🐛 Fixed newsletter post duplication (#17103)

closes https://github.com/TryGhost/Team/issues/3521

When duplicating a newsletter (email only post) some of the fields
relating to the newsletter (i.e `newsletter_id`) were being erroneously
copied over. Upon publishing this made the post appear as if it was an
email only post that had been sent to subscribers when it actually had
not

ghost/posts-service/lib/PostsService.js

@@ -3,7 +3,7 @@ const {BadRequestError} = require('@tryghost/errors');
 const tpl = require('@tryghost/tpl');
 const errors = require('@tryghost/errors');
 const ObjectId = require('bson-objectid').default;
-const omit = require('lodash/omit');
+const pick = require('lodash/pick');
 
 const messages = {
     invalidVisibilityFilter: 'Invalid visibility filter.',
@@ -512,21 +512,24 @@ class PostsService {
             status: 'all'
         }, frame.options);
 
-        const newPostData = omit(
+        const newPostData = pick(
             existingPost.attributes,
             [
-                'id',
-                'uuid',
-                'slug',
-                'comment_id',
-                'created_at',
-                'created_by',
-                'updated_at',
-                'updated_by',
-                'published_at',
-                'published_by',
-                'canonical_url',
-                'count__clicks'
+                'title',
+                'mobiledoc',
+                'lexical',
+                'html',
+                'plaintext',
+                'feature_image',
+                'featured',
+                'type',
+                'locale',
+                'visibility',
+                'email_recipient_filter',
+                'custom_excerpt',
+                'codeinjection_head',
+                'codeinjection_foot',
+                'custom_template'
             ]
         );
 
@@ -540,11 +543,20 @@ class PostsService {
         const existingPostMeta = existingPost.related('posts_meta');
 
         if (existingPostMeta.isNew() === false) {
-            newPostData.posts_meta = omit(
+            newPostData.posts_meta = pick(
                 existingPostMeta.attributes,
                 [
-                    'id',
-                    'post_id'
+                    'og_image',
+                    'og_title',
+                    'og_description',
+                    'twitter_image',
+                    'twitter_title',
+                    'twitter_description',
+                    'meta_title',
+                    'meta_description',
+                    'frontmatter',
+                    'feature_image_alt',
+                    'feature_image_caption'
                 ]
             );
         }

ghost/posts-service/test/PostsService.test.js

@@ -71,7 +71,8 @@ describe('Posts Service', function () {
                     id: POST_ID,
                     title: 'Test Post',
                     slug: 'test-post',
-                    status: 'published'
+                    status: 'published',
+                    newsletter_id: 'abc123'
                 },
                 related: sinon.stub()
             };
@@ -217,7 +218,9 @@ describe('Posts Service', function () {
                 attributes: {
                     post_id: POST_ID,
                     meta_title: 'Test Post',
-                    meta_description: 'Test Post Description'
+                    meta_description: 'Test Post Description',
+                    email_only: 1,
+                    email_subject: 'Test Email Subject'
                 },
                 isNew: () => false
             };