fix(richtext-lexical): internal links render as href="#" in versions view (#15308)

### What

Internal links in Lexical rich text fields render as `href="#"` instead
of proper admin URLs when viewing document versions.

### Why

`LexicalDiffComponent` was passing an empty object to
`LinkDiffHTMLConverterAsync`, so the converter had no way to resolve
internal document references to clickable admin URLs.

### How

Added `internalDocToHref` function to `LexicalDiffComponent` that
handles already-populated doc objects, uses the populate function to
fetch doc data when needed, and formats admin URLs using
`formatAdminURL` utility.

Fixes #15250

Author: PatrikKozak

packages/richtext-lexical/src/field/Diff/index.tsx

@@ -6,9 +6,14 @@ import { FieldDiffContainer, getHTMLDiffComponents } from '@payloadcms/ui/rsc'
 import './index.scss'
 import '../bundled.css'
 
+import { formatAdminURL } from 'payload/shared'
 import React from 'react'
 
-import type { HTMLConvertersFunctionAsync } from '../../features/converters/lexicalToHtml/async/types.js'
+import type {
+  HTMLConvertersFunctionAsync,
+  HTMLPopulateFn,
+} from '../../features/converters/lexicalToHtml/async/types.js'
+import type { SerializedLinkNode } from '../../nodeTypes.js'
 
 import { convertLexicalToHTMLAsync } from '../../features/converters/lexicalToHtml/async/index.js'
 import { getPayloadPopulateFn } from '../../features/converters/utilities/payloadPopulateFn.js'
@@ -31,9 +36,48 @@ export const LexicalDiffComponent: RichTextFieldDiffServerComponent = async (arg
     versionValue: valueTo,
   } = args
 
+  const internalDocToHref = async ({
+    linkNode,
+    populate,
+  }: {
+    linkNode: SerializedLinkNode
+    populate?: HTMLPopulateFn
+  }) => {
+    if (!linkNode.fields.doc) {
+      return '#'
+    }
+
+    const { relationTo, value } = linkNode.fields.doc
+
+    let docId: number | string
+
+    if (typeof value === 'object' && value !== null) {
+      docId = value.id
+    } else if (populate && typeof value !== 'object') {
+      const doc = await populate({
+        id: value,
+        collectionSlug: relationTo,
+      })
+
+      if (!doc || !doc.id) {
+        return '#'
+      }
+
+      docId = doc.id
+    } else {
+      docId = value
+    }
+
+    return formatAdminURL({
+      adminRoute: req.payload.config.routes.admin,
+      path: `/collections/${relationTo}/${docId}`,
+      serverURL: req.payload.config.serverURL,
+    })
+  }
+
   const converters: HTMLConvertersFunctionAsync = ({ defaultConverters }) => ({
     ...defaultConverters,
-    ...LinkDiffHTMLConverterAsync({}),
+    ...LinkDiffHTMLConverterAsync({ internalDocToHref }),
     ...ListItemDiffHTMLConverterAsync,
     ...UploadDiffHTMLConverterAsync({ i18n, req }),
     ...RelationshipDiffHTMLConverterAsync({ i18n, req }),

test/versions/collections/Diff/generateLexicalData.ts

@@ -235,6 +235,51 @@ export function generateLexicalData(args: {
               },
               id: '67d869aa706b36f346ecffd0',
             },
+            {
+              detail: 0,
+              format: 0,
+              mode: 'normal',
+              style: '',
+              text: ' with ',
+              type: 'text',
+              version: 1,
+            },
+            {
+              children: [
+                {
+                  detail: 0,
+                  format: 0,
+                  mode: 'normal',
+                  style: '',
+                  text: args.updated ? 'an updated internal link' : 'an internal link',
+                  type: 'text',
+                  version: 1,
+                },
+              ],
+              direction: 'ltr',
+              format: '',
+              indent: 0,
+              type: 'link',
+              version: 3,
+              fields: {
+                doc: {
+                  relationTo: textCollectionSlug,
+                  value: args.textID,
+                },
+                newTab: false,
+                linkType: 'internal',
+              },
+              id: '67d869aa706b36f346ecffd1',
+            },
+            {
+              detail: 0,
+              format: 0,
+              mode: 'normal',
+              style: '',
+              text: '.',
+              type: 'text',
+              version: 1,
+            },
           ],
           direction: 'ltr',
           format: '',

test/versions/e2e.spec.ts

@@ -2174,6 +2174,27 @@ describe('Versions', () => {
       await expect(richtextWithCustomDiff.locator('p')).toHaveText('Test')
     })
 
+    test('correctly renders internal links in richtext fields', async () => {
+      await navigateToDiffVersionView()
+
+      const richtext = page.locator('[data-field-path="richtext"]')
+
+      const oldDiff = richtext.locator('.html-diff__diff-old')
+      const newDiff = richtext.locator('.html-diff__diff-new')
+
+      const oldInternalLink = oldDiff.locator('a:has-text("an internal link")')
+      const newInternalLink = newDiff.locator('a:has-text("an updated internal link")')
+
+      await expect(oldInternalLink).toHaveCount(1)
+      await expect(newInternalLink).toHaveCount(1)
+
+      await expect(oldInternalLink).not.toHaveAttribute('href', '#')
+      await expect(newInternalLink).not.toHaveAttribute('href', '#')
+
+      await expect(oldInternalLink).toHaveAttribute('href', /\/admin\/collections\/text\/\d+/)
+      await expect(newInternalLink).toHaveAttribute('href', /\/admin\/collections\/text\/\d+/)
+    })
+
     test('correctly renders diff for row fields', async () => {
       await navigateToDiffVersionView()
 

test/versions/payload-types.ts

@@ -1543,6 +1543,6 @@ export interface Auth {
 
 
 declare module 'payload' {
-  // @ts-ignore
+  // @ts-ignore 
   export interface GeneratedTypes extends Config {}
-}
+}