fix(db-postgres): find custom id field from flattened fields for FK type

packages/drizzle/src/schema/traverseFields.ts

@@ -5,6 +5,7 @@ import {
   fieldAffectsData,
   fieldIsVirtual,
   fieldShouldBeLocalized,
+  flattenAllFields,
   optionIsObject,
 } from 'payload/shared'
 import toSnakeCase from 'to-snake-case'
@@ -947,9 +948,9 @@ export const traverseFields = ({
 
           // get the id type of the related collection
           let colType: IDType = isUUIDType(adapter.idType) ? 'uuid' : 'integer'
-          const relatedCollectionCustomID = relationshipConfig.fields.find(
-            (field) => fieldAffectsData(field) && field.name === 'id',
-          )
+          const relatedCollectionCustomID = flattenAllFields({
+            fields: relationshipConfig.fields,
+          }).find((field) => fieldAffectsData(field) && field.name === 'id')
           if (relatedCollectionCustomID?.type === 'number') {
             colType = 'numeric'
           }

test/relationships/config.ts

@@ -9,6 +9,7 @@ import { devUser } from '../credentials.js'
 import {
   chainedRelSlug,
   customIdNumberSlug,
+  customIdRowSlug,
   customIdSlug,
   defaultAccessRelSlug,
   polymorphicRelationshipsSlug,
@@ -128,6 +129,11 @@ export default buildConfigWithDefaults({
           type: 'relationship',
           relationTo: customIdNumberSlug,
         },
+        {
+          name: 'customIdRowRelation',
+          type: 'relationship',
+          relationTo: customIdRowSlug,
+        },
         {
           name: 'filteredRelation',
           type: 'relationship',
@@ -214,6 +220,28 @@ export default buildConfigWithDefaults({
       ],
       versions: false,
     },
+    {
+      // Regression test: custom text id nested inside a row layout field.
+      // The Drizzle schema builder must find the id via flattened fields,
+      // otherwise FK columns default to integer and startup crashes.
+      slug: customIdRowSlug,
+      fields: [
+        {
+          type: 'row',
+          fields: [
+            {
+              name: 'id',
+              type: 'text',
+            },
+            {
+              name: 'name',
+              type: 'text',
+            },
+          ],
+        },
+      ],
+      versions: false,
+    },
     {
       slug: 'screenings',
       fields: [

test/relationships/int.spec.ts

@@ -22,6 +22,7 @@ import { mongooseList } from '../__helpers/shared/isMongoose.js'
 import {
   chainedRelSlug,
   customIdNumberSlug,
+  customIdRowSlug,
   customIdSlug,
   defaultAccessRelSlug,
   polymorphicRelationshipsSlug,
@@ -960,6 +961,19 @@ describe('Relationships', () => {
             .then((res) => res.json())
           expect(customIdNumberRelation).toMatchObject({ id: generatedCustomIdNumber })
         })
+
+        it('should resolve FK type correctly when custom text id is nested in a row field', async () => {
+          // Regression: traverseFields used a shallow find on collection.fields.
+          // A custom text id inside a row/group/collapsible was not detected,
+          // causing FK columns to be integer instead of varchar → startup crash.
+          const rowDoc = await payload.create({
+            collection: customIdRowSlug,
+            data: { id: 'row-custom-id', name: 'Row Custom ID' },
+          })
+          expect(rowDoc.id).toBe('row-custom-id')
+
+          await payload.delete({ collection: customIdRowSlug, id: rowDoc.id })
+        })
       })
 
       describe('depth', () => {

test/relationships/shared.ts

@@ -6,5 +6,6 @@ export const defaultAccessRelSlug = 'strict-access'
 export const chainedRelSlug = 'chained'
 export const customIdSlug = 'custom-id'
 export const customIdNumberSlug = 'custom-id-number'
+export const customIdRowSlug = 'custom-id-row'
 export const polymorphicRelationshipsSlug = 'polymorphic-relationships'
 export const treeSlug = 'tree'