Add default_i18n_subject AST matcher

lib/i18n/tasks/scanners/ast_matchers/default_i18n_subject_matcher.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require 'i18n/tasks/scanners/results/occurrence'
+
+module I18n::Tasks::Scanners::AstMatchers
+  class DefaultI18nSubjectMatcher < BaseMatcher
+    def convert_to_key_occurrences(send_node, method_name, location: send_node.loc)
+      children = Array(send_node&.children)
+      return unless children[1] == :default_i18n_subject
+
+      key = @scanner.absolute_key(
+        '.subject',
+        location.expression.source_buffer.name,
+        calling_method: method_name
+      )
+      [
+        key,
+        I18n::Tasks::Scanners::Results::Occurrence.from_range(
+          raw_key: key,
+          range: location.expression
+        )
+      ]
+    end
+  end
+end

spec/fixtures/used_keys/app/mailers/user_mailer.rb

@@ -0,0 +1,7 @@
+class UserMailer < ApplicationMailer
+  def welcome_notification
+    I18n.with_locale(:en) do
+      mail subject: default_i18n_subject
+    end
+  end
+end

spec/used_keys_ruby_spec.rb

@@ -2,6 +2,7 @@
 
 require 'spec_helper'
 require 'i18n/tasks/scanners/ast_matchers/rails_model_matcher'
+require 'i18n/tasks/scanners/ast_matchers/default_i18n_subject_matcher'
 
 RSpec.describe 'UsedKeysRuby' do
   let!(:task) { I18n::Tasks::BaseTask.new }
@@ -13,7 +14,8 @@
     true
   end
   let(:ast_matchers) do
-    %w[I18n::Tasks::Scanners::AstMatchers::RailsModelMatcher]
+    %w[I18n::Tasks::Scanners::AstMatchers::RailsModelMatcher
+       I18n::Tasks::Scanners::AstMatchers::DefaultI18nSubjectMatcher]
   end
 
   around do |ex|
@@ -134,10 +136,12 @@
   end
 
   describe 'relative_roots' do
-    let(:paths) { %w[app/components/event_component.rb app/controllers/events_controller.rb] }
+    let(:paths) do
+      %w[app/components/event_component.rb app/controllers/events_controller.rb app/mailers/user_mailer.rb]
+    end
     let(:extra_search_config) do
       {
-        relative_roots: %w[app/components app/controllers],
+        relative_roots: %w[app/components app/controllers app/mailers],
         relative_exclude_method_name_paths: %w[app/components]
       }
     end
@@ -146,7 +150,7 @@
       used_keys = task.used_tree
       expect(used_keys.size).to eq(1)
       leaves = used_keys.leaves.to_a
-      expect(leaves.size).to(eq(4))
+      expect(leaves.size).to(eq(5))
 
       expect_node_key_data(
         leaves[0],
@@ -222,6 +226,23 @@
           ]
         )
       )
+
+      expect_node_key_data(
+        leaves[4],
+        'user_mailer.welcome_notification.subject',
+        occurrences: make_occurrences(
+          [
+            {
+              path: 'app/mailers/user_mailer.rb',
+              pos: 113,
+              line_num: 4,
+              line_pos: 20,
+              line: '      mail subject: default_i18n_subject',
+              raw_key: 'user_mailer.welcome_notification.subject'
+            }
+          ]
+        )
+      )
     end
   end
 end

templates/config/i18n-tasks.yml

@@ -92,9 +92,12 @@ search:
   ## - RailsModelMatcher
   ##     Matches ActiveRecord translations like
   ##     User.human_attribute_name(:email) and User.model_name.human
+  ## - DefaultI18nSubjectMatcher
+  ##     Matches ActionMailer's default_i18n_subject method
   ##
   ## To implement your own, please see `I18n::Tasks::Scanners::AstMatchers::BaseMatcher`.
   # <%# I18n::Tasks.add_ast_matcher('I18n::Tasks::Scanners::AstMatchers::RailsModelMatcher') %>
+  # <%# I18n::Tasks.add_ast_matcher('I18n::Tasks::Scanners::AstMatchers::DefaultI18nSubjectMatcher') %>
 
   ## Multiple scanners can be used. Their results are merged.
   ## The options specified above are passed down to each scanner. Per-scanner options can be specified as well.