FIX: use a custom prefix for custom flags (#28839)

Currently, when the custom flag has the same name as the system flag (which is disabled) then it is not displayed. To fix the problem, `custom_` prefix as `name_key` is used to distinguish between the system and the custom flag.

I considered writing a migration to fix existing custom flags name key. However, at the end of migration I would need to run rails code to reset cache `Flag.reset_flag_settings!`. I decided to skip that step as it is a very edge case. If someone has the same flag name as the system flag, then all they have to do is edit the flag and click save.

In addition, I made 2 small fixes:
- edit flag title was missing translation;
- flag form UI was not showing that description is the required field.

app/assets/javascripts/admin/addon/components/admin-flags-form.gjs

@@ -135,7 +135,7 @@ export default class AdminFlagsForm extends Component {
             <form.Field
               @name="description"
               @title={{i18n "admin.config_areas.flags.form.description"}}
-              @validation="length:0,1000"
+              @validation="required|length:3,1000"
               as |field|
             >
               <field.Textarea @height={{60}} />

app/models/flag.rb

@@ -43,7 +43,7 @@ class Flag < ActiveRecord::Base
   end
 
   def system?
-    self.id < MAX_SYSTEM_FLAG_ID
+    self.id.present? && self.id < MAX_SYSTEM_FLAG_ID
   end
 
   def applies_to?(type)
@@ -61,7 +61,8 @@ class Flag < ActiveRecord::Base
   end
 
   def set_name_key
-    self.name_key = self.name.squeeze(" ").gsub(" ", "_").gsub(/[^\w]/, "").downcase
+    prefix = self.system? ? "" : "custom_"
+    self.name_key = "#{prefix}#{self.name.squeeze(" ").gsub(" ", "_").gsub(/[^\w]/, "").downcase}"
   end
 end
 

config/locales/client.en.yml

@@ -5617,6 +5617,7 @@ en:
           saved: "saved!"
         flags:
           header: "Moderation Flags"
+          edit_header: "Edit Flag"
           subheader: "The flagging system in Discourse helps you and your moderator team manage content and user behavior, keeping your community respectful and healthy. The defaults are suitable for most communities and you don’t have to change them. However, if your site has particular requirements you can disable flags you don’t need and add your own custom flags."
           description: "Description"
           enabled: "Enabled?"

spec/lib/post_action_type_view_spec.rb

@@ -29,8 +29,8 @@ RSpec.describe PostActionTypeView do
     )
     expect(post_action_type_view.score_types).to eq({ needs_approval: 9 })
 
-    flag = Fabricate(:flag, name: "custom", enabled: false)
-    expect(PostActionTypeView.new.disabled_flag_types).to eq({ custom: flag.id })
+    flag = Fabricate(:flag, name: "flag", enabled: false)
+    expect(PostActionTypeView.new.disabled_flag_types).to eq({ custom_flag: flag.id })
     flag.destroy!
   end
 

spec/models/flag_spec.rb

@@ -17,14 +17,14 @@ RSpec.describe Flag, type: :model do
   end
 
   it "has correct name key" do
-    flag = Fabricate(:flag, name: "CuStOm Flag!!!")
+    flag = Fabricate(:flag, name: "FlAg!!!")
     expect(flag.name_key).to eq("custom_flag")
 
     flag.update!(name: "It's Illegal")
-    expect(flag.name_key).to eq("its_illegal")
+    expect(flag.name_key).to eq("custom_its_illegal")
 
     flag.update!(name: "THIS IS    SPaM!+)(*&^%$#@@@!)")
-    expect(flag.name_key).to eq("this_is_spam")
+    expect(flag.name_key).to eq("custom_this_is_spam")
 
     flag.destroy!
   end
@@ -37,17 +37,9 @@ RSpec.describe Flag, type: :model do
       %i[notify_user off_topic inappropriate spam illegal notify_moderators needs_approval],
     )
 
-    flag = Fabricate(:flag, name: "custom")
+    flag = Fabricate(:flag, name: "flag")
     expect(PostActionType.flag_types.keys).to eq(
-      %i[notify_user off_topic inappropriate spam illegal notify_moderators custom],
-    )
-    expect(ReviewableScore.types.keys).to eq(
-      %i[notify_user off_topic inappropriate spam illegal notify_moderators custom needs_approval],
-    )
-
-    flag.update!(name: "edited_custom")
-    expect(PostActionType.flag_types.keys).to eq(
-      %i[notify_user off_topic inappropriate spam illegal notify_moderators edited_custom],
+      %i[notify_user off_topic inappropriate spam illegal notify_moderators custom_flag],
     )
     expect(ReviewableScore.types.keys).to eq(
       %i[
@@ -57,7 +49,24 @@ RSpec.describe Flag, type: :model do
         spam
         illegal
         notify_moderators
-        edited_custom
+        custom_flag
+        needs_approval
+      ],
+    )
+
+    flag.update!(name: "edited_flag")
+    expect(PostActionType.flag_types.keys).to eq(
+      %i[notify_user off_topic inappropriate spam illegal notify_moderators custom_edited_flag],
+    )
+    expect(ReviewableScore.types.keys).to eq(
+      %i[
+        notify_user
+        off_topic
+        inappropriate
+        spam
+        illegal
+        notify_moderators
+        custom_edited_flag
         needs_approval
       ],
     )

spec/models/post_action_spec.rb

@@ -791,7 +791,7 @@ RSpec.describe PostAction do
         PostActionCreator.new(
           Discourse.system_user,
           post,
-          PostActionType.types[:flag_without_message],
+          PostActionType.types[:custom_flag_without_message],
           message: "WAT",
         ).perform
 
@@ -824,7 +824,7 @@ RSpec.describe PostAction do
         PostActionCreator.new(
           Discourse.system_user,
           post,
-          PostActionType.types[:flag_with_message],
+          PostActionType.types[:custom_flag_with_message],
           message: "WAT",
         ).perform
 

spec/system/admin_flags_spec.rb

@@ -108,7 +108,7 @@ describe "Admin Flags Page", type: :system do
     )
 
     # update
-    admin_flags_page.visit.click_edit_flag("vulgar")
+    admin_flags_page.visit.click_edit_flag("custom_vulgar")
     admin_flag_form_page.fill_in_name("Tasteless").click_save
 
     expect(admin_flags_page).to have_flags(
@@ -132,7 +132,7 @@ describe "Admin Flags Page", type: :system do
     )
 
     # delete
-    admin_flags_page.visit.click_delete_flag("tasteless").confirm_delete
+    admin_flags_page.visit.click_delete_flag("custom_tasteless").confirm_delete
 
     expect(admin_flags_page).to have_no_flag("tasteless")
 
@@ -146,6 +146,28 @@ describe "Admin Flags Page", type: :system do
       "It's Illegal",
       "Something Else",
     )
+
+    # custom flag with same name as system flag
+    admin_flags_page.visit.toggle("inappropriate")
+    admin_flags_page.click_add_flag
+    admin_flag_form_page
+      .fill_in_name("Inappropriate")
+      .fill_in_description("New flag description")
+      .select_applies_to("Topic")
+      .select_applies_to("Post")
+      .click_save
+
+    topic_page.visit_topic(post.topic).open_flag_topic_modal
+
+    expect(flag_modal).to have_choices(
+      "It's Spam",
+      "It's Illegal",
+      "Something Else",
+      "Inappropriate",
+    )
+
+    Flag.system.where(name: "illegal").update!(enabled: true)
+    admin_flags_page.visit.click_delete_flag("custom_inappropriate").confirm_delete
   end
 
   it "has settings tab" do