fix: support hasMany: true relationships in findDistinct (#13840)

Previously, the `findDistinct` operation didn't work correctly for
relationships with `hasMany: true`. This PR fixes it.

packages/db-mongodb/src/findDistinct.ts

@@ -48,28 +48,56 @@ export const findDistinct: FindDistinct = async function (this: MongooseAdapter,
     fieldPath = fieldPathResult.localizedPath.replace('<locale>', args.locale)
   }
 
+  const isHasManyValue =
+    fieldPathResult && 'hasMany' in fieldPathResult.field && fieldPathResult.field.hasMany
+
   const page = args.page || 1
 
   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 $group: any
+  if (
+    isHasManyValue &&
+    sortAggregation.length &&
+    sortAggregation[0] &&
+    '$lookup' in sortAggregation[0]
+  ) {
+    $unwind = `$${sortAggregation[0].$lookup.as}`
+    $group = {
+      _id: {
+        _field: `$${sortAggregation[0].$lookup.as}._id`,
+        _sort: `$${sortProperty}`,
+      },
+    }
+  } else {
+    $group = {
+      _id: {
+        _field: `$${fieldPath}`,
+        ...(sortProperty === fieldPath
+          ? {}
+          : {
+              _sort: `$${sortProperty}`,
+            }),
+      },
+    }
+  }
+
   const pipeline: PipelineStage[] = [
     {
       $match: query,
     },
     ...(sortAggregation.length > 0 ? sortAggregation : []),
-
+    ...($unwind
+      ? [
+          {
+            $unwind,
+          },
+        ]
+      : []),
     {
-      $group: {
-        _id: {
-          _field: `$${fieldPath}`,
-          ...(sortProperty === fieldPath
-            ? {}
-            : {
-                _sort: `$${sortProperty}`,
-              }),
-        },
-      },
+      $group,
     },
     {
       $sort: {

packages/drizzle/src/queries/getTableColumnFromPath.ts

@@ -1,4 +1,4 @@
-import type { SQL } from 'drizzle-orm'
+import type { SQL, Table } from 'drizzle-orm'
 import type { SQLiteTableWithColumns } from 'drizzle-orm/sqlite-core'
 import type {
   FlattenedBlock,
@@ -8,7 +8,7 @@ import type {
   TextField,
 } from 'payload'
 
-import { and, eq, like, sql } from 'drizzle-orm'
+import { and, eq, getTableName, like, sql } from 'drizzle-orm'
 import { type PgTableWithColumns } from 'drizzle-orm/pg-core'
 import { APIError, getFieldByPath } from 'payload'
 import { fieldShouldBeLocalized, tabHasName } from 'payload/shared'
@@ -537,13 +537,22 @@ export const getTableColumnFromPath = ({
         if (Array.isArray(field.relationTo) || field.hasMany) {
           let relationshipFields: FlattenedField[]
           const relationTableName = `${rootTableName}${adapter.relationshipsSuffix}`
-          const {
-            newAliasTable: aliasRelationshipTable,
-            newAliasTableName: aliasRelationshipTableName,
-          } = getTableAlias({
-            adapter,
-            tableName: relationTableName,
-          })
+
+          const existingJoin = joins.find((e) => e.queryPath === `${constraintPath}.${field.name}`)
+
+          let aliasRelationshipTable: PgTableWithColumns<any> | SQLiteTableWithColumns<any>
+          let aliasRelationshipTableName: string
+          if (existingJoin) {
+            aliasRelationshipTable = existingJoin.table
+            aliasRelationshipTableName = getTableName(existingJoin.table)
+          } else {
+            const res = getTableAlias({
+              adapter,
+              tableName: relationTableName,
+            })
+            aliasRelationshipTable = res.newAliasTable
+            aliasRelationshipTableName = res.newAliasTableName
+          }
 
           if (selectLocale && isFieldLocalized && adapter.payload.config.localization) {
             selectFields._locale = aliasRelationshipTable.locale

packages/payload/src/collections/operations/findDistinct.ts

@@ -155,6 +155,10 @@ export const findDistinctOperation = async (
       args.depth
     ) {
       const populationPromises: Promise<void>[] = []
+      const sanitizedField = { ...fieldResult.field }
+      if (fieldResult.field.hasMany) {
+        sanitizedField.hasMany = false
+      }
       for (const doc of result.values) {
         populationPromises.push(
           relationshipPopulationPromise({
@@ -162,7 +166,7 @@ export const findDistinctOperation = async (
             depth: args.depth,
             draft: false,
             fallbackLocale: req.fallbackLocale || null,
-            field: fieldResult.field,
+            field: sanitizedField,
             locale: req.locale || null,
             overrideAccess: args.overrideAccess ?? true,
             parentIsLocalized: false,

test/database/getConfig.ts

@@ -126,6 +126,12 @@ export const getConfig: () => Partial<Config> = () => ({
           relationTo: 'categories',
           name: 'category',
         },
+        {
+          type: 'relationship',
+          relationTo: 'categories',
+          hasMany: true,
+          name: 'categories',
+        },
         {
           type: 'relationship',
           relationTo: 'categories-custom-id',

test/database/int.spec.ts

@@ -856,6 +856,75 @@ describe('database', () => {
     }
   })
 
+  it('should populate distinct relationships of hasMany: true when depth>0', async () => {
+    await payload.delete({ collection: 'posts', where: {} })
+    await payload.delete({ collection: 'categories', where: {} })
+
+    const categories = ['category-1', 'category-2', 'category-3', 'category-4'].map((title) => ({
+      title,
+    }))
+
+    const categoriesIDS: { categories: string }[] = []
+
+    for (const { title } of categories) {
+      const doc = await payload.create({ collection: 'categories', data: { title } })
+      categoriesIDS.push({ categories: doc.id })
+    }
+
+    await payload.create({
+      collection: 'posts',
+      data: {
+        title: '1',
+        categories: [categoriesIDS[0]?.categories, categoriesIDS[1]?.categories],
+      },
+    })
+
+    await payload.create({
+      collection: 'posts',
+      data: {
+        title: '2',
+        categories: [
+          categoriesIDS[0]?.categories,
+          categoriesIDS[2]?.categories,
+          categoriesIDS[3]?.categories,
+        ],
+      },
+    })
+
+    await payload.create({
+      collection: 'posts',
+      data: {
+        title: '3',
+        categories: [
+          categoriesIDS[0]?.categories,
+          categoriesIDS[3]?.categories,
+          categoriesIDS[1]?.categories,
+        ],
+      },
+    })
+
+    const resultDepth0 = await payload.findDistinct({
+      collection: 'posts',
+      sort: 'categories.title',
+      field: 'categories',
+    })
+    expect(resultDepth0.values).toStrictEqual(categoriesIDS)
+    const resultDepth1 = await payload.findDistinct({
+      depth: 1,
+      collection: 'posts',
+      field: 'categories',
+      sort: 'categories.title',
+    })
+
+    for (let i = 0; i < resultDepth1.values.length; i++) {
+      const fromRes = resultDepth1.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)
+    }
+  })
+
   describe('Compound Indexes', () => {
     beforeEach(async () => {
       await payload.delete({ collection: 'compound-indexes', where: {} })

test/database/payload-types.ts

@@ -197,6 +197,7 @@ export interface Post {
   id: string;
   title: string;
   category?: (string | null) | Category;
+  categories?: (string | Category)[] | null;
   categoryCustomID?: (number | null) | CategoriesCustomId;
   localized?: string | null;
   text?: string | null;
@@ -822,6 +823,7 @@ export interface CategoriesCustomIdSelect<T extends boolean = true> {
 export interface PostsSelect<T extends boolean = true> {
   title?: T;
   category?: T;
+  categories?: T;
   categoryCustomID?: T;
   localized?: T;
   text?: T;