Switch from I18n::MissingTranslationData (which is an Exception) to I…

…18n::MissingTranslation (which is a plain Object) for the default case. Create an I18n::MissingTranslationData exception only if it needs to be raised to the user.

lib/i18n.rb

@@ -156,7 +156,7 @@ def translate(*args)
           backend.translate(locale, key, options)
         end
       end
-      result.is_a?(MissingTranslationData) ? handle_exception(handling, result, locale, key, options) : result
+      result.is_a?(MissingTranslation) ? handle_exception(handling, result, locale, key, options) : result
     end
     alias :t :translate
 
@@ -266,7 +266,7 @@ def normalize_keys(locale, key, scope, separator = nil)
 
     # Any exceptions thrown in translate will be sent to the @@exception_handler
     # which can be a Symbol, a Proc or any other Object unless they're forced to
-    # be raised or thrown (MissingTranslationData).
+    # be raised or thrown (MissingTranslation).
     #
     # If exception_handler is a Symbol then it will simply be sent to I18n as
     # a method call. A Proc will simply be called. In any other case the
@@ -285,7 +285,7 @@ def normalize_keys(locale, key, scope, separator = nil)
     def handle_exception(handling, exception, locale, key, options)
       case handling
       when :raise
-        raise exception
+        raise(exception.respond_to?(:to_exception) ? exception.to_exception : exception)
       when :throw
         throw :exception, exception
       else
@@ -325,8 +325,7 @@ def normalize_translation_keys(locale, key, scope, separator = nil)
     def default_exception_handler(exception, locale, key, options)
       puts "I18n.default_exception_handler is deprecated. Please use the class I18n::ExceptionHandler instead " +
            "(an instance of which is set to I18n.exception_handler by default)."
-      return exception.message if MissingTranslationData === exception
-      raise exception
+      exception.is_a?(MissingTranslation) ? exception.message : raise(exception)
     end
   end
 end

lib/i18n/backend/base.rb

@@ -34,7 +34,7 @@ def translate(locale, key, options = {})
             default(locale, key, default, options) : resolve(locale, key, entry, options)
         end
 
-        throw(:exception, I18n::MissingTranslationData.new(locale, key, options)) if entry.nil?
+        throw(:exception, I18n::MissingTranslation.new(locale, key, options)) if entry.nil?
         entry = entry.dup if entry.is_a?(String)
 
         entry = pluralize(locale, entry, count) if count
@@ -119,7 +119,7 @@ def resolve(locale, object, subject, options = {})
               subject
             end
           end
-          result unless result.is_a?(MissingTranslationData)
+          result unless result.is_a?(MissingTranslation)
         end
 
         # Picks a translation from an array according to English pluralization

lib/i18n/backend/cache.rb

@@ -70,7 +70,7 @@ def translate(locale, key, options = {})
 
         def fetch(cache_key, &block)
           result = _fetch(cache_key, &block)
-          throw(:exception, result) if result.is_a?(MissingTranslationData)
+          throw(:exception, result) if result.is_a?(MissingTranslation)
           result = result.dup if result.frozen? rescue result
           result
         end

lib/i18n/backend/chain.rb

@@ -54,7 +54,7 @@ def translate(locale, key, default_options = {})
           end
 
           return namespace if namespace
-          throw(:exception, I18n::MissingTranslationData.new(locale, key, options))
+          throw(:exception, I18n::MissingTranslation.new(locale, key, options))
         end
 
         def localize(locale, object, format = :default, options = {})
@@ -63,7 +63,7 @@ def localize(locale, object, format = :default, options = {})
               result = backend.localize(locale, object, format, options) and return result
             end
           end
-          throw(:exception, I18n::MissingTranslationData.new(locale, format, options))
+          throw(:exception, I18n::MissingTranslation.new(locale, format, options))
         end
 
         protected

lib/i18n/backend/fallbacks.rb

@@ -29,8 +29,7 @@ module Fallbacks
       # locale :"de-DE" it might try the locales :"de-DE", :de and :en
       # (depends on the fallbacks implementation) until it finds a result with
       # the given options. If it does not find any result for any of the
-      # locales it will then raise a MissingTranslationData exception as
-      # usual.
+      # locales it will then throw MissingTranslation as usual.
       #
       # The default option takes precedence over fallback locales
       # only when it's a Symbol. When the default contains a String or a Proc
@@ -49,7 +48,7 @@ def translate(locale, key, options = {})
         options.delete(:fallback)
 
         return super(locale, nil, options.merge(:default => default)) if default
-        throw(:exception, I18n::MissingTranslationData.new(locale, key, options))
+        throw(:exception, I18n::MissingTranslation.new(locale, key, options))
       end
 
       def extract_string_or_lambda_default!(options)

lib/i18n/exceptions.rb

@@ -6,7 +6,7 @@ module I18n
   class ExceptionHandler
     include Module.new {
       def call(exception, locale, key, options)
-        if exception.is_a?(MissingTranslationData)
+        if exception.is_a?(MissingTranslation)
           options[:rescue_format] == :html ? exception.html_message : exception.message
         else
           raise exception
@@ -33,25 +33,41 @@ def initialize(filename)
     end
   end
 
-  class MissingTranslationData < ArgumentError
-    attr_reader :locale, :key, :options
+  class MissingTranslation
+    module Base
+      attr_reader :locale, :key, :options
 
-    def initialize(locale, key, opts = nil)
-      @key, @locale, @options = key, locale, opts.dup || {}
-      options.each { |k, v| options[k] = v.inspect if v.is_a?(Proc) }
-      super "translation missing: #{keys.join('.')}"
-    end
+      def initialize(locale, key, options = nil)
+        @key, @locale, @options = key, locale, options.dup || {}
+        options.each { |k, v| self.options[k] = v.inspect if v.is_a?(Proc) }
+      end
 
-    def html_message
-      key = keys.last.to_s.gsub('_', ' ').gsub(/\b('?[a-z])/) { $1.capitalize }
-      %(<span class="translation_missing" title="translation missing: #{keys.join('.')}">#{key}</span>)
-    end
+      def html_message
+        key = keys.last.to_s.gsub('_', ' ').gsub(/\b('?[a-z])/) { $1.capitalize }
+        %(<span class="translation_missing" title="translation missing: #{keys.join('.')}">#{key}</span>)
+      end
+
+      def keys
+        @keys ||= I18n.normalize_keys(locale, key, options[:scope]).tap do |keys|
+          keys << 'no key' if keys.size < 2
+        end
+      end
+
+      def message
+        "translation missing: #{keys.join('.')}"
+      end
+      alias :to_s :message
 
-    def keys
-      @keys ||= I18n.normalize_keys(locale, key, options[:scope]).tap do |keys|
-        keys << 'no key' if keys.size < 2
+      def to_exception
+        MissingTranslationData.new(locale, key, options)
       end
     end
+
+    include Base
+  end
+
+  class MissingTranslationData < ArgumentError
+    include MissingTranslation::Base
   end
 
   class InvalidPluralizationData < ArgumentError

lib/i18n/rails/translation_helper.rb

@@ -9,7 +9,7 @@ class ExceptionHandler
     # are forced to html_safe
     include Module.new {
       def call(exception, locale, key, options)
-        exception.is_a?(MissingTranslationData) ? super.html_safe : super
+        exception.is_a?(MissingTranslation) ? super.html_safe : super
       end
     }
   end
@@ -22,7 +22,7 @@ module TranslationHelper
       # Delegates to I18n#translate but also performs three additional functions.
       #
       # First, it'll pass the :rescue_format => :html option to I18n so that any caught
-      # MissingTranslationData exceptions will be turned into inline spans that
+      # MissingTranslation exceptions will be turned into inline spans that
       #
       #   * have a "translation-missing" class set,
       #   * contain the missing key as a title attribute and

test/backend/exceptions_test.rb

@@ -5,6 +5,13 @@ def setup
     I18n.backend = I18n::Backend::Simple.new
   end
 
+  test "throw message: MissingTranslation message from #translate includes the given scope and full key" do
+    exception = catch(:exception) do
+      I18n.t(:'baz.missing', :scope => :'foo.bar', :throw => true)
+    end
+    assert_equal "translation missing: en.foo.bar.baz.missing", exception.message
+  end
+
   test "exceptions: MissingTranslationData message from #translate includes the given scope and full key" do
     begin
       I18n.t(:'baz.missing', :scope => :'foo.bar', :raise => true)

test/i18n_test.rb

@@ -197,8 +197,8 @@ def setup
   test "can use a lambda as an exception handler" do
     begin
       previous_exception_handler = I18n.exception_handler
-      I18n.exception_handler = Proc.new { |exception, locale, key, options| exception }
-      assert_equal I18n::MissingTranslationData, I18n.translate(:test_proc_handler).class
+      I18n.exception_handler = Proc.new { |exception, locale, key, options| key }
+      assert_equal :test_proc_handler, I18n.translate(:test_proc_handler)
     ensure
       I18n.exception_handler = previous_exception_handler
     end
@@ -208,9 +208,9 @@ def setup
     begin
       previous_exception_handler = I18n.exception_handler
       I18n.exception_handler = Class.new do
-        def call(exception, locale, key, options); exception; end
+        def call(exception, locale, key, options); key; end
       end.new
-      assert_equal I18n::MissingTranslationData, I18n.translate(:test_proc_handler).class
+      assert_equal :test_proc_handler, I18n.translate(:test_proc_handler)
     ensure
       I18n.exception_handler = previous_exception_handler
     end