fix: cannot define a join field when the target relationship is nested to a second or higher tab (#12041)

Fixes https://github.com/payloadcms/payload/issues/11720

packages/payload/src/fields/config/sanitizeJoinField.ts

@@ -4,6 +4,8 @@ import type { Config, SanitizedConfig } from '../../config/types.js'
 
 import { APIError } from '../../errors/index.js'
 import { InvalidFieldJoin } from '../../errors/InvalidFieldJoin.js'
+import { flattenAllFields } from '../../utilities/flattenAllFields.js'
+import { getFieldByPath } from '../../utilities/getFieldByPath.js'
 import { traverseFields } from '../../utilities/traverseFields.js'
 import {
   fieldShouldBeLocalized,
@@ -74,86 +76,40 @@ export const sanitizeJoinField = ({
   if (!joinCollection) {
     throw new InvalidFieldJoin(field)
   }
-  let joinRelationship: RelationshipField | UploadField
 
-  const pathSegments = field.on.split('.') // Split the schema path into segments
-  let currentSegmentIndex = 0
-
-  let localized = false
-  // Traverse fields and match based on the schema path
-  traverseFields({
-    callback: ({ field, next, parentIsLocalized }) => {
-      if (!('name' in field) || !field.name) {
-        return
-      }
-      const currentSegment = pathSegments[currentSegmentIndex]
-      // match field on path segments
-      if ('name' in field && field.name === currentSegment) {
-        if (fieldShouldBeLocalized({ field, parentIsLocalized })) {
-          localized = true
-          const fieldIndex = currentSegmentIndex
-
-          join.getForeignPath = ({ locale }) => {
-            return pathSegments.reduce((acc, segment, index) => {
-              let result = `${acc}${segment}`
-
-              if (index === fieldIndex) {
-                result = `${result}.${locale}`
-              }
-
-              if (index !== pathSegments.length - 1) {
-                result = `${result}.`
-              }
-
-              return result
-            }, '')
-          }
-        }
-
-        // Check if this is the last segment in the path
-        if (
-          (currentSegmentIndex === pathSegments.length - 1 &&
-            'type' in field &&
-            field.type === 'relationship') ||
-          field.type === 'upload'
-        ) {
-          joinRelationship = field // Return the matched field
-          next()
-          return true
-        } else {
-          // Move to the next path segment and continue traversal
-          currentSegmentIndex++
-        }
-      } else {
-        // skip fields in non-matching path segments
-        next()
-        return
-      }
-    },
-    config: config as unknown as SanitizedConfig,
-    fields: joinCollection.fields,
-    parentIsLocalized: false,
+  const relationshipField = getFieldByPath({
+    fields: flattenAllFields({ cache: true, fields: joinCollection.fields }),
+    path: field.on,
   })
 
-  if (!joinRelationship) {
+  if (
+    !relationshipField ||
+    (relationshipField.field.type !== 'relationship' && relationshipField.field.type !== 'upload')
+  ) {
     throw new InvalidFieldJoin(join.field)
   }
 
-  if (!joinRelationship.index && !joinRelationship.unique) {
-    joinRelationship.index = true
+  if (relationshipField.pathHasLocalized) {
+    join.getForeignPath = ({ locale }) => {
+      return relationshipField.localizedPath.replace('<locale>', locale)
+    }
+  }
+
+  if (!relationshipField.field.index && !relationshipField.field.unique) {
+    relationshipField.field.index = true
   }
 
   if (validateOnly) {
     return
   }
 
-  join.targetField = joinRelationship
+  join.targetField = relationshipField.field
 
   // override the join field localized property to use whatever the relationship field has
   // or if it's nested to a localized array / blocks / tabs / group
-  field.localized = localized
+  field.localized = relationshipField.field.localized
   // override the join field hasMany property to use whatever the relationship field has
-  field.hasMany = joinRelationship.hasMany
+  field.hasMany = relationshipField.field.hasMany
 
   // @ts-expect-error converting JoinField to FlattenedJoinField to track targetField
   field.targetField = join.targetField

test/joins/collections/Categories.ts

@@ -162,6 +162,12 @@ export const Categories: CollectionConfig = {
         isFiltered: { not_equals: true },
       },
     },
+    {
+      name: 'inTab',
+      type: 'join',
+      collection: postsSlug,
+      on: 'tab.category',
+    },
     {
       name: 'joinWithError',
       type: 'join',

test/joins/collections/Posts.ts

@@ -142,5 +142,34 @@ export const Posts: CollectionConfig = {
         },
       ],
     },
+    {
+      type: 'tabs',
+      tabs: [
+        {
+          name: 'first',
+          fields: [
+            {
+              type: 'text',
+              name: 'tabText',
+            },
+          ],
+        },
+        {
+          name: 'tab',
+          fields: [
+            {
+              type: 'row',
+              fields: [
+                {
+                  name: 'category',
+                  type: 'relationship',
+                  relationTo: categoriesSlug,
+                },
+              ],
+            },
+          ],
+        },
+      ],
+    },
   ],
 }

test/joins/payload-types.ts

@@ -113,6 +113,7 @@ export interface Config {
       localizedPolymorphic: 'posts';
       localizedPolymorphics: 'posts';
       filtered: 'posts';
+      inTab: 'posts';
       joinWithError: 'posts';
       hiddenPosts: 'hidden-posts';
       singulars: 'singular';
@@ -316,6 +317,12 @@ export interface Post {
         blockType: 'block';
       }[]
     | null;
+  first?: {
+    tabText?: string | null;
+  };
+  tab?: {
+    category?: (string | null) | Category;
+  };
   updatedAt: string;
   createdAt: string;
 }
@@ -429,6 +436,11 @@ export interface Category {
     hasNextPage?: boolean;
     totalDocs?: number;
   };
+  inTab?: {
+    docs?: (string | Post)[];
+    hasNextPage?: boolean;
+    totalDocs?: number;
+  };
   joinWithError?: {
     docs?: (string | Post)[];
     hasNextPage?: boolean;
@@ -935,6 +947,16 @@ export interface PostsSelect<T extends boolean = true> {
               blockName?: T;
             };
       };
+  first?:
+    | T
+    | {
+        tabText?: T;
+      };
+  tab?:
+    | T
+    | {
+        category?: T;
+      };
   updatedAt?: T;
   createdAt?: T;
 }
@@ -963,6 +985,7 @@ export interface CategoriesSelect<T extends boolean = true> {
   localizedPolymorphics?: T;
   singulars?: T;
   filtered?: T;
+  inTab?: T;
   joinWithError?: T;
   enableErrorOnJoin?: T;
   updatedAt?: T;