7 files changed, 46 insertions, 12 deletions
diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index ea84b54b3f..4da6421ea4 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,3 +1,13 @@
+*   Add support for supplying `locale` to `transliterate` and `parameterize`.
+
+        I18n.backend.store_translations(:de, i18n: { transliterate: { rule: { "ü" => "ue" } } })
+
+        ActiveSupport::Inflector.transliterate("ü", locale: :de) => "ue"
+        "Fünf autos".parameterize(locale: :de) => "fuenf-autos"
+        ActiveSupport::Inflector.parameterize("Fünf autos", locale: :de) => "fuenf-autos"
+
+    *Kaan Ozkan*, *Sharang Dashputre*
+
 *   Allow Array#excluding and Enumerable#excluding to deal with a passed array gracefully.
 
         [ 1, 2, 3, 4, 5 ].excluding([4, 5]) => [ 1, 2, 3 ]
@@ -10,12 +20,13 @@
     *DHH*
 
 *   Added Array#including and Enumerable#including to conveniently enlarge a collection with more members using a method rather than an operator:
-    
+
         [ 1, 2, 3 ].including(4, 5) => [ 1, 2, 3, 4, 5 ]
         post.authors.including(Current.person) => All the authors plus the current person!
 
     *DHH*
 
+
 ## Rails 6.0.0.beta2 (February 25, 2019) ##
 
 *   New autoloading based on [Zeitwerk](https://github.com/fxn/zeitwerk).
@@ -44,6 +55,7 @@
 
     *Guillermo Iguaran*
 
+
 ## Rails 6.0.0.beta1 (January 18, 2019) ##
 
 *   Remove deprecated `Module#reachable?` method.
diff --git a/activesupport/activesupport.gemspec b/activesupport/activesupport.gemspec
index 2781d4e6f7..8409a0c420 100644
--- a/activesupport/activesupport.gemspec
+++ b/activesupport/activesupport.gemspec
@@ -34,5 +34,5 @@ Gem::Specification.new do |s|
   s.add_dependency "tzinfo",          "~> 1.1"
   s.add_dependency "minitest",        "~> 5.1"
   s.add_dependency "concurrent-ruby", "~> 1.0", ">= 1.0.2"
-  s.add_dependency "zeitwerk",        "~> 1.3", ">= 1.3.2"
+  s.add_dependency "zeitwerk",        "~> 1.3", ">= 1.3.3"
 end
diff --git a/activesupport/lib/active_support/core_ext/string/inflections.rb b/activesupport/lib/active_support/core_ext/string/inflections.rb
index 8af301734a..e63b38b227 100644
--- a/activesupport/lib/active_support/core_ext/string/inflections.rb
+++ b/activesupport/lib/active_support/core_ext/string/inflections.rb
@@ -162,6 +162,11 @@ class String
 
   # Replaces special characters in a string so that it may be used as part of a 'pretty' URL.
   #
+  # If the optional parameter +locale+ is specified,
+  # the word will be parameterized as a word of that language.
+  # By default, this parameter is set to <tt>nil</tt> and it will use
+  # configured I18n.locale
+  #
   #   class Person
   #     def to_param
   #       "#{id}-#{name.parameterize}"
@@ -187,8 +192,8 @@ class String
   #
   #   <%= link_to(@person.name, person_path) %>
   #   # => <a href="/person/1-Donald-E-Knuth">Donald E. Knuth</a>
-  def parameterize(separator: "-", preserve_case: false)
-    ActiveSupport::Inflector.parameterize(self, separator: separator, preserve_case: preserve_case)
+  def parameterize(separator: "-", preserve_case: false, locale: nil)
+    ActiveSupport::Inflector.parameterize(self, separator: separator, preserve_case: preserve_case, locale: locale)
   end
 
   # Creates the name of a table like Rails does for models to table names. This method
diff --git a/activesupport/lib/active_support/inflector/transliterate.rb b/activesupport/lib/active_support/inflector/transliterate.rb
index 0d2a17970f..fe778ff0e7 100644
--- a/activesupport/lib/active_support/inflector/transliterate.rb
+++ b/activesupport/lib/active_support/inflector/transliterate.rb
@@ -51,19 +51,18 @@ module ActiveSupport
     #
     # Now you can have different transliterations for each locale:
     #
-    #   I18n.locale = :en
-    #   transliterate('Jürgen')
+    #   transliterate('Jürgen', locale: :en)
     #   # => "Jurgen"
     #
-    #   I18n.locale = :de
-    #   transliterate('Jürgen')
+    #   transliterate('Jürgen', locale: :de)
     #   # => "Juergen"
-    def transliterate(string, replacement = "?")
+    def transliterate(string, replacement = "?", locale: nil)
       raise ArgumentError, "Can only transliterate strings. Received #{string.class.name}" unless string.is_a?(String)
 
       I18n.transliterate(
         ActiveSupport::Multibyte::Unicode.tidy_bytes(string).unicode_normalize(:nfc),
-        replacement: replacement
+        replacement: replacement,
+        locale: locale
       )
     end
 
@@ -89,9 +88,9 @@ module ActiveSupport
     #  parameterize("^très|Jolie-- ", separator: "_") # => "tres_jolie--"
     #  parameterize("^très_Jolie-- ", separator: ".") # => "tres_jolie--"
     #
-    def parameterize(string, separator: "-", preserve_case: false)
+    def parameterize(string, separator: "-", preserve_case: false, locale: nil)
       # Replace accented chars with their ASCII equivalents.
-      parameterized_string = transliterate(string)
+      parameterized_string = transliterate(string, locale: locale)
 
       # Turn unwanted chars into the separator.
       parameterized_string.gsub!(/[^a-z0-9\-_]+/i, separator)
diff --git a/activesupport/test/core_ext/string_ext_test.rb b/activesupport/test/core_ext/string_ext_test.rb
index 2468fe3603..4ffa33aa61 100644
--- a/activesupport/test/core_ext/string_ext_test.rb
+++ b/activesupport/test/core_ext/string_ext_test.rb
@@ -206,6 +206,12 @@ class StringInflectionsTest < ActiveSupport::TestCase
     end
   end
 
+  def test_parameterize_with_locale
+    word = "Fünf autos"
+    I18n.backend.store_translations(:de, i18n: { transliterate: { rule: { "ü" => "ue" } } })
+    assert_equal("fuenf-autos", word.parameterize(locale: :de))
+  end
+
   def test_humanize
     UnderscoreToHuman.each do |underscore, human|
       assert_equal(human, underscore.humanize)
diff --git a/activesupport/test/inflector_test.rb b/activesupport/test/inflector_test.rb
index c3e1faff5d..ddf765a220 100644
--- a/activesupport/test/inflector_test.rb
+++ b/activesupport/test/inflector_test.rb
@@ -304,6 +304,12 @@ class InflectorTest < ActiveSupport::TestCase
     end
   end
 
+  def test_parameterize_with_locale
+    word = "Fünf autos"
+    I18n.backend.store_translations(:de, i18n: { transliterate: { rule: { "ü" => "ue" } } })
+    assert_equal("fuenf-autos", ActiveSupport::Inflector.parameterize(word, locale: :de))
+  end
+
   def test_classify
     ClassNameToTableName.each do |class_name, table_name|
       assert_equal(class_name, ActiveSupport::Inflector.classify(table_name))
diff --git a/activesupport/test/transliterate_test.rb b/activesupport/test/transliterate_test.rb
index 7d19447598..9e29a93ea0 100644
--- a/activesupport/test/transliterate_test.rb
+++ b/activesupport/test/transliterate_test.rb
@@ -30,6 +30,12 @@ class TransliterateTest < ActiveSupport::TestCase
     I18n.locale = default_locale
   end
 
+  def test_transliterate_respects_the_locale_argument
+    char = [117, 776].pack("U*") # "ü" as ASCII "u" plus COMBINING DIAERESIS
+    I18n.backend.store_translations(:de, i18n: { transliterate: { rule: { "ü" => "ue" } } })
+    assert_equal "ue", ActiveSupport::Inflector.transliterate(char, locale: :de)
+  end
+
   def test_transliterate_should_allow_a_custom_replacement_char
     assert_equal "a*b", ActiveSupport::Inflector.transliterate("a索b", "*")
   end