fix(db-mongodb): localization transforms on nested localized fields (#14600)

Fixes an issue where nested `localized: true` fields were not adhering
to the correct data shape if a parent was already localized. This change
works with the `compatibility.allowLocalizedWithinLocalized` flag set
and not set. Before it would only work if you had the compatibility flag
set to true, which is not the default.

The issue surfaces when querying with `locale: "all"`.

Example:
```ts
fields: [{
  name: 'localizedBlocks',
  type: 'blocks',
  blocks: [
    {
      slug: 'nestedBlock',
      fields: [
        {
          name: 'nestedArray',
          type: 'array',
          fields: [
            {
              name: 'item',
              type: 'text',
            },
          ],
          localized: true, // <-- this
        },
      ],
    },
  ],
  localized: true, // <-- and this
}],
```

When transforming the outgoing data it would not include everything
because it would incorrectly attempt to access data by locale on nested
data instead of just the field name.


#### Before (incorrect)
```ts
localizedBlocks: {
  en: [
    {
      blockType: 'nestedBlock',
      nestedArray: [] // <-- missing
    }
  ]
}
```

#### After (correct)
```ts
localizedBlocks: {
  en: [
    {
      blockType: 'nestedBlock',
      nestedArray: [ // <-- included
        {
          id: '69162b9cecdd3484a55e196b',
          item: 'EN Nested',
        },
      ],
    },
  ]
}
```

Author: JarrodMFlesch

packages/db-mongodb/src/utilities/transform.ts

@@ -305,11 +305,13 @@ const stripFields = ({
   config,
   data,
   fields,
+  parentIsLocalized = false,
   reservedKeys = [],
 }: {
   config: SanitizedConfig
   data: any
   fields: FlattenedField[]
+  parentIsLocalized?: boolean
   reservedKeys?: string[]
 }) => {
   for (const k in data) {
@@ -325,12 +327,14 @@ const stripFields = ({
       continue
     }
 
+    const shouldLocalizeField = fieldShouldBeLocalized({ field, parentIsLocalized })
+
     if (field.type === 'blocks') {
       reservedKeys.push('blockType')
     }
 
     if ('flattenedFields' in field || 'blocks' in field) {
-      if (field.localized && config.localization) {
+      if (shouldLocalizeField && config.localization) {
         for (const localeKey in fieldData) {
           if (!config.localization.localeCodes.some((code) => code === localeKey)) {
             delete fieldData[localeKey]
@@ -389,7 +393,13 @@ const stripFields = ({
                 continue
               }
 
-              stripFields({ config, data, fields, reservedKeys })
+              stripFields({
+                config,
+                data,
+                fields,
+                parentIsLocalized: parentIsLocalized || field.localized,
+                reservedKeys,
+              })
             }
 
             if (hasNull) {
@@ -398,7 +408,13 @@ const stripFields = ({
 
             continue
           } else {
-            stripFields({ config, data: localeData, fields: field.flattenedFields, reservedKeys })
+            stripFields({
+              config,
+              data: localeData,
+              fields: field.flattenedFields,
+              parentIsLocalized: parentIsLocalized || field.localized,
+              reservedKeys,
+            })
           }
         }
         continue
@@ -451,7 +467,13 @@ const stripFields = ({
             continue
           }
 
-          stripFields({ config, data, fields, reservedKeys })
+          stripFields({
+            config,
+            data,
+            fields,
+            parentIsLocalized: parentIsLocalized || field.localized,
+            reservedKeys,
+          })
         }
 
         if (hasNull) {
@@ -460,7 +482,13 @@ const stripFields = ({
 
         continue
       } else {
-        stripFields({ config, data: fieldData, fields: field.flattenedFields, reservedKeys })
+        stripFields({
+          config,
+          data: fieldData,
+          fields: field.flattenedFields,
+          parentIsLocalized: parentIsLocalized || field.localized,
+          reservedKeys,
+        })
       }
     }
   }
@@ -524,6 +552,7 @@ export const transform = ({
         config,
         data,
         fields: flattenAllFields({ cache: true, fields }),
+        parentIsLocalized: false,
         reservedKeys: ['id', 'globalType'],
       })
     }

test/localization/collections/AllFields/index.ts

@@ -0,0 +1,238 @@
+import type { CollectionConfig } from 'payload'
+
+import { allFieldsLocalizedSlug } from '../../shared.js'
+
+export const AllFieldsLocalized: CollectionConfig = {
+  slug: allFieldsLocalizedSlug,
+  fields: [
+    // Simple localized fields
+    {
+      name: 'text',
+      type: 'text',
+      localized: true,
+    },
+    {
+      name: 'textarea',
+      type: 'textarea',
+      localized: true,
+    },
+    {
+      name: 'number',
+      type: 'number',
+      localized: true,
+    },
+    {
+      name: 'email',
+      type: 'email',
+      localized: true,
+    },
+    {
+      name: 'code',
+      type: 'code',
+      localized: true,
+    },
+    {
+      name: 'json',
+      type: 'json',
+      localized: true,
+    },
+    {
+      name: 'select',
+      type: 'select',
+      localized: true,
+      options: ['option1', 'option2', 'option3'],
+    },
+    {
+      name: 'radio',
+      type: 'radio',
+      localized: true,
+      options: ['radio1', 'radio2'],
+    },
+    {
+      name: 'checkbox',
+      type: 'checkbox',
+      localized: true,
+    },
+    {
+      name: 'date',
+      type: 'date',
+      localized: true,
+    },
+
+    // Localized group with localized children
+    {
+      name: 'localizedGroup',
+      type: 'group',
+      fields: [
+        {
+          name: 'title',
+          type: 'text',
+          localized: true,
+        },
+        {
+          name: 'description',
+          type: 'textarea',
+          localized: true,
+        },
+      ],
+      localized: true,
+    },
+
+    // Non-localized group with localized children
+    {
+      name: 'nonLocalizedGroup',
+      type: 'group',
+      fields: [
+        {
+          name: 'localizedText',
+          type: 'text',
+          localized: true,
+        },
+        {
+          name: 'nonLocalizedText',
+          type: 'text',
+        },
+      ],
+    },
+
+    // Localized array with localized children
+    {
+      name: 'localizedArray',
+      type: 'array',
+      fields: [
+        {
+          name: 'item',
+          type: 'text',
+          localized: true,
+        },
+      ],
+      localized: true,
+    },
+
+    // Non-localized array with localized children
+    {
+      name: 'nonLocalizedArray',
+      type: 'array',
+      fields: [
+        {
+          name: 'localizedItem',
+          type: 'text',
+          localized: true,
+        },
+      ],
+    },
+
+    // Localized blocks with nested localized fields
+    {
+      name: 'localizedBlocks',
+      type: 'blocks',
+      blocks: [
+        {
+          slug: 'localizedTextBlock',
+          fields: [
+            {
+              name: 'text',
+              type: 'text',
+              localized: true,
+            },
+          ],
+        },
+        {
+          slug: 'nestedBlock',
+          fields: [
+            {
+              name: 'nestedArray',
+              type: 'array',
+              fields: [
+                {
+                  name: 'item',
+                  type: 'text',
+                },
+              ],
+              localized: true,
+            },
+          ],
+        },
+      ],
+      localized: true,
+    },
+
+    // Named tabs with localized tab
+    {
+      type: 'tabs',
+      tabs: [
+        {
+          name: 'localizedTab',
+          fields: [
+            {
+              name: 'tabText',
+              type: 'text',
+              localized: true,
+            },
+          ],
+          label: 'Localized Tab',
+          localized: true,
+        },
+        {
+          name: 'nonLocalizedTab',
+          fields: [
+            {
+              name: 'localizedInNonLocalizedTab',
+              type: 'text',
+              localized: true,
+            },
+          ],
+          label: 'Non-Localized Tab',
+        },
+      ],
+    },
+
+    // Unnamed tab (passes through)
+    {
+      type: 'tabs',
+      tabs: [
+        {
+          fields: [
+            {
+              name: 'unnamedTabLocalizedText',
+              type: 'text',
+              localized: true,
+            },
+          ],
+          label: 'Unnamed Tab',
+        },
+      ],
+    },
+
+    // Deeply nested: localized group > non-localized group > localized array
+    {
+      name: 'g1',
+      type: 'group',
+      label: 'Deeply Nested Group',
+      fields: [
+        {
+          name: 'g2',
+          type: 'group',
+          fields: [
+            {
+              name: 'g2a1',
+              type: 'array',
+              fields: [
+                {
+                  name: 'text',
+                  type: 'text',
+                  localized: true,
+                },
+              ],
+              localized: true,
+            },
+          ],
+        },
+      ],
+      localized: true,
+    },
+  ],
+  versions: {
+    drafts: true,
+  },
+}

test/localization/config.ts

@@ -8,6 +8,7 @@ import type { LocalizedPost } from './payload-types.js'
 
 import { buildConfigWithDefaults } from '../buildConfigWithDefaults.js'
 import { devUser } from '../credentials.js'
+import { AllFieldsLocalized } from './collections/AllFields/index.js'
 import { ArrayCollection } from './collections/Array/index.js'
 import { ArrayWithFallbackCollection } from './collections/ArrayWithFallback/index.js'
 import { BlocksCollection } from './collections/Blocks/index.js'
@@ -68,6 +69,7 @@ export default buildConfigWithDefaults({
     NestedFields,
     LocalizedDrafts,
     LocalizedDateFields,
+    AllFieldsLocalized,
     {
       admin: {
         listSearchableFields: 'name',