FIX: Show membership requests link just for group owners. (#7543)

app/controllers/groups_controller.rb

@@ -443,20 +443,12 @@ class GroupsController < ApplicationController
         .pluck("users.username")
     )
 
-    raw = <<~EOF
-      #{reason}
-
-      ---
-      <a href="#{Discourse.base_uri}/g/#{group.name}/requests">
-        #{I18n.t('groups.request_membership_pm.handle')}
-      </a>
-    EOF
-
     post = PostCreator.new(current_user,
       title: I18n.t('groups.request_membership_pm.title', group_name: group.name),
-      raw: raw,
+      raw: params[:reason],
       archetype: Archetype.private_message,
       target_usernames: usernames.join(','),
+      custom_fields: { requested_group_id: group.id },
       skip_validations: true
     ).create!
 

app/serializers/basic_post_serializer.rb

@@ -38,7 +38,27 @@ class BasicPostSerializer < ApplicationSerializer
         I18n.t('flagging.user_must_edit')
       end
     else
-      object.filter_quotes(@parent_post)
+      cooked = object.filter_quotes(@parent_post)
+
+      if scope&.user
+        group = Group
+          .joins('JOIN group_users ON groups.id = group_users.group_id')
+          .find_by(
+            id: object.custom_fields['requested_group_id'].to_i,
+            group_users: { user_id: scope.user.id, owner: true }
+          )
+
+        if group
+          cooked << <<~EOF
+            <hr />
+            <a href="#{Discourse.base_uri}/g/#{group.name}/requests">
+              #{I18n.t('groups.request_membership_pm.handle')}
+            </a>
+          EOF
+        end
+      end
+
+      cooked
     end
   end