Fix translations for vulnerabilities dismissal reason

Translate descriptions for declarative_enum dynamically using N_(...)
combined with `_(var)`.

Prior this change the translated strings were loaded in class scope so
switching the locale had no effect on them anymore. The descriptions
were always displayed in English.

app/models/application_record.rb

@@ -91,8 +91,7 @@ class ApplicationRecord < ActiveRecord::Base
   end
 
   def self.declarative_enum(enum_mod)
-    values = enum_mod.definition.transform_values { |v| v[:value] }
-    enum(enum_mod.key => values)
+    enum(enum_mod.key => enum_mod.values)
   end
 
   def self.cached_column_list

ee/app/enums/vulnerabilities/dismissal_reason_enum.rb

@@ -9,11 +9,11 @@ module Vulnerabilities
     description 'The dismissal reason of the Vulnerability'
 
     define do
-      acceptable_risk value: 0, description: _('The vulnerability is known, and has not been remediated or mitigated, but is considered to be an acceptable business risk.')
-      false_positive value: 1, description: _('An error in reporting in which a test result incorrectly indicates the presence of a vulnerability in a system when the vulnerability is not present.')
-      mitigating_control value: 2, description: _('A management, operational, or technical control (that is, safeguard or countermeasure) employed by an organization that provides equivalent or comparable protection for an information system.')
-      used_in_tests value: 3, description: _('The finding is not a vulnerability because it is part of a test or is test data.')
-      not_applicable value: 4, description: _('The vulnerability is known, and has not been remediated or mitigated, but is considered to be in a part of the application that will not be updated.')
+      acceptable_risk value: 0, description: N_('The vulnerability is known, and has not been remediated or mitigated, but is considered to be an acceptable business risk.')
+      false_positive value: 1, description: N_('An error in reporting in which a test result incorrectly indicates the presence of a vulnerability in a system when the vulnerability is not present.')
+      mitigating_control value: 2, description: N_('A management, operational, or technical control (that is, safeguard or countermeasure) employed by an organization that provides equivalent or comparable protection for an information system.')
+      used_in_tests value: 3, description: N_('The finding is not a vulnerability because it is part of a test or is test data.')
+      not_applicable value: 4, description: N_('The vulnerability is known, and has not been remediated or mitigated, but is considered to be in a part of the application that will not be updated.')
     end
   end
 end

ee/app/helpers/vulnerabilities_helper.rb

@@ -32,7 +32,7 @@ module VulnerabilitiesHelper
   end
 
   def dismissal_descriptions
-    Vulnerabilities::DismissalReasonEnum.definition.transform_values { |v| v[:description] }
+    Vulnerabilities::DismissalReasonEnum.translated_descriptions
   end
 
   def new_issue_url_for(vulnerability)

ee/spec/helpers/vulnerabilities_helper_spec.rb

@@ -175,8 +175,21 @@ RSpec.describe VulnerabilitiesHelper do
         }
       end
 
-      it 'incldues dismissal descriptions' do
-        expect(subject[:dismissal_descriptions]).to eq(expected_descriptions)
+      let(:translated_descriptions) do
+        # Use dynamic translations via N_(...)
+        expected_descriptions.values.map { |description| _(description) }
+      end
+
+      it 'includes translated dismissal descriptions' do
+        Gitlab::I18n.with_locale(:en) do
+          # Force loading of the class and configured translations
+          Vulnerabilities::DismissalReasonEnum.translated_descriptions
+        end
+
+        Gitlab::I18n.with_locale(:zh_CN) do
+          expect(subject[:dismissal_descriptions].keys).to eq(expected_descriptions.keys)
+          expect(subject[:dismissal_descriptions].values).to eq(translated_descriptions)
+        end
       end
     end
   end

lib/declarative_enum.rb

@@ -15,9 +15,9 @@
 #     TEXT
 #
 #     define do
-#       acceptable_risk value: 0, description: 'The vulnerability is known but is considered to be an acceptable business risk.'
-#       false_positive value: 1, description: 'An error in reporting the presence of a vulnerability in a system when the vulnerability is not present.'
-#       used_in_tests value: 2, description: 'The finding is not a vulnerability because it is part of a test or is test data.'
+#       acceptable_risk value: 0, description: N_('The vulnerability is known but is considered to be an acceptable business risk.')
+#       false_positive value: 1, description: N_('An error in reporting the presence of a vulnerability in a system when the vulnerability is not present.')
+#       used_in_tests value: 2, description: N_('The finding is not a vulnerability because it is part of a test or is test data.')
 #     end
 #
 # Then we can use this module to register enums for our Active Record models like so,
@@ -63,6 +63,19 @@ module DeclarativeEnum
     @description
   end
 
+  def values
+    definition.transform_values { |definition| definition[:value] }
+  end
+
+  # Return list of dynamically translated descriptions.
+  #
+  # It is required to define descriptions with `N_(...)`.
+  #
+  # See https://github.com/grosser/fast_gettext#n_-and-nn_-make-dynamic-translations-available-to-the-parser
+  def translated_descriptions
+    definition.transform_values { |definition| _(definition[:description]) }
+  end
+
   def define(&block)
     raise LocalJumpError, 'No block given' unless block