Setting to automatically lock posts when edited by staff

config/locales/server.en.yml

@@ -995,6 +995,7 @@ en:
     download_remote_images_max_days_old: "Don't download remote images for posts that are more than n days old."
     disabled_image_download_domains: "Remote images will never be downloaded from these domains. Pipe-delimited list."
     editing_grace_period: "For (n) seconds after posting, editing will not create a new version in the post history."
+    staff_edit_locks_post: "Posts will be locked from editing if they are edited by staff members"
     post_edit_time_limit: "The author can edit or delete their post for (n) minutes after posting. Set to 0 for forever."
     edit_history_visible_to_public: "Allow everyone to see previous versions of an edited post. When disabled, only staff members can view."
     delete_removed_posts_after: "Posts removed by the author will be automatically deleted after (n) hours. If set to 0, posts will be deleted immediately."

config/site_settings.yml

@@ -514,6 +514,7 @@ posting:
     client: true
     validator: "EnablePrivateEmailMessagesValidator"
   editing_grace_period: 300
+  staff_edit_locks_post: false
   post_edit_time_limit:
     default: 86400
     max: 525600

lib/post_revisor.rb

@@ -1,4 +1,5 @@
 require "edit_rate_limiter"
+require 'post_locker'
 
 class PostRevisor
 
@@ -163,6 +164,13 @@ class PostRevisor
       advance_draft_sequence
     end
 
+    # Lock the post by default if the appropriate setting is true
+    if SiteSetting.staff_edit_locks_post? &&
+        @editor.staff? &&
+        !@post.user.staff?
+      PostLocker.new(@post, @editor).lock
+    end
+
     # WARNING: do not pull this into the transaction
     # it can fire events in sidekiq before the post is done saving
     # leading to corrupt state

spec/components/post_revisor_spec.rb

@@ -391,6 +391,66 @@ describe PostRevisor do
       end
     end
 
+    context "staff_edit_locks_post" do
+
+      context "disabled" do
+        before do
+          SiteSetting.staff_edit_locks_post = false
+        end
+
+        it "does not lock the post when revised" do
+          result = subject.revise!(
+            Fabricate(:moderator),
+            raw: "lets totally update the body"
+          )
+          expect(result).to eq(true)
+          post.reload
+          expect(post).not_to be_locked
+        end
+      end
+
+      context "enabled" do
+        let(:moderator) { Fabricate(:moderator) }
+
+        before do
+          SiteSetting.staff_edit_locks_post = true
+        end
+
+        it "locks the post when revised by staff" do
+          result = subject.revise!(
+            moderator,
+            raw: "lets totally update the body"
+          )
+          expect(result).to eq(true)
+          post.reload
+          expect(post).to be_locked
+        end
+
+        it "doesn't lock the post when revised by a regular user" do
+          result = subject.revise!(
+            Fabricate(:user),
+            raw: "lets totally update the body"
+          )
+          expect(result).to eq(true)
+          post.reload
+          expect(post).not_to be_locked
+        end
+
+        it "doesn't lock a staff member's post" do
+          staff_post = Fabricate(:post, user: moderator)
+          revisor = PostRevisor.new(staff_post)
+
+          result = revisor.revise!(
+            moderator,
+            raw: "lets totally update the body"
+          )
+          expect(result).to eq(true)
+          staff_post.reload
+          expect(staff_post).not_to be_locked
+        end
+      end
+    end
+
     context "tagging" do
       context "tagging disabled" do
         before do