Prefer no allocation `start/end_with?` over `String#[] ==`

actionview/lib/action_view/dependency_tracker.rb

@@ -170,7 +170,7 @@ def resolve_directories(wildcard_dependencies)
         def explicit_dependencies
           dependencies = source.scan(EXPLICIT_DEPENDENCY).flatten.uniq
 
-          wildcards, explicits = dependencies.partition { |dependency| dependency[-1] == "*" }
+          wildcards, explicits = dependencies.partition { |dependency| dependency.end_with?("*") }
 
           (explicits + resolve_directories(wildcards)).uniq
         end

actionview/lib/action_view/renderer/abstract_renderer.rb

@@ -46,7 +46,7 @@ def local_variable(path)
             as.to_sym
           else
             begin
-              base = path[-1] == "/" ? "" : File.basename(path)
+              base = path.end_with?("/") ? "" : File.basename(path)
               raise_invalid_identifier(path) unless base =~ /\A_?(.*?)(?:\.\w+)*\z/
               $1.to_sym
             end

actionview/lib/action_view/template.rb

@@ -138,7 +138,7 @@ def initialize(source, identifier, handler, format: nil, variant: nil, locals: n
       @virtual_path      = virtual_path
 
       @variable = if @virtual_path
-        base = @virtual_path[-1] == "/" ? "" : ::File.basename(@virtual_path)
+        base = @virtual_path.end_with?("/") ? "" : ::File.basename(@virtual_path)
         base =~ /\A_?(.*?)(?:\.\w+)*\z/
         $1.to_sym
       end

activemodel/README.rdoc

@@ -200,7 +200,7 @@ behavior out of the box:
       attr_accessor :first_name, :last_name
 
       validates_each :first_name, :last_name do |record, attr, value|
-        record.errors.add attr, 'starts with z.' if value.to_s[0] == ?z
+        record.errors.add attr, "starts with z." if value.start_with?("z")
       end
     end
 

activemodel/lib/active_model/validations.rb

@@ -15,7 +15,7 @@ module ActiveModel
   #     attr_accessor :first_name, :last_name
   #
   #     validates_each :first_name, :last_name do |record, attr, value|
-  #       record.errors.add attr, 'starts with z.' if value.to_s[0] == ?z
+  #       record.errors.add attr, "starts with z." if value.start_with?("z")
   #     end
   #   end
   #
@@ -61,7 +61,7 @@ module ClassMethods
       #     attr_accessor :first_name, :last_name
       #
       #     validates_each :first_name, :last_name, allow_blank: true do |record, attr, value|
-      #       record.errors.add attr, 'starts with z.' if value.to_s[0] == ?z
+      #       record.errors.add attr, "starts with z." if value.start_with?("z")
       #     end
       #   end
       #

activerecord/lib/active_record/connection_adapters/postgresql/oid/legacy_point.rb

@@ -14,7 +14,7 @@ def type
           def cast(value)
             case value
             when ::String
-              if value[0] == "(" && value[-1] == ")"
+              if value.start_with?("(") && value.end_with?(")")
                 value = value[1...-1]
               end
               cast(value.split(","))

activerecord/lib/active_record/connection_adapters/postgresql/oid/point.rb

@@ -18,7 +18,7 @@ def cast(value)
             when ::String
               return if value.blank?
 
-              if value[0] == "(" && value[-1] == ")"
+              if value.start_with?("(") && value.end_with?(")")
                 value = value[1...-1]
               end
               x, y = value.split(",")

activerecord/lib/active_record/connection_adapters/postgresql/oid/range.rb

@@ -67,12 +67,12 @@ def type_cast_single_for_database(value)
             end
 
             def extract_bounds(value)
-              from, to = value[1..-2].split(",")
+              from, to = value[1..-2].split(",", 2)
               {
-                from:          (value[1] == "," || from == "-infinity") ? infinity(negative: true) : from,
-                to:            (value[-2] == "," || to == "infinity") ? infinity : to,
-                exclude_start: (value[0] == "("),
-                exclude_end:   (value[-1] == ")")
+                from:          (from == "" || from == "-infinity") ? infinity(negative: true) : from,
+                to:            (to == "" || to == "infinity") ? infinity : to,
+                exclude_start: value.start_with?("("),
+                exclude_end:   value.end_with?(")")
               }
             end
 

activesupport/lib/active_support/array_inquirer.rb

 # frozen_string_literal: true
 
+require "active_support/core_ext/symbol/starts_ends_with"
+
 module ActiveSupport
   # Wrapping an array in an +ArrayInquirer+ gives a friendlier way to check
   # its string-like contents:
@@ -34,11 +36,11 @@ def any?(*candidates)
 
     private
       def respond_to_missing?(name, include_private = false)
-        (name[-1] == "?") || super
+        name.end_with?("?") || super
       end
 
       def method_missing(name, *args)
-        if name[-1] == "?"
+        if name.end_with?("?")
           any?(name[0..-2])
         else
           super

activesupport/lib/active_support/string_inquirer.rb

 # frozen_string_literal: true
 
+require "active_support/core_ext/symbol/starts_ends_with"
+
 module ActiveSupport
   # Wrapping a string in this class gives you a prettier way to test
   # for equality. The value returned by <tt>Rails.env</tt> is wrapped
@@ -19,11 +21,11 @@ module ActiveSupport
   class StringInquirer < String
     private
       def respond_to_missing?(method_name, include_private = false)
-        (method_name[-1] == "?") || super
+        method_name.end_with?("?") || super
       end
 
       def method_missing(method_name, *arguments)
-        if method_name[-1] == "?"
+        if method_name.end_with?("?")
           self == method_name[0..-2]
         else
           super

railties/lib/rails/source_annotation_extractor.rb

@@ -109,7 +109,7 @@ def find_in(dir)
       results = {}
 
       Dir.glob("#{dir}/*") do |item|
-        next if File.basename(item)[0] == ?.
+        next if File.basename(item).start_with?(".")
 
         if File.directory?(item)
           results.update(find_in(item))