Remove nested root from index pattern (#54978)

* Revert "Add label and icon to nested fields in the doc table (#54199)"

This reverts commit f77b362

* Apply label and icon to nested fields in the doc table

* Add nested type to field_icon

* Improve nested test and add comment

* Fix tests

* Always pass the field type

src/legacy/core_plugins/kibana/public/discover/np_ready/components/table/table.test.tsx

@@ -26,50 +26,48 @@ import { IndexPattern, indexPatterns } from '../../../kibana_services';
 
 jest.mock('ui/new_platform');
 
-// @ts-ignore
 const indexPattern = {
-  fields: {
-    getByName: (name: string) => {
-      const fields: { [name: string]: {} } = {
-        _index: {
-          name: '_index',
-          type: 'string',
-          scripted: false,
-          filterable: true,
-        },
-        message: {
-          name: 'message',
-          type: 'string',
-          scripted: false,
-          filterable: false,
-        },
-        extension: {
-          name: 'extension',
-          type: 'string',
-          scripted: false,
-          filterable: true,
-        },
-        bytes: {
-          name: 'bytes',
-          type: 'number',
-          scripted: false,
-          filterable: true,
-        },
-        scripted: {
-          name: 'scripted',
-          type: 'number',
-          scripted: true,
-          filterable: false,
-        },
-      };
-      return fields[name];
+  fields: [
+    {
+      name: '_index',
+      type: 'string',
+      scripted: false,
+      filterable: true,
+    },
+    {
+      name: 'message',
+      type: 'string',
+      scripted: false,
+      filterable: false,
+    },
+    {
+      name: 'extension',
+      type: 'string',
+      scripted: false,
+      filterable: true,
     },
-  },
+    {
+      name: 'bytes',
+      type: 'number',
+      scripted: false,
+      filterable: true,
+    },
+    {
+      name: 'scripted',
+      type: 'number',
+      scripted: true,
+      filterable: false,
+    },
+  ],
   metaFields: ['_index', '_score'],
   flattenHit: undefined,
   formatHit: jest.fn(hit => hit._source),
 } as IndexPattern;
 
+indexPattern.fields.getByName = (name: string) => {
+  return indexPattern.fields.find(field => field.name === name);
+};
+
 indexPattern.flattenHit = indexPatterns.flattenHitWrapper(indexPattern, indexPattern.metaFields);
 
 describe('DocViewTable at Discover', () => {

src/legacy/core_plugins/kibana/public/discover/np_ready/components/table/table.tsx

@@ -17,6 +17,7 @@
  * under the License.
  */
 import React, { useState } from 'react';
+import { escapeRegExp } from 'lodash';
 import { DocViewTableRow } from './table_row';
 import { arrayContainsObjects, trimAngularSpan } from './table_helper';
 import { DocViewRenderProps } from '../../doc_views/doc_views_types';
@@ -68,11 +69,57 @@ export function DocViewTable({
             const displayNoMappingWarning =
               !mapping(field) && !displayUnderscoreWarning && !isArrayOfObjects;
 
+            // Discover doesn't flatten arrays of objects, so for documents with an `object` or `nested` field that
+            // contains an array, Discover will only detect the top level root field. We want to detect when those
+            // root fields are `nested` so that we can display the proper icon and label. However, those root
+            // `nested` fields are not a part of the index pattern. Their children are though, and contain nested path
+            // info. So to detect nested fields we look through the index pattern for nested children
+            // whose path begins with the current field. There are edge cases where
+            // this could incorrectly identify a plain `object` field as `nested`. Say we had the following document
+            // where `foo` is a plain object field and `bar` is a nested field.
+            // {
+            //   "foo": [
+            //   {
+            //     "bar": [
+            //       {
+            //         "baz": "qux"
+            //       }
+            //     ]
+            //   },
+            //   {
+            //     "bar": [
+            //       {
+            //         "baz": "qux"
+            //       }
+            //     ]
+            //   }
+            // ]
+            // }
+            //
+            // The following code will search for `foo`, find it at the beginning of the path to the nested child field
+            // `foo.bar.baz` and incorrectly mark `foo` as nested. Any time we're searching for the name of a plain object
+            // field that happens to match a segment of a nested path, we'll get a false positive.
+            // We're aware of this issue and we'll have to live with
+            // it in the short term. The long term fix will be to add info about the `nested` and `object` root fields
+            // to the index pattern, but that has its own complications which you can read more about in the following
+            // issue: https://github.com/elastic/kibana/issues/54957
+            const isNestedField =
+              !indexPattern.fields.find(patternField => patternField.name === field) &&
+              !!indexPattern.fields.find(patternField => {
+                // We only want to match a full path segment
+                const nestedRootRegex = new RegExp(escapeRegExp(field) + '(\\.|$)');
+                return nestedRootRegex.test(patternField.subType?.nested?.path ?? '');
+              });
+            const fieldType = isNestedField
+              ? 'nested'
+              : indexPattern.fields.find(patternField => patternField.name === field)?.type;
+
             return (
               <DocViewTableRow
                 key={field}
                 field={field}
                 fieldMapping={mapping(field)}
+                fieldType={fieldType}
                 displayUnderscoreWarning={displayUnderscoreWarning}
                 displayNoMappingWarning={displayNoMappingWarning}
                 isCollapsed={isCollapsed}

src/legacy/core_plugins/kibana/public/discover/np_ready/components/table/table_row.tsx

@@ -31,6 +31,7 @@ import { DocViewTableRowIconUnderscore } from './table_row_icon_underscore';
 export interface Props {
   field: string;
   fieldMapping?: FieldMapping;
+  fieldType?: string;
   displayNoMappingWarning: boolean;
   displayUnderscoreWarning: boolean;
   isCollapsible: boolean;
@@ -46,6 +47,7 @@ export interface Props {
 export function DocViewTableRow({
   field,
   fieldMapping,
+  fieldType,
   displayNoMappingWarning,
   displayUnderscoreWarning,
   isCollapsible,
@@ -85,7 +87,7 @@ export function DocViewTableRow({
         </td>
       )}
       <td className="kbnDocViewer__field">
-        <FieldName field={fieldMapping} fieldName={field} />
+        <FieldName field={fieldMapping} fieldName={field} fieldType={fieldType} />
       </td>
       <td>
         {isCollapsible && (

src/plugins/data/server/index_patterns/fetcher/lib/field_capabilities/field_caps_response.test.js

@@ -37,7 +37,7 @@ describe('index_patterns/field_capabilities/field_caps_response', () => {
     describe('conflicts', () => {
       it('returns a field for each in response, no filtering', () => {
         const fields = readFieldCapsResponse(esResponse);
-        expect(fields).toHaveLength(25);
+        expect(fields).toHaveLength(24);
       });
 
       it(
@@ -68,8 +68,8 @@ describe('index_patterns/field_capabilities/field_caps_response', () => {
         sandbox.spy(shouldReadFieldFromDocValuesNS, 'shouldReadFieldFromDocValues');
         const fields = readFieldCapsResponse(esResponse);
         const conflictCount = fields.filter(f => f.type === 'conflict').length;
-        // +1 is for the object field which is filtered out of the final return value from readFieldCapsResponse
-        sinon.assert.callCount(shouldReadFieldFromDocValues, fields.length - conflictCount + 1);
+        // +2 is for the object and nested fields which get filtered out of the final return value from readFieldCapsResponse
+        sinon.assert.callCount(shouldReadFieldFromDocValues, fields.length - conflictCount + 2);
       });
 
       it('converts es types to kibana types', () => {
@@ -159,12 +159,10 @@ describe('index_patterns/field_capabilities/field_caps_response', () => {
         });
       });
 
-      it('returns the nested parent as not searchable or aggregatable', () => {
+      it('does not include the field actually mapped as nested itself', () => {
         const fields = readFieldCapsResponse(esResponse);
         const child = fields.find(f => f.name === 'nested_object_parent');
-        expect(child.type).toBe('nested');
-        expect(child.aggregatable).toBe(false);
-        expect(child.searchable).toBe(false);
+        expect(child).toBeUndefined();
       });
 
       it('should not confuse object children for multi or nested field children', () => {

src/plugins/data/server/index_patterns/fetcher/lib/field_capabilities/field_caps_response.ts

@@ -195,6 +195,6 @@ export function readFieldCapsResponse(fieldCapsResponse: FieldCapsResponse): Fie
   });
 
   return kibanaFormattedCaps.filter(field => {
-    return !['object'].includes(field.type);
+    return !['object', 'nested'].includes(field.type);
   });
 }

src/plugins/kibana_react/public/field_icon/field_icon.tsx

@@ -36,8 +36,8 @@ interface FieldIconProps {
     | 'number'
     | '_source'
     | 'string'
-    | 'nested'
-    | string;
+    | string
+    | 'nested';
   label?: string;
   size?: IconSize;
   useColor?: boolean;

test/api_integration/apis/index_patterns/fields_for_wildcard_route/response.js

@@ -71,14 +71,6 @@ export default function({ getService }) {
               name: 'foo',
               readFromDocValues: true,
             },
-            {
-              aggregatable: false,
-              esTypes: ['nested'],
-              name: 'nestedField',
-              readFromDocValues: false,
-              searchable: false,
-              type: 'nested',
-            },
             {
               aggregatable: false,
               esTypes: ['keyword'],
@@ -161,14 +153,6 @@ export default function({ getService }) {
               name: 'foo',
               readFromDocValues: true,
             },
-            {
-              aggregatable: false,
-              esTypes: ['nested'],
-              name: 'nestedField',
-              readFromDocValues: false,
-              searchable: false,
-              type: 'nested',
-            },
             {
               aggregatable: false,
               esTypes: ['keyword'],