ActiveSupport Hash optimizations [#2902 state:resolved]

Signed-off-by: Carl Lerche <carllerche@mac.com>

activesupport/lib/active_support/core_ext/hash/deep_merge.rb

@@ -4,7 +4,7 @@ class Hash
     merge(other_hash) do |key, oldval, newval|
       oldval = oldval.to_hash if oldval.respond_to?(:to_hash)
       newval = newval.to_hash if newval.respond_to?(:to_hash)
-      oldval.class.to_s == 'Hash' && newval.class.to_s == 'Hash' ? oldval.deep_merge(newval) : newval
+      oldval.is_a?( Hash ) && newval.is_a?( Hash ) ? oldval.deep_merge(newval) : newval
     end
   end
 

activesupport/lib/active_support/core_ext/hash/diff.rb

@@ -8,6 +8,6 @@ class Hash
   #   {}.diff(1 => 2)               # => {1 => 2}
   #   {1 => 2, 3 => 4}.diff(1 => 2) # => {3 => 4}
   def diff(h2)
-    dup.delete_if { |k, v| h2[k] == v }.merge(h2.dup.delete_if { |k, v| has_key?(k) })
+    dup.delete_if { |k, v| h2[k] == v }.merge!(h2.dup.delete_if { |k, v| has_key?(k) })
   end
 end

activesupport/lib/active_support/core_ext/hash/reverse_merge.rb

@@ -21,7 +21,7 @@ class Hash
   # Performs the opposite of <tt>merge</tt>, with the keys and values from the first hash taking precedence over the second.
   # Modifies the receiver in place.
   def reverse_merge!(other_hash)
-    replace(reverse_merge(other_hash))
+    merge!( other_hash ){|k,o,n| o }
   end
 
   alias_method :reverse_update, :reverse_merge!

activesupport/lib/active_support/hash_with_indifferent_access.rb

@@ -98,6 +98,10 @@ module ActiveSupport
       super other_hash.with_indifferent_access
     end
 
+    def reverse_merge!(other_hash)
+      replace(reverse_merge( other_hash ))
+    end
+
     # Removes a specified key from the hash.
     def delete(key)
       super(convert_key(key))
@@ -109,7 +113,7 @@ module ActiveSupport
 
     # Convert to a Hash with String keys.
     def to_hash
-      Hash.new(default).merge(self)
+      Hash.new(default).merge!(self)
     end
 
     protected