i18n-tasks missing resulting in false positive when I18n.t is called from a helper

[lucascaton]

Hi there, I think have found a bug :-)

With a simple Rails app:

# app/helpers/pages_helper.rb
module PagesHelper
  def locale_test
    t '.something'
  end
end

<%# app/views/pages/index.html.erb %>
<h1><%= locale_test %></h1>

# config/locales/en.yml
en:
  pages:
    index:
      something: 'Something!!!'

It works:

But:

$ i18n-tasks missing

Missing translations (1) | i18n-tasks v0.9.4
+--------+------------------------------------+----------------------------------+
| Locale | Key                                | Value in other locales or source |
+--------+------------------------------------+----------------------------------+
|  all   | pages_helper.locale_test.something | app/helpers/pages_helper.rb:3    |
+--------+------------------------------------+----------------------------------+

[lucascaton]

I tried to add # i18n-tasks-use, but it didn't work as well:

# app/helpers/pages_helper.rb
module PagesHelper
  def locale_test
    # i18n-tasks-use t('pages.index.something')
    t '.something'
  end
end

(running $ i18n-tasks missing I get the same false positive)

[glebm]

Unfortunately, this is not a bug but a limitation of i18n-tasks. The static analysis always resolves relative keys based on the filename (+ the enclosing method name in case of .rb files).

There are ways to work around this. First, make i18n-tasks ignore this key:

ignore_missing:
# Ignore this relative key defined in a helper, as it is resolved differently
# depending on where the helper is called from. We handle these separately in ...
- pages_helper.locale_test.something

Then, there are two options:

A) Add an i18n-tasks-use hint at every call sites, e.g.:

<h1>
  <%# i18n-tasks-use t('pages.index.something') %>
  <%= locale_test %>
</h1>

This is a good option if there are few call sites.

B) Add a custom scanner for calls to locale_test:

# config/i18n-tasks/something_scanner.rb
require 'i18n/tasks/scanners/file_scanner'
class SomethingScanner < I18n::Tasks::Scanners::FileScanner
  include I18n::Tasks::Scanners::RelativeKeys
  include I18n::Tasks::Scanners::OccurrenceFromPosition

  # @return [Array<[absolute key, Results::Occurrence]>]
  def scan_file(path)
    text = read_file(path)
    text.scan(/^\s*<%=\s*locale_test\b/).map do |_match|
      occurrence = occurrence_from_position(
          path, text, Regexp.last_match.offset(0).first)
      [absolute_key('.something', path), occurrence]
    end
  end
end
I18n::Tasks.add_scanner 'SomethingScanner', only: %w(*.html.erb)

# config/i18n-tasks.yml.erb
<% require './config/i18n-tasks/something_scanner.rb' %>

This is a better option if there are many call sites.

[lucascaton]

Hi @glebm, thanks for replying so quickly.

Wouldn't it be worth adding somehow this Scanner class to the gem codebase?

[glebm]

Perhaps it would make sense to add a scanner that maps patterns to keys, so it can be configured with something like:

<% I18n::Tasks.add_scanner, 'I18n::Tasks::Scanners::PatternMapper', only: %w(*.html.erb),
  patterns: [[/^\s*<%=\s*locale_test\b/, '.something']] %>

[glebm]

Released in v0.9.5. Simply add the key to ignore_missing and add this to the config:

<% I18n::Tasks.add_scanner 'I18n::Tasks::Scanners::PatternMapper',
                            only: %w(*.html.erb),
                            patterns: [['<%=\s*locale_test\b', '.something']] %>

[lucascaton]

Thanks @glebm!