fix: findDistinct with polymorphic relationships (#13875)

Fixes `findDistinct` with polymorphic relationships and also fixes a bug
from https://github.com/payloadcms/payload/pull/13840 when
`findDistinct` didn't work properly for `hasMany` relationships in
mongodb if `sort` is the same as `field`

---------

Co-authored-by: Patrik Kozak <35232443+PatrikKozak@users.noreply.github.com>

packages/db-mongodb/src/findDistinct.ts

@@ -56,22 +56,26 @@ export const findDistinct: FindDistinct = async function (this: MongooseAdapter,
   const sortProperty = Object.keys(sort)[0]! // assert because buildSortParam always returns at least 1 key.
   const sortDirection = sort[sortProperty] === 'asc' ? 1 : -1
 
-  let $unwind: string = ''
-  let $group: any
+  let $unwind: any = ''
+  let $group: any = null
   if (
     isHasManyValue &&
     sortAggregation.length &&
     sortAggregation[0] &&
     '$lookup' in sortAggregation[0]
   ) {
-    $unwind = `$${sortAggregation[0].$lookup.as}`
+    $unwind = { path: `$${sortAggregation[0].$lookup.as}`, preserveNullAndEmptyArrays: true }
     $group = {
       _id: {
         _field: `$${sortAggregation[0].$lookup.as}._id`,
         _sort: `$${sortProperty}`,
       },
     }
-  } else {
+  } else if (isHasManyValue) {
+    $unwind = { path: `$${args.field}`, preserveNullAndEmptyArrays: true }
+  }
+
+  if (!$group) {
     $group = {
       _id: {
         _field: `$${fieldPath}`,

packages/drizzle/src/findDistinct.ts

@@ -1,5 +1,4 @@
-import type { FindDistinct, SanitizedCollectionConfig } from 'payload'
-
+import { type FindDistinct, getFieldByPath, type SanitizedCollectionConfig } from 'payload'
 import toSnakeCase from 'to-snake-case'
 
 import type { DrizzleAdapter, GenericColumn } from './types.js'
@@ -57,12 +56,32 @@ export const findDistinct: FindDistinct = async function (this: DrizzleAdapter,
     },
     selectFields: {
       _selected: selectFields['_selected'],
-      ...(orderBy[0].column === selectFields['_selected'] ? {} : { _order: orderBy[0].column }),
+      ...(orderBy.length &&
+        (orderBy[0].column === selectFields['_selected'] ? {} : { _order: orderBy[0]?.column })),
     } as Record<string, GenericColumn>,
     tableName,
     where,
   })
 
+  const field = getFieldByPath({
+    fields: collectionConfig.flattenedFields,
+    path: args.field,
+  })?.field
+
+  if (field && 'relationTo' in field && Array.isArray(field.relationTo)) {
+    for (const row of selectDistinctResult as any) {
+      const json = JSON.parse(row._selected)
+      const relationTo = Object.keys(json).find((each) => Boolean(json[each]))
+      const value = json[relationTo]
+
+      if (!value) {
+        row._selected = null
+      } else {
+        row._selected = { relationTo, value }
+      }
+    }
+  }
+
   const values = selectDistinctResult.map((each) => ({
     [args.field]: (each as Record<string, any>)._selected,
   }))

packages/drizzle/src/queries/getTableColumnFromPath.ts

@@ -19,6 +19,8 @@ import type { DrizzleAdapter, GenericColumn } from '../types.js'
 import type { BuildQueryJoinAliases } from './buildQuery.js'
 
 import { isPolymorphicRelationship } from '../utilities/isPolymorphicRelationship.js'
+import { jsonBuildObject } from '../utilities/json.js'
+import { DistinctSymbol } from '../utilities/rawConstraint.js'
 import { resolveBlockTableName } from '../utilities/validateExistingBlockIsIdentical.js'
 import { addJoinTable } from './addJoinTable.js'
 import { getTableAlias } from './getTableAlias.js'
@@ -722,6 +724,28 @@ export const getTableColumnFromPath = ({
               rawColumn: sql.raw(`"${aliasRelationshipTableName}"."${relationTableName}_id"`),
               table: aliasRelationshipTable,
             }
+          } else if (value === DistinctSymbol) {
+            const obj: Record<string, SQL> = {}
+
+            field.relationTo.forEach((relationTo) => {
+              const relationTableName = adapter.tableNameMap.get(
+                toSnakeCase(adapter.payload.collections[relationTo].config.slug),
+              )
+
+              obj[relationTo] = sql.raw(`"${aliasRelationshipTableName}"."${relationTableName}_id"`)
+            })
+
+            let rawColumn = jsonBuildObject(adapter, obj)
+            if (adapter.name === 'postgres') {
+              rawColumn = sql`${rawColumn}::text`
+            }
+
+            return {
+              constraints,
+              field,
+              rawColumn,
+              table: aliasRelationshipTable,
+            }
           } else {
             throw new APIError('Not supported')
           }

test/database/getConfig.ts

@@ -132,6 +132,17 @@ export const getConfig: () => Partial<Config> = () => ({
           hasMany: true,
           name: 'categories',
         },
+        {
+          type: 'relationship',
+          relationTo: ['categories'],
+          name: 'categoryPoly',
+        },
+        {
+          type: 'relationship',
+          relationTo: ['categories'],
+          hasMany: true,
+          name: 'categoryPolyMany',
+        },
         {
           type: 'relationship',
           relationTo: 'categories-custom-id',

test/database/int.spec.ts

@@ -923,6 +923,183 @@ describe('database', () => {
       expect(fromRes.categories.title).toBe(title)
       expect(fromRes.categories.id).toBe(id)
     }
+
+    // Non-consistent sorting by ID
+    // eslint-disable-next-line jest/no-conditional-in-test
+    if (process.env.PAYLOAD_DATABASE?.includes('uuid')) {
+      return
+    }
+
+    const resultDepth1NoSort = await payload.findDistinct({
+      depth: 1,
+      collection: 'posts',
+      field: 'categories',
+    })
+
+    for (let i = 0; i < resultDepth1NoSort.values.length; i++) {
+      const fromRes = resultDepth1NoSort.values[i] as any
+      const id = categoriesIDS[i].categories as any
+      const title = categories[i]?.title
+      expect(fromRes.categories.title).toBe(title)
+      expect(fromRes.categories.id).toBe(id)
+    }
+  })
+
+  it('should populate distinct relationships of polymorphic when depth>0', async () => {
+    await payload.delete({ collection: 'posts', where: {} })
+    await payload.delete({ collection: 'categories', where: {} })
+
+    const category_1 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_1' },
+    })
+    const category_2 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_2' },
+    })
+    const category_3 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_3' },
+    })
+
+    const post_1 = await payload.create({
+      collection: 'posts',
+      data: { title: 'post_1', categoryPoly: { relationTo: 'categories', value: category_1.id } },
+    })
+    const post_2 = await payload.create({
+      collection: 'posts',
+      data: { title: 'post_2', categoryPoly: { relationTo: 'categories', value: category_1.id } },
+    })
+    const post_3 = await payload.create({
+      collection: 'posts',
+      data: { title: 'post_3', categoryPoly: { relationTo: 'categories', value: category_2.id } },
+    })
+    const post_4 = await payload.create({
+      collection: 'posts',
+      data: { title: 'post_4', categoryPoly: { relationTo: 'categories', value: category_3.id } },
+    })
+    const post_5 = await payload.create({
+      collection: 'posts',
+      data: { title: 'post_5', categoryPoly: { relationTo: 'categories', value: category_3.id } },
+    })
+
+    const result = await payload.findDistinct({
+      depth: 0,
+      collection: 'posts',
+      field: 'categoryPoly',
+    })
+
+    expect(result.values).toHaveLength(3)
+    expect(
+      result.values.some(
+        (v) =>
+          v.categoryPoly?.relationTo === 'categories' && v.categoryPoly.value === category_1.id,
+      ),
+    ).toBe(true)
+    expect(
+      result.values.some(
+        (v) =>
+          v.categoryPoly?.relationTo === 'categories' && v.categoryPoly.value === category_2.id,
+      ),
+    ).toBe(true)
+    expect(
+      result.values.some(
+        (v) =>
+          v.categoryPoly?.relationTo === 'categories' && v.categoryPoly.value === category_3.id,
+      ),
+    ).toBe(true)
+  })
+
+  it('should populate distinct relationships of hasMany polymorphic when depth>0', async () => {
+    await payload.delete({ collection: 'posts', where: {} })
+    await payload.delete({ collection: 'categories', where: {} })
+
+    const category_1 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_1' },
+    })
+    const category_2 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_2' },
+    })
+    const category_3 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_3' },
+    })
+
+    const post_1 = await payload.create({
+      collection: 'posts',
+      data: {
+        title: 'post_1',
+        categoryPolyMany: [{ relationTo: 'categories', value: category_1.id }],
+      },
+    })
+    const post_2 = await payload.create({
+      collection: 'posts',
+      data: {
+        title: 'post_2',
+        categoryPolyMany: [{ relationTo: 'categories', value: category_1.id }],
+      },
+    })
+    const post_3 = await payload.create({
+      collection: 'posts',
+      data: {
+        title: 'post_3',
+        categoryPolyMany: [{ relationTo: 'categories', value: category_2.id }],
+      },
+    })
+    const post_4 = await payload.create({
+      collection: 'posts',
+      data: {
+        title: 'post_4',
+        categoryPolyMany: [{ relationTo: 'categories', value: category_3.id }],
+      },
+    })
+    const post_5 = await payload.create({
+      collection: 'posts',
+      data: {
+        title: 'post_5',
+        categoryPolyMany: [{ relationTo: 'categories', value: category_3.id }],
+      },
+    })
+
+    const post_6 = await payload.create({
+      collection: 'posts',
+      data: {
+        title: 'post_6',
+        categoryPolyMany: null,
+      },
+    })
+
+    const result = await payload.findDistinct({
+      depth: 0,
+      collection: 'posts',
+      field: 'categoryPolyMany',
+    })
+
+    expect(result.values).toHaveLength(4)
+    expect(
+      result.values.some(
+        (v) =>
+          v.categoryPolyMany?.relationTo === 'categories' &&
+          v.categoryPolyMany.value === category_1.id,
+      ),
+    ).toBe(true)
+    expect(
+      result.values.some(
+        (v) =>
+          v.categoryPolyMany?.relationTo === 'categories' &&
+          v.categoryPolyMany.value === category_2.id,
+      ),
+    ).toBe(true)
+    expect(
+      result.values.some(
+        (v) =>
+          v.categoryPolyMany?.relationTo === 'categories' &&
+          v.categoryPolyMany.value === category_3.id,
+      ),
+    ).toBe(true)
+    expect(result.values.some((v) => v.categoryPolyMany === null)).toBe(true)
   })
 
   describe('Compound Indexes', () => {

test/database/payload-types.ts

@@ -198,6 +198,16 @@ export interface Post {
   title: string;
   category?: (string | null) | Category;
   categories?: (string | Category)[] | null;
+  categoryPoly?: {
+    relationTo: 'categories';
+    value: string | Category;
+  } | null;
+  categoryPolyMany?:
+    | {
+        relationTo: 'categories';
+        value: string | Category;
+      }[]
+    | null;
   categoryCustomID?: (number | null) | CategoriesCustomId;
   localized?: string | null;
   text?: string | null;
@@ -827,6 +837,8 @@ export interface PostsSelect<T extends boolean = true> {
   title?: T;
   category?: T;
   categories?: T;
+  categoryPoly?: T;
+  categoryPolyMany?: T;
   categoryCustomID?: T;
   localized?: T;
   text?: T;