554..d0f6b6f3399e6 100644
--- a/src/plugins/chart_expressions/expression_metric/public/components/metric_vis.tsx
+++ b/src/plugins/chart_expressions/expression_metric/public/components/metric_vis.tsx
@@ -163,7 +163,7 @@ export const MetricVis = ({
   );
 
   const onWillRender = useCallback(() => {
-    const maxTileSideLength = grid.current.length * grid.current[0].length > 1 ? 200 : 300;
+    const maxTileSideLength = grid.current.length * grid.current[0]?.length > 1 ? 200 : 300;
     const event: ChartSizeEvent = {
       name: 'chartSize',
       data: {
@@ -197,8 +197,15 @@ export const MetricVis = ({
     ? getColumnByAccessor(config.dimensions.max, data.columns)?.id
     : undefined;
 
+  // For a sigle tile configuration, either no breakdown or with a collapse by, provide
+  // a fallback in case of missing data. Make sure to provide an exact "null" value to render a N/A metric.
+  // For reference, undefined will render as - instead of N/A and it is used in a breakdown scenario
+  const firstRowForNonBreakdown = (
+    data.rows.length ? data.rows : [{ [primaryMetricColumn.id]: null }]
+  ).slice(0, 1);
+
   const metricConfigs: MetricSpec['data'][number] = (
-    breakdownByColumn ? data.rows : data.rows.slice(0, 1)
+    breakdownByColumn ? data.rows : firstRowForNonBreakdown
   ).map((row, rowIdx) => {
     const value: number | string =
       row[primaryMetricColumn.id] !== null ? row[primaryMetricColumn.id] : NaN;