From 7e019057a9742286226d00cf5e95f4e99c795089 Mon Sep 17 00:00:00 2001
From: Alexey Antonov <alexwizp@gmail.com>
Date: Fri, 18 Sep 2020 16:18:44 +0300
Subject: [PATCH] Visualize: Bad request when working with histogram
 aggregation (#77684) (#77850)

* Visualize: Bad request when working with histogram aggregation

Closes: #77023

* :pencil2: Add some more fix context

* :white_check_mark: Add test

Co-authored-by: dej611 <dej611@gmail.com>
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>

Co-authored-by: dej611 <dej611@gmail.com>
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
---
 .../lib/histogram_calculate_interval.test.ts      | 13 +++++++++++++
 .../buckets/lib/histogram_calculate_interval.ts   | 15 +++++++--------
 2 files changed, 20 insertions(+), 8 deletions(-)

diff --git a/src/plugins/data/common/search/aggs/buckets/lib/histogram_calculate_interval.test.ts b/src/plugins/data/common/search/aggs/buckets/lib/histogram_calculate_interval.test.ts
index fd788d33392951..d3a95b32cd4250 100644
--- a/src/plugins/data/common/search/aggs/buckets/lib/histogram_calculate_interval.test.ts
+++ b/src/plugins/data/common/search/aggs/buckets/lib/histogram_calculate_interval.test.ts
@@ -139,6 +139,19 @@ describe('calculateHistogramInterval', () => {
           })
         ).toEqual(0.02);
       });
+
+      test('should correctly fallback to the default value for empty string', () => {
+        expect(
+          calculateHistogramInterval({
+            ...params,
+            maxBucketsUserInput: '',
+            values: {
+              min: 0.1,
+              max: 0.9,
+            },
+          })
+        ).toBe(0.01);
+      });
     });
   });
 });
diff --git a/src/plugins/data/common/search/aggs/buckets/lib/histogram_calculate_interval.ts b/src/plugins/data/common/search/aggs/buckets/lib/histogram_calculate_interval.ts
index f4e42fa8881ef5..378340e876296b 100644
--- a/src/plugins/data/common/search/aggs/buckets/lib/histogram_calculate_interval.ts
+++ b/src/plugins/data/common/search/aggs/buckets/lib/histogram_calculate_interval.ts
@@ -27,7 +27,7 @@ interface IntervalValuesRange {
 export interface CalculateHistogramIntervalParams {
   interval: string;
   maxBucketsUiSettings: number;
-  maxBucketsUserInput?: number;
+  maxBucketsUserInput?: number | '';
   intervalBase?: number;
   values?: IntervalValuesRange;
 }
@@ -77,12 +77,7 @@ const calculateForGivenInterval = (
      - The lower power of 10, times 2
      - The lower power of 10, times 5
  **/
-const calculateAutoInterval = (
-  diff: number,
-  maxBucketsUiSettings: CalculateHistogramIntervalParams['maxBucketsUiSettings'],
-  maxBucketsUserInput: CalculateHistogramIntervalParams['maxBucketsUserInput']
-) => {
-  const maxBars = Math.min(maxBucketsUiSettings, maxBucketsUserInput ?? maxBucketsUiSettings);
+const calculateAutoInterval = (diff: number, maxBars: number) => {
   const exactInterval = diff / maxBars;
 
   const lowerPower = Math.pow(10, Math.floor(Math.log10(exactInterval)));
@@ -122,7 +117,11 @@ export const calculateHistogramInterval = ({
 
     if (diff) {
       calculatedInterval = isAuto
-        ? calculateAutoInterval(diff, maxBucketsUiSettings, maxBucketsUserInput)
+        ? calculateAutoInterval(
+            diff,
+            // Mind maxBucketsUserInput can be an empty string, hence we need to ensure it here
+            Math.min(maxBucketsUiSettings, maxBucketsUserInput || maxBucketsUiSettings)
+          )
         : calculateForGivenInterval(diff, calculatedInterval, maxBucketsUiSettings);
     }
   }