Backport CE changes

Backports CE changes from
https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/14011/

db/migrate/20190527011309_add_required_template_name_to_application_settings.rb

@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class AddRequiredTemplateNameToApplicationSettings < ActiveRecord::Migration[5.1]
+  include Gitlab::Database::MigrationHelpers
+
+  # Set this constant to true if this migration requires downtime.
+  DOWNTIME = false
+
+  def change
+    add_column :application_settings, :required_instance_ci_template, :string, null: true
+  end
+end

db/schema.rb

@@ -193,6 +193,7 @@ ActiveRecord::Schema.define(version: 20190530154715) do
     t.integer "elasticsearch_replicas", default: 1, null: false
     t.text "encrypted_lets_encrypt_private_key"
     t.text "encrypted_lets_encrypt_private_key_iv"
+    t.string "required_instance_ci_template"
     t.boolean "dns_rebinding_protection_enabled", default: true, null: false
     t.index ["usage_stats_set_by_user_id"], name: "index_application_settings_on_usage_stats_set_by_user_id", using: :btree
   end

lib/gitlab/ci/config.rb

@@ -8,6 +8,12 @@ module Gitlab
     class Config
       ConfigError = Class.new(StandardError)
 
+      RESCUE_ERRORS = [
+        Gitlab::Config::Loader::FormatError,
+        Extendable::ExtensionError,
+        External::Processor::IncludeError
+      ].freeze
+
       def initialize(config, project: nil, sha: nil, user: nil)
         @config = Config::Extendable
           .new(build_config(config, project: project, sha: sha, user: user))
@@ -15,9 +21,7 @@ module Gitlab
 
         @global = Entry::Global.new(@config)
         @global.compose!
-      rescue Gitlab::Config::Loader::FormatError,
-             Extendable::ExtensionError,
-             External::Processor::IncludeError => e
+      rescue *rescue_errors => e
         raise Config::ConfigError, e.message
       end
 
@@ -83,6 +87,11 @@ module Gitlab
           user: user,
           expandset: Set.new).perform
       end
+
+      # Overriden in EE
+      def rescue_errors
+        RESCUE_ERRORS
+      end
     end
   end
 end