feat: support any depth for relationships in findDistinct (#14090)

Follow up to https://github.com/payloadcms/payload/pull/14026

```ts
// Supported before
const relationResult = await payload.findDistinct({ collection: 'posts', field: 'relation1.title' })
// Supported now
const relationResult = await payload.findDistinct({ collection: 'posts', field: 'relation1.relation2.title' })
const relationResult = await payload.findDistinct({ collection: 'posts', field: 'relation1.relation2.relation3.title' })
```

test/database/getConfig.ts

@@ -54,6 +54,11 @@ export const getConfig: () => Partial<Config> = () => ({
           type: 'text',
           name: 'title',
         },
+        {
+          name: 'simple',
+          type: 'relationship',
+          relationTo: 'simple',
+        },
         {
           type: 'tabs',
           tabs: [
@@ -131,6 +136,11 @@ export const getConfig: () => Partial<Config> = () => ({
           name: 'categoryTitle',
           virtual: 'category.title',
         },
+        {
+          type: 'text',
+          name: 'categorySimpleText',
+          virtual: 'category.simple.text',
+        },
         {
           type: 'relationship',
           relationTo: 'categories',

test/database/int.spec.ts

@@ -1190,6 +1190,114 @@ describe('database', () => {
     ])
   })
 
+  it('should find distinct values with field nested to a 2x relationship', async () => {
+    await payload.delete({ collection: 'posts', where: {} })
+    await payload.delete({ collection: 'categories', where: {} })
+    await payload.delete({ collection: 'simple', where: {} })
+
+    const simple_1 = await payload.create({ collection: 'simple', data: { text: 'simple_1' } })
+    const simple_2 = await payload.create({ collection: 'simple', data: { text: 'simple_2' } })
+    const simple_3 = await payload.create({ collection: 'simple', data: { text: 'simple_3' } })
+
+    const category_1 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_1', simple: simple_1 },
+    })
+    const category_2 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_2', simple: simple_2 },
+    })
+    const category_3 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_3', simple: simple_3 },
+    })
+    const category_4 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_4', simple: simple_3 },
+    })
+
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_1 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_2 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_2 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_2 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_3 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_3 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_3 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_3 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_4 } })
+
+    const res = await payload.findDistinct({
+      collection: 'posts',
+      field: 'category.simple.text',
+    })
+
+    expect(res.values).toEqual([
+      {
+        'category.simple.text': 'simple_1',
+      },
+      {
+        'category.simple.text': 'simple_2',
+      },
+      {
+        'category.simple.text': 'simple_3',
+      },
+    ])
+  })
+
+  it('should find distinct values with virtual field linked to a 2x relationship', async () => {
+    await payload.delete({ collection: 'posts', where: {} })
+    await payload.delete({ collection: 'categories', where: {} })
+    await payload.delete({ collection: 'simple', where: {} })
+
+    const simple_1 = await payload.create({ collection: 'simple', data: { text: 'simple_1' } })
+    const simple_2 = await payload.create({ collection: 'simple', data: { text: 'simple_2' } })
+    const simple_3 = await payload.create({ collection: 'simple', data: { text: 'simple_3' } })
+
+    const category_1 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_1', simple: simple_1 },
+    })
+    const category_2 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_2', simple: simple_2 },
+    })
+    const category_3 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_3', simple: simple_3 },
+    })
+    const category_4 = await payload.create({
+      collection: 'categories',
+      data: { title: 'category_4', simple: simple_3 },
+    })
+
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_1 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_2 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_2 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_2 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_3 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_3 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_3 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_3 } })
+    await payload.create({ collection: 'posts', data: { title: 'post', category: category_4 } })
+
+    const res = await payload.findDistinct({
+      collection: 'posts',
+      field: 'categorySimpleText',
+    })
+
+    expect(res.values).toEqual([
+      {
+        categorySimpleText: 'simple_1',
+      },
+      {
+        categorySimpleText: 'simple_2',
+      },
+      {
+        categorySimpleText: 'simple_3',
+      },
+    ])
+  })
+
   describe('Compound Indexes', () => {
     beforeEach(async () => {
       await payload.delete({ collection: 'compound-indexes', where: {} })

test/database/payload-types.ts

@@ -180,6 +180,7 @@ export interface NoTimeStamp {
 export interface Category {
   id: string;
   title?: string | null;
+  simple?: (string | null) | Simple;
   hideout?: {
     camera1?: {
       time1Image?: (string | null) | Post;
@@ -189,6 +190,17 @@ export interface Category {
   createdAt: string;
   _status?: ('draft' | 'published') | null;
 }
+/**
+ * This interface was referenced by `Config`'s JSON-Schema
+ * via the `definition` "simple".
+ */
+export interface Simple {
+  id: string;
+  text?: string | null;
+  number?: number | null;
+  updatedAt: string;
+  createdAt: string;
+}
 /**
  * This interface was referenced by `Config`'s JSON-Schema
  * via the `definition` "posts".
@@ -198,6 +210,7 @@ export interface Post {
   title: string;
   category?: (string | null) | Category;
   categoryTitle?: string | null;
+  categorySimpleText?: string | null;
   categories?: (string | Category)[] | null;
   categoryPoly?: {
     relationTo: 'categories';
@@ -318,17 +331,6 @@ export interface CategoriesCustomId {
   createdAt: string;
   _status?: ('draft' | 'published') | null;
 }
-/**
- * This interface was referenced by `Config`'s JSON-Schema
- * via the `definition` "simple".
- */
-export interface Simple {
-  id: string;
-  text?: string | null;
-  number?: number | null;
-  updatedAt: string;
-  createdAt: string;
-}
 /**
  * This interface was referenced by `Config`'s JSON-Schema
  * via the `definition` "error-on-unnamed-fields".
@@ -838,6 +840,7 @@ export interface NoTimeStampsSelect<T extends boolean = true> {
  */
 export interface CategoriesSelect<T extends boolean = true> {
   title?: T;
+  simple?: T;
   hideout?:
     | T
     | {
@@ -879,6 +882,7 @@ export interface PostsSelect<T extends boolean = true> {
   title?: T;
   category?: T;
   categoryTitle?: T;
+  categorySimpleText?: T;
   categories?: T;
   categoryPoly?: T;
   categoryPolyMany?: T;