Reduce string objects by using \ instead of + or << for concatenating strings

(I personally prefer writing one string in one line no matter how long it is, though)

actioncable/lib/action_cable/connection/client_socket.rb

@@ -90,8 +90,8 @@ def close(code = nil, reason = nil)
         reason ||= ""
 
         unless code == 1000 || (code >= 3000 && code <= 4999)
-          raise ArgumentError, "Failed to execute 'close' on WebSocket: " +
-                               "The code must be either 1000, or between 3000 and 4999. " +
+          raise ArgumentError, "Failed to execute 'close' on WebSocket: " \
+                               "The code must be either 1000, or between 3000 and 4999. " \
                                "#{code} is neither."
         end
 

actionmailer/lib/action_mailer/test_case.rb

@@ -4,8 +4,8 @@
 module ActionMailer
   class NonInferrableMailerError < ::StandardError
     def initialize(name)
-      super "Unable to determine the mailer to test from #{name}. " +
-        "You'll need to specify it using tests YourMailer in your " +
+      super "Unable to determine the mailer to test from #{name}. " \
+        "You'll need to specify it using tests YourMailer in your " \
         "test case definition"
     end
   end

actionmailer/test/mail_helper_test.rb

@@ -2,11 +2,11 @@
 
 class HelperMailer < ActionMailer::Base
   def use_mail_helper
-    @text = "But soft! What light through yonder window breaks? It is the east, " +
-            "and Juliet is the sun. Arise, fair sun, and kill the envious moon, " +
-            "which is sick and pale with grief that thou, her maid, art far more " +
-            "fair than she. Be not her maid, for she is envious! Her vestal " +
-            "livery is but sick and green, and none but fools do wear it. Cast " +
+    @text = "But soft! What light through yonder window breaks? It is the east, " \
+            "and Juliet is the sun. Arise, fair sun, and kill the envious moon, " \
+            "which is sick and pale with grief that thou, her maid, art far more " \
+            "fair than she. Be not her maid, for she is envious! Her vestal " \
+            "livery is but sick and green, and none but fools do wear it. Cast " \
             "it off!"
 
     mail_with_defaults do |format|

actionpack/lib/action_dispatch/middleware/cookies.rb

@@ -572,7 +572,7 @@ def initialize(parent_jar)
         super
 
         if ActiveSupport::LegacyKeyGenerator === key_generator
-          raise "You didn't set secrets.secret_key_base, which is required for this cookie jar. " +
+          raise "You didn't set secrets.secret_key_base, which is required for this cookie jar. " \
             "Read the upgrade documentation to learn more about this new config option."
         end
 

actionpack/lib/action_dispatch/middleware/remote_ip.rb

@@ -131,8 +131,8 @@ def calculate_ip
         should_check_ip = @check_ip && client_ips.last && forwarded_ips.last
         if should_check_ip && !forwarded_ips.include?(client_ips.last)
           # We don't know which came from the proxy, and which from the user
-          raise IpSpoofAttackError, "IP spoofing attack?! " +
-            "HTTP_CLIENT_IP=#{@req.client_ip.inspect} " +
+          raise IpSpoofAttackError, "IP spoofing attack?! " \
+            "HTTP_CLIENT_IP=#{@req.client_ip.inspect} " \
             "HTTP_X_FORWARDED_FOR=#{@req.x_forwarded_for.inspect}"
         end
 

actionpack/lib/action_dispatch/middleware/session/abstract_store.rb

@@ -8,8 +8,8 @@ module ActionDispatch
   module Session
     class SessionRestoreError < StandardError #:nodoc:
       def initialize
-        super("Session contains objects whose class definition isn't available.\n" +
-          "Remember to require the classes for all objects kept in the session.\n" +
+        super("Session contains objects whose class definition isn't available.\n" \
+          "Remember to require the classes for all objects kept in the session.\n" \
           "(Original exception: #{$!.message} [#{$!.class}])\n")
         set_backtrace $!.backtrace
       end

actionpack/lib/action_dispatch/testing/integration.rb

@@ -145,8 +145,8 @@ def reset!
 
         self.host        = DEFAULT_HOST
         self.remote_addr = "127.0.0.1"
-        self.accept      = "text/xml,application/xml,application/xhtml+xml," +
-                           "text/html;q=0.9,text/plain;q=0.8,image/png," +
+        self.accept      = "text/xml,application/xml,application/xhtml+xml," \
+                           "text/html;q=0.9,text/plain;q=0.8,image/png," \
                            "*/*;q=0.5"
 
         unless defined? @named_routes_configured

actionpack/test/controller/filters_test.rb

@@ -704,7 +704,7 @@ def test_having_properties_in_around_action
 
   def test_prepending_and_appending_around_action
     test_process(MixedFilterController)
-    assert_equal " before aroundfilter  before procfilter  before appended aroundfilter " +
+    assert_equal " before aroundfilter  before procfilter  before appended aroundfilter " \
                  " after appended aroundfilter  after procfilter  after aroundfilter ",
                  MixedFilterController.execution_log
   end

actionpack/test/dispatch/session/cookie_store_test.rb

@@ -175,7 +175,7 @@ def test_doesnt_write_session_cookie_if_session_is_not_accessed
 
   def test_doesnt_write_session_cookie_if_session_is_unchanged
     with_test_route_set do
-      cookies[SessionKey] = "BAh7BjoIZm9vIghiYXI%3D--" +
+      cookies[SessionKey] = "BAh7BjoIZm9vIghiYXI%3D--" \
         "fef868465920f415f2c0652d6910d3af288a0367"
       get "/no_session_access"
       assert_response :success

actionview/lib/action_view/helpers/url_helper.rb

@@ -35,7 +35,7 @@ def url_for(options = nil) # :nodoc:
         when :back
           _back_url
         else
-          raise ArgumentError, "arguments passed to url_for can't be handled. Please require " +
+          raise ArgumentError, "arguments passed to url_for can't be handled. Please require " \
                                "routes or provide your own implementation"
         end
       end

actionview/lib/action_view/renderer/partial_renderer.rb

@@ -532,11 +532,11 @@ def retrieve_variable(path, as)
         [variable, variable_counter, variable_iteration]
       end
 
-      IDENTIFIER_ERROR_MESSAGE = "The partial name (%s) is not a valid Ruby identifier; " +
+      IDENTIFIER_ERROR_MESSAGE = "The partial name (%s) is not a valid Ruby identifier; " \
                                  "make sure your partial name starts with underscore."
 
-      OPTION_AS_ERROR_MESSAGE  = "The value (%s) of the option `as` is not a valid Ruby identifier; " +
-                                 "make sure it starts with lowercase letter, " +
+      OPTION_AS_ERROR_MESSAGE  = "The value (%s) of the option `as` is not a valid Ruby identifier; " \
+                                 "make sure it starts with lowercase letter, " \
                                  "and is followed by any combination of letters, numbers and underscores."
 
       def raise_invalid_identifier(path)

actionview/lib/action_view/template/handlers/builder.rb

@@ -7,7 +7,7 @@ class Builder
 
       def call(template)
         require_engine
-        "xml = ::Builder::XmlMarkup.new(:indent => 2);" +
+        "xml = ::Builder::XmlMarkup.new(:indent => 2);" \
           "self.output_buffer = xml.target!;" +
           template.source +
           ";xml.target!;"

actionview/test/activerecord/form_helper_activerecord_test.rb

@@ -45,7 +45,7 @@ def test_nested_fields_for_with_child_index_option_override_on_a_nested_attribut
     end
 
     expected = whole_form("/developers/123", "edit_developer_123", "edit_developer", method: "patch") do
-      '<input id="developer_projects_attributes_abc_name" name="developer[projects_attributes][abc][name]" type="text" value="project #321" />' +
+      '<input id="developer_projects_attributes_abc_name" name="developer[projects_attributes][abc][name]" type="text" value="project #321" />' \
           '<input id="developer_projects_attributes_abc_id" name="developer[projects_attributes][abc][id]" type="hidden" value="321" />'
     end
 

actionview/test/template/form_options_helper_test.rb

@@ -393,30 +393,30 @@ def test_optgroups_with_with_options_with_hash
 
   def test_time_zone_options_no_params
     opts = time_zone_options_for_select
-    assert_dom_equal "<option value=\"A\">A</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"D\">D</option>\n" +
+    assert_dom_equal "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\">D</option>\n" \
                  "<option value=\"E\">E</option>",
                  opts
   end
 
   def test_time_zone_options_with_selected
     opts = time_zone_options_for_select("D")
-    assert_dom_equal "<option value=\"A\">A</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"D\" selected=\"selected\">D</option>\n" +
+    assert_dom_equal "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
                  "<option value=\"E\">E</option>",
                  opts
   end
 
   def test_time_zone_options_with_unknown_selected
     opts = time_zone_options_for_select("K")
-    assert_dom_equal "<option value=\"A\">A</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"D\">D</option>\n" +
+    assert_dom_equal "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\">D</option>\n" \
                  "<option value=\"E\">E</option>",
                  opts
   end
@@ -424,11 +424,11 @@ def test_time_zone_options_with_unknown_selected
   def test_time_zone_options_with_priority_zones
     zones = [ ActiveSupport::TimeZone.new("B"), ActiveSupport::TimeZone.new("E") ]
     opts = time_zone_options_for_select(nil, zones)
-    assert_dom_equal "<option value=\"B\">B</option>\n" +
-                 "<option value=\"E\">E</option>" +
-                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
+    assert_dom_equal "<option value=\"B\">B</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
                  "<option value=\"D\">D</option>",
                  opts
   end
@@ -436,11 +436,11 @@ def test_time_zone_options_with_priority_zones
   def test_time_zone_options_with_selected_priority_zones
     zones = [ ActiveSupport::TimeZone.new("B"), ActiveSupport::TimeZone.new("E") ]
     opts = time_zone_options_for_select("E", zones)
-    assert_dom_equal "<option value=\"B\">B</option>\n" +
-                 "<option value=\"E\" selected=\"selected\">E</option>" +
-                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
+    assert_dom_equal "<option value=\"B\">B</option>\n" \
+                 "<option value=\"E\" selected=\"selected\">E</option>" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
                  "<option value=\"D\">D</option>",
                  opts
   end
@@ -448,11 +448,11 @@ def test_time_zone_options_with_selected_priority_zones
   def test_time_zone_options_with_unselected_priority_zones
     zones = [ ActiveSupport::TimeZone.new("B"), ActiveSupport::TimeZone.new("E") ]
     opts = time_zone_options_for_select("C", zones)
-    assert_dom_equal "<option value=\"B\">B</option>\n" +
-                 "<option value=\"E\">E</option>" +
-                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"C\" selected=\"selected\">C</option>\n" +
+    assert_dom_equal "<option value=\"B\">B</option>\n" \
+                 "<option value=\"E\">E</option>" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"C\" selected=\"selected\">C</option>\n" \
                  "<option value=\"D\">D</option>",
                  opts
   end
@@ -1031,12 +1031,12 @@ def test_collection_select_with_proc_for_text_method
   def test_time_zone_select
     @firm = Firm.new("D")
     html = time_zone_select("firm", "time_zone")
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"D\" selected=\"selected\">D</option>\n" +
-                 "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
                  "</select>",
                  html
   end
@@ -1049,12 +1049,12 @@ def test_time_zone_select_under_fields_for
     end
 
     assert_dom_equal(
-      "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" +
-      "<option value=\"A\">A</option>\n" +
-      "<option value=\"B\">B</option>\n" +
-      "<option value=\"C\">C</option>\n" +
-      "<option value=\"D\" selected=\"selected\">D</option>\n" +
-      "<option value=\"E\">E</option>" +
+      "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+      "<option value=\"A\">A</option>\n" \
+      "<option value=\"B\">B</option>\n" \
+      "<option value=\"C\">C</option>\n" \
+      "<option value=\"D\" selected=\"selected\">D</option>\n" \
+      "<option value=\"E\">E</option>" \
       "</select>",
       output_buffer
     )
@@ -1068,12 +1068,12 @@ def test_time_zone_select_under_fields_for_with_index
     end
 
     assert_dom_equal(
-      "<select id=\"firm_305_time_zone\" name=\"firm[305][time_zone]\">" +
-      "<option value=\"A\">A</option>\n" +
-      "<option value=\"B\">B</option>\n" +
-      "<option value=\"C\">C</option>\n" +
-      "<option value=\"D\" selected=\"selected\">D</option>\n" +
-      "<option value=\"E\">E</option>" +
+      "<select id=\"firm_305_time_zone\" name=\"firm[305][time_zone]\">" \
+      "<option value=\"A\">A</option>\n" \
+      "<option value=\"B\">B</option>\n" \
+      "<option value=\"C\">C</option>\n" \
+      "<option value=\"D\" selected=\"selected\">D</option>\n" \
+      "<option value=\"E\">E</option>" \
       "</select>",
       output_buffer
     )
@@ -1088,12 +1088,12 @@ def @firm.to_param; 305; end
     end
 
     assert_dom_equal(
-      "<select id=\"firm_305_time_zone\" name=\"firm[305][time_zone]\">" +
-      "<option value=\"A\">A</option>\n" +
-      "<option value=\"B\">B</option>\n" +
-      "<option value=\"C\">C</option>\n" +
-      "<option value=\"D\" selected=\"selected\">D</option>\n" +
-      "<option value=\"E\">E</option>" +
+      "<select id=\"firm_305_time_zone\" name=\"firm[305][time_zone]\">" \
+      "<option value=\"A\">A</option>\n" \
+      "<option value=\"B\">B</option>\n" \
+      "<option value=\"C\">C</option>\n" \
+      "<option value=\"D\" selected=\"selected\">D</option>\n" \
+      "<option value=\"E\">E</option>" \
       "</select>",
       output_buffer
     )
@@ -1102,13 +1102,13 @@ def @firm.to_param; 305; end
   def test_time_zone_select_with_blank
     @firm = Firm.new("D")
     html = time_zone_select("firm", "time_zone", nil, include_blank: true)
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" +
-                 "<option value=\"\"></option>\n" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"D\" selected=\"selected\">D</option>\n" +
-                 "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"\"></option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
                  "</select>",
                  html
   end
@@ -1116,13 +1116,13 @@ def test_time_zone_select_with_blank
   def test_time_zone_select_with_blank_as_string
     @firm = Firm.new("D")
     html = time_zone_select("firm", "time_zone", nil, include_blank: "No Zone")
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" +
-                 "<option value=\"\">No Zone</option>\n" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"D\" selected=\"selected\">D</option>\n" +
-                 "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"\">No Zone</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
                  "</select>",
                  html
   end
@@ -1131,12 +1131,12 @@ def test_time_zone_select_with_style
     @firm = Firm.new("D")
     html = time_zone_select("firm", "time_zone", nil, {},
       "style" => "color: red")
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\" style=\"color: red\">" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"D\" selected=\"selected\">D</option>\n" +
-                 "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\" style=\"color: red\">" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
                  "</select>",
                  html
     assert_dom_equal html, time_zone_select("firm", "time_zone", nil, {},
@@ -1147,13 +1147,13 @@ def test_time_zone_select_with_blank_and_style
     @firm = Firm.new("D")
     html = time_zone_select("firm", "time_zone", nil,
       { include_blank: true }, "style" => "color: red")
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\" style=\"color: red\">" +
-                 "<option value=\"\"></option>\n" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"D\" selected=\"selected\">D</option>\n" +
-                 "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\" style=\"color: red\">" \
+                 "<option value=\"\"></option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
                  "</select>",
                  html
     assert_dom_equal html, time_zone_select("firm", "time_zone", nil,
@@ -1164,13 +1164,13 @@ def test_time_zone_select_with_blank_as_string_and_style
     @firm = Firm.new("D")
     html = time_zone_select("firm", "time_zone", nil,
       { include_blank: "No Zone" }, "style" => "color: red")
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\" style=\"color: red\">" +
-                 "<option value=\"\">No Zone</option>\n" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"D\" selected=\"selected\">D</option>\n" +
-                 "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\" style=\"color: red\">" \
+                 "<option value=\"\">No Zone</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
                  "</select>",
                  html
     assert_dom_equal html, time_zone_select("firm", "time_zone", nil,
@@ -1181,13 +1181,13 @@ def test_time_zone_select_with_priority_zones
     @firm = Firm.new("D")
     zones = [ ActiveSupport::TimeZone.new("A"), ActiveSupport::TimeZone.new("D") ]
     html = time_zone_select("firm", "time_zone", zones)
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"D\" selected=\"selected\">D</option>" +
-                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"E\">E</option>" \
                  "</select>",
                  html
   end
@@ -1200,13 +1200,13 @@ def tz.=~(re); %(A D).include?(name) end
     end
 
     html = time_zone_select("firm", "time_zone", /A|D/)
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"D\" selected=\"selected\">D</option>" +
-                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"E\">E</option>" \
                  "</select>",
                  html
   end
@@ -1221,13 +1221,13 @@ def tz.===(zone); raise Exception; end
     end
 
     html = time_zone_select("firm", "time_zone", /A|D/)
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" +
-                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" +
-                 "<option value=\"A\">A</option>\n" +
-                 "<option value=\"B\">B</option>\n" +
-                 "<option value=\"C\">C</option>\n" +
-                 "<option value=\"D\" selected=\"selected\">D</option>\n" +
-                 "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                 "<option value=\"\" disabled=\"disabled\">-------------</option>\n" \
+                 "<option value=\"A\">A</option>\n" \
+                 "<option value=\"B\">B</option>\n" \
+                 "<option value=\"C\">C</option>\n" \
+                 "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                 "<option value=\"E\">E</option>" \
                  "</select>",
                  html
   end
@@ -1237,12 +1237,12 @@ def test_time_zone_select_with_default_time_zone_and_nil_value
     @firm.time_zone = nil
 
     html = time_zone_select("firm", "time_zone", nil, default: "B")
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" +
-                  "<option value=\"A\">A</option>\n" +
-                  "<option value=\"B\" selected=\"selected\">B</option>\n" +
-                  "<option value=\"C\">C</option>\n" +
-                  "<option value=\"D\">D</option>\n" +
-                  "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                  "<option value=\"A\">A</option>\n" \
+                  "<option value=\"B\" selected=\"selected\">B</option>\n" \
+                  "<option value=\"C\">C</option>\n" \
+                  "<option value=\"D\">D</option>\n" \
+                  "<option value=\"E\">E</option>" \
                   "</select>",
                   html
   end
@@ -1251,12 +1251,12 @@ def test_time_zone_select_with_default_time_zone_and_value
     @firm = Firm.new("D")
 
     html = time_zone_select("firm", "time_zone", nil, default: "B")
-    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" +
-                  "<option value=\"A\">A</option>\n" +
-                  "<option value=\"B\">B</option>\n" +
-                  "<option value=\"C\">C</option>\n" +
-                  "<option value=\"D\" selected=\"selected\">D</option>\n" +
-                  "<option value=\"E\">E</option>" +
+    assert_dom_equal "<select id=\"firm_time_zone\" name=\"firm[time_zone]\">" \
+                  "<option value=\"A\">A</option>\n" \
+                  "<option value=\"B\">B</option>\n" \
+                  "<option value=\"C\">C</option>\n" \
+                  "<option value=\"D\" selected=\"selected\">D</option>\n" \
+                  "<option value=\"E\">E</option>" \
                   "</select>",
                   html
   end

actionview/test/template/render_test.rb

@@ -220,15 +220,15 @@ def test_render_partial_with_unicode_text
 
   def test_render_partial_with_invalid_option_as
     e = assert_raises(ArgumentError) { @view.render(partial: "test/partial_only", as: "a-in") }
-    assert_equal "The value (a-in) of the option `as` is not a valid Ruby identifier; " +
-      "make sure it starts with lowercase letter, " +
+    assert_equal "The value (a-in) of the option `as` is not a valid Ruby identifier; " \
+      "make sure it starts with lowercase letter, " \
       "and is followed by any combination of letters, numbers and underscores.", e.message
   end
 
   def test_render_partial_with_hyphen_and_invalid_option_as
     e = assert_raises(ArgumentError) { @view.render(partial: "test/a-in", as: "a-in") }
-    assert_equal "The value (a-in) of the option `as` is not a valid Ruby identifier; " +
-      "make sure it starts with lowercase letter, " +
+    assert_equal "The value (a-in) of the option `as` is not a valid Ruby identifier; " \
+      "make sure it starts with lowercase letter, " \
       "and is followed by any combination of letters, numbers and underscores.", e.message
   end
 
@@ -424,7 +424,7 @@ def test_render_fallbacks_to_erb_for_unknown_types
   end
 
   CustomHandler = lambda do |template|
-    "@output_buffer = ''\n" +
+    "@output_buffer = ''\n" \
       "@output_buffer << 'source: #{template.source.inspect}'\n"
   end
 

actionview/test/template/url_helper_test.rb

@@ -821,7 +821,7 @@ def show
 
   private
     def render_default
-      render inline: "<%= link_to_unless_current('tasks', tasks_path) %>\n" +
+      render inline: "<%= link_to_unless_current('tasks', tasks_path) %>\n" \
         "<%= link_to_unless_current('tasks', tasks_url) %>"
     end
 end

activerecord/lib/active_record/associations/has_one_association.rb

@@ -85,7 +85,7 @@ def remove_target!(method)
 
             if target.persisted? && owner.persisted? && !target.save
               set_owner_attributes(target)
-              raise RecordNotSaved, "Failed to remove the existing associated #{reflection.name}. " +
+              raise RecordNotSaved, "Failed to remove the existing associated #{reflection.name}. " \
                                     "The record failed to save after its foreign key was set to nil."
             end
           end

activerecord/lib/active_record/connection_adapters/abstract_adapter.rb

@@ -176,7 +176,7 @@ def lease
           if @owner == Thread.current
             msg << "it is already leased by the current thread."
           else
-            msg << "it is already in use by a different thread: #{@owner}. " <<
+            msg << "it is already in use by a different thread: #{@owner}. " \
                    "Current thread: #{Thread.current}."
           end
           raise ActiveRecordError, msg
@@ -194,8 +194,8 @@ def schema_cache=(cache)
       def expire
         if in_use?
           if @owner != Thread.current
-            raise ActiveRecordError, "Cannot expire connection, " <<
-              "it is owned by a different thread: #{@owner}. " <<
+            raise ActiveRecordError, "Cannot expire connection, " \
+              "it is owned by a different thread: #{@owner}. " \
               "Current thread: #{Thread.current}."
           end
 

activerecord/lib/active_record/tasks/database_tasks.rb

@@ -267,8 +267,8 @@ def load_seed
         if seed_loader
           seed_loader.load_seed
         else
-          raise "You tried to load seed data, but no seed loader is specified. Please specify seed " +
-                "loader with ActiveRecord::Tasks::DatabaseTasks.seed_loader = your_seed_loader\n" +
+          raise "You tried to load seed data, but no seed loader is specified. Please specify seed " \
+                "loader with ActiveRecord::Tasks::DatabaseTasks.seed_loader = your_seed_loader\n" \
                 "Seed loader should respond to load_seed method"
         end
       end

activerecord/test/cases/adapters/postgresql/connection_test.rb

@@ -156,7 +156,7 @@ def test_reconnection_after_actual_disconnection_with_verify
         secondary_connection.query("select pg_terminate_backend(#{original_connection_pid.first.first})")
         ActiveRecord::Base.connection_pool.checkin(secondary_connection)
       elsif ARTest.config["with_manual_interventions"]
-        puts "Kill the connection now (e.g. by restarting the PostgreSQL " +
+        puts "Kill the connection now (e.g. by restarting the PostgreSQL " \
           'server with the "-m fast" option) and then press enter.'
         $stdin.gets
       else
@@ -175,7 +175,7 @@ def test_reconnection_after_actual_disconnection_with_verify
       new_connection_pid = @connection.query("select pg_backend_pid()")
 
       assert_not_equal original_connection_pid, new_connection_pid,
-        "umm -- looks like you didn't break the connection, because we're still " +
+        "umm -- looks like you didn't break the connection, because we're still " \
         "successfully querying with the same connection pid."
 
       # Repair all fixture connections so other tests won't break.

activerecord/test/cases/associations/has_one_associations_test.rb

@@ -476,7 +476,7 @@ def test_replacement_failure_due_to_existing_record_should_raise_error
 
     assert_equal ships(:black_pearl), pirate.ship
     assert_equal pirate.id, pirate.ship.pirate_id
-    assert_equal "Failed to remove the existing associated ship. " +
+    assert_equal "Failed to remove the existing associated ship. " \
                  "The record failed to save after its foreign key was set to nil.", error.message
   end
 

activerecord/test/cases/connection_pool_test.rb

@@ -399,7 +399,7 @@ def test_concurrent_connection_establishment
             all_threads_in_new_connection.wait
           end
         rescue Timeout::Error
-          flunk "pool unable to establish connections concurrently or implementation has " <<
+          flunk "pool unable to establish connections concurrently or implementation has " \
                 "changed, this test then needs to patch a different :new_connection method"
         ensure
           # clean up the threads

activerecord/test/cases/nested_attributes_with_callbacks_test.rb

@@ -120,14 +120,14 @@ def assert_callbacks_not_called
     assert_assignment_affects_records_in_target(:birds_with_add)
   end
 
-  test("Assignment updates records in target when not loaded" +
+  test("Assignment updates records in target when not loaded" \
        " and callback loads target") do
     assert_not @pirate.birds_with_add_load.loaded?
     @pirate.birds_with_add_load_attributes = update_new_and_destroy_bird_attributes
     assert_assignment_affects_records_in_target(:birds_with_add_load)
   end
 
-  test("Assignment updates records in target when loaded" +
+  test("Assignment updates records in target when loaded" \
        " and callback loads target") do
     @pirate.birds_with_add_load.load_target
     @pirate.birds_with_add_load_attributes = update_new_and_destroy_bird_attributes

activesupport/test/core_ext/string_ext_test.rb

@@ -222,7 +222,7 @@ def test_string_squish
     original = %{\u205f\u3000 A string surrounded by various unicode spaces,
       with tabs(\t\t), newlines(\n\n), unicode nextlines(\u0085\u0085) and many spaces(  ). \u00a0\u2007}
 
-    expected = "A string surrounded by various unicode spaces, " +
+    expected = "A string surrounded by various unicode spaces, " \
       "with tabs( ), newlines( ), unicode nextlines( ) and many spaces( )."
 
     # Make sure squish returns what we expect:

railties/lib/rails/application.rb

@@ -511,7 +511,7 @@ def default_middleware_stack #:nodoc:
 
     def validate_secret_key_config! #:nodoc:
       if secrets.secret_key_base.blank?
-        ActiveSupport::Deprecation.warn "You didn't set `secret_key_base`. " +
+        ActiveSupport::Deprecation.warn "You didn't set `secret_key_base`. " \
           "Read the upgrade documentation to learn more about this new config option."
 
         if secrets.secret_token.blank?

railties/lib/rails/application/bootstrap.rb

@@ -48,8 +48,8 @@ module Bootstrap
           logger = ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(STDERR))
           logger.level = ActiveSupport::Logger::WARN
           logger.warn(
-            "Rails Error: Unable to access log file. Please ensure that #{path} exists and is writable " +
-            "(ie, make it writable for user and group: chmod 0664 #{path}). " +
+            "Rails Error: Unable to access log file. Please ensure that #{path} exists and is writable " \
+            "(ie, make it writable for user and group: chmod 0664 #{path}). " \
             "The log level has been raised to WARN and the output directed to STDERR until the problem is fixed."
           )
           logger

railties/lib/rails/generators/actions/create_migration.rb

@@ -54,8 +54,8 @@ def on_conflict_behavior # :doc:
               say_status :skip, :yellow
             else
               say_status :conflict, :red
-              raise Error, "Another migration is already named #{migration_file_name}: " +
-                "#{existing_migration}. Use --force to replace this migration " +
+              raise Error, "Another migration is already named #{migration_file_name}: " \
+                "#{existing_migration}. Use --force to replace this migration " \
                 "or --skip to ignore conflicted file."
             end
           end

railties/lib/rails/generators/base.rb

@@ -256,8 +256,8 @@ def class_collisions(*class_names)
             last = extract_last_module(nesting)
 
             if last && last.const_defined?(last_name.camelize, false)
-              raise Error, "The name '#{class_name}' is either already used in your application " <<
-                           "or reserved by Ruby on Rails. Please choose an alternative and run "  <<
+              raise Error, "The name '#{class_name}' is either already used in your application " \
+                           "or reserved by Ruby on Rails. Please choose an alternative and run "  \
                            "this generator again."
             end
           end

railties/lib/rails/generators/rails/plugin/plugin_generator.rb

@@ -186,7 +186,7 @@ class PluginGenerator < AppBase # :nodoc:
                                   desc: "Skip gemspec file"
 
       class_option :skip_gemfile_entry, type: :boolean, default: false,
-                                        desc: "If creating plugin in application's directory " +
+                                        desc: "If creating plugin in application's directory " \
                                                  "skip adding entry to Gemfile"
 
       class_option :api,          type: :boolean, default: false,