Remove customer service_desk_custom_address flag

This flag is not needed anymore

app/models/project.rb

@@ -2486,16 +2486,12 @@ class Project < ApplicationRecord
   end
 
   def service_desk_custom_address
-    return unless service_desk_custom_address_enabled?
+    return unless Gitlab::ServiceDeskEmail.enabled?
 
     key = service_desk_setting&.project_key
     return unless key.present?
 
-    ::Gitlab::ServiceDeskEmail.address_for_key("#{full_path_slug}-#{key}")
-  end
-
-  def service_desk_custom_address_enabled?
-    ::Gitlab::ServiceDeskEmail.enabled? && ::Feature.enabled?(:service_desk_custom_address, self, default_enabled: true)
+    Gitlab::ServiceDeskEmail.address_for_key("#{full_path_slug}-#{key}")
   end
 
   def root_namespace

app/services/service_desk_settings/update_service.rb

@@ -5,10 +5,6 @@ module ServiceDeskSettings
     def execute
       settings = ServiceDeskSetting.safe_find_or_create_by!(project_id: project.id)
 
-      unless ::Feature.enabled?(:service_desk_custom_address, project, default_enabled: true)
-        params.delete(:project_key)
-      end
-
       params[:project_key] = nil if params[:project_key].blank?
 
       if settings.update(params)

app/views/projects/_service_desk_settings.html.haml

@@ -12,7 +12,7 @@
         enabled: "#{@project.service_desk_enabled}",
         incoming_email: (@project.service_desk_incoming_address if @project.service_desk_enabled),
         custom_email: (@project.service_desk_custom_address if @project.service_desk_enabled),
-        custom_email_enabled: "#{@project.service_desk_custom_address_enabled?}",
+        custom_email_enabled: "#{Gitlab::ServiceDeskEmail.enabled?}",
         selected_template: "#{@project.service_desk_setting&.issue_template_key}",
         outgoing_name: "#{@project.service_desk_setting&.outgoing_name}",
         project_key: "#{@project.service_desk_setting&.project_key}",

config/feature_flags/development/service_desk_custom_address.yml

----
-name: service_desk_custom_address
-introduced_by_url:
-rollout_issue_url: https://gitlab.com/gitlab-org/gitlab/-/issues/284656
-milestone:
-type: development
-group: group::certify
-default_enabled: true

doc/user/project/service_desk.md

@@ -140,15 +140,12 @@ To edit the custom email display name:
 ### Using custom email address
 
 > - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/2201) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.0.
-> - It was [deployed behind a feature flag](../feature_flags.md), disabled by default.
-> - [Became enabled by default](https://gitlab.com/gitlab-org/gitlab/-/issues/284656) on GitLab 13.7.
-> - It's enabled on GitLab.com.
-> - It's recommended for production use.
-> - For GitLab self-managed instances, GitLab administrators can opt to [disable it](#disable-custom-email-address). **(CORE ONLY)**
+> - [Feature flag removed](https://gitlab.com/gitlab-org/gitlab/-/issues/284656) in GitLab 13.8.
 
-If the `service_desk_email` feature flag is enabled, then you can
-create Service Desk issues by sending emails to the Service Desk email address.
-The default address has the following format: `project_contact+%{key}@example.com`.
+If the `service_desk_email` is configured, then you can create Service Desk
+issues by sending emails to the Service Desk email address. The default
+address has the following format:
+`project_contact+%{key}@example.com`.
 
 The `%{key}` part is used to find the project where the issue should be created. The
 `%{key}` part combines the path to the project and configurable project name suffix:
@@ -163,7 +160,7 @@ always use separate mailboxes. This is important, because emails picked from
 `service_desk_email` mailbox are processed by a different worker and it would
 not recognize `incoming_email` emails.
 
-You can add the following snippets to your configuration:
+To configure a custom email address for Service Desk, add the following snippets to your configuration file:
 
 - Example for installations from source:
 
@@ -216,23 +213,6 @@ As a result, a new Service Desk issue is created from this email in the `mygroup
 The configuration options are the same as for configuring
 [incoming email](../../administration/incoming_email.md#set-it-up).
 
-#### Disable custom email address **(CORE ONLY)**
-
-Service Desk custom email is under development but ready for production use.
-It is deployed behind a feature flag that is **enabled by default**.
-
-To disable it:
-
-```ruby
-Feature.disable(:service_desk_custom_address)
-```
-
-To enable it:
-
-```ruby
-Feature.enable(:service_desk_custom_address)
-```
-
 ## Using Service Desk
 
 There are a few ways Service Desk can be used.

lib/gitlab/email/handler/service_desk_handler.rb

@@ -68,7 +68,7 @@ module Gitlab
         end
 
         def valid_project_key?(project, slug)
-          project.present? && slug == project.full_path_slug && Feature.enabled?(:service_desk_custom_address, project, default_enabled: true)
+          project.present? && slug == project.full_path_slug
         end
 
         def create_issue!

spec/lib/gitlab/email/handler/service_desk_handler_spec.rb

@@ -191,16 +191,6 @@ RSpec.describe Gitlab::Email::Handler::ServiceDeskHandler do
             expect { receiver.execute }.to raise_error(Gitlab::Email::ProjectNotFound)
           end
         end
-
-        context 'when service_desk_custom_address feature is disabled' do
-          before do
-            stub_feature_flags(service_desk_custom_address: false)
-          end
-
-          it 'bounces the email' do
-            expect { receiver.execute }.to raise_error(Gitlab::Email::ProjectNotFound)
-          end
-        end
       end
     end
 

spec/models/project_spec.rb

@@ -1499,63 +1499,13 @@ RSpec.describe Project, factory_default: :keep do
         allow(::Gitlab::ServiceDeskEmail).to receive(:config).and_return(config)
       end
 
-      context 'when service_desk_custom_address flag is enabled' do
-        before do
-          stub_feature_flags(service_desk_custom_address: true)
-        end
-
-        it 'returns custom address when project_key is set' do
-          create(:service_desk_setting, project: project, project_key: 'key1')
-
-          expect(subject).to eq("foo+#{project.full_path_slug}-key1@bar.com")
-        end
-
-        it_behaves_like 'with incoming email address'
-      end
-
-      context 'when service_desk_custom_address flag is disabled' do
-        before do
-          stub_feature_flags(service_desk_custom_address: false)
-        end
-
-        it_behaves_like 'with incoming email address'
-      end
-    end
-  end
-
-  describe '.service_desk_custom_address_enabled?' do
-    let_it_be(:project) { create(:project, service_desk_enabled: true) }
-
-    subject(:address_enabled) { project.service_desk_custom_address_enabled? }
-
-    context 'when service_desk_email is enabled' do
-      before do
-        allow(::Gitlab::ServiceDeskEmail).to receive(:enabled?).and_return(true)
-      end
-
-      it 'returns true' do
-        expect(address_enabled).to be_truthy
-      end
-
-      context 'when service_desk_custom_address flag is disabled' do
-        before do
-          stub_feature_flags(service_desk_custom_address: false)
-        end
-
-        it 'returns false' do
-          expect(address_enabled).to be_falsey
-        end
-      end
-    end
+      it 'returns custom address when project_key is set' do
+        create(:service_desk_setting, project: project, project_key: 'key1')
 
-    context 'when service_desk_email is disabled' do
-      before do
-        allow(::Gitlab::ServiceDeskEmail).to receive(:enabled?).and_return(false)
+        expect(subject).to eq("foo+#{project.full_path_slug}-key1@bar.com")
       end
 
-      it 'returns false when service_desk_email is disabled' do
-        expect(address_enabled).to be_falsey
-      end
+      it_behaves_like 'with incoming email address'
     end
   end
 

spec/services/service_desk_settings/update_service_spec.rb

@@ -16,19 +16,6 @@ RSpec.describe ServiceDeskSettings::UpdateService do
         expect(settings.reload.outgoing_name).to eq 'some name'
         expect(settings.reload.project_key).to eq 'foo'
       end
-
-      context 'when service_desk_custom_address is disabled' do
-        before do
-          stub_feature_flags(service_desk_custom_address: false)
-        end
-
-        it 'ignores project_key parameter' do
-          result = described_class.new(settings.project, user, params).execute
-
-          expect(result[:status]).to eq :success
-          expect(settings.reload.project_key).to be_nil
-        end
-      end
     end
 
     context 'when project_key is an empty string' do