Avoid redundant attribute_alias? before attribute_alias

If we want to get alias resolved attribute finally, we can use
`attribute_alias` directly.

For that purpose, avoiding redundant `attribute_alias?` makes alias
attribute access 40% faster.

https://gist.github.com/kamipo/e427f080a27b46f50bc508fae3612a0e

Before (2c0729d8):

```
Warming up --------------------------------------
          user['id']   102.668k i/100ms
      user['new_id']    80.660k i/100ms
        user['name']    99.368k i/100ms
    user['new_name']    81.626k i/100ms
Calculating -------------------------------------
          user['id']      1.431M (± 4.0%) i/s -      7.187M in   5.031985s
      user['new_id']      1.042M (± 4.2%) i/s -      5.243M in   5.039858s
        user['name']      1.406M (± 5.6%) i/s -      7.055M in   5.036743s
    user['new_name']      1.074M (± 3.6%) i/s -      5.387M in   5.024152s
```

After (this change):

```
Warming up --------------------------------------
          user['id']   109.775k i/100ms
      user['new_id']   103.303k i/100ms
        user['name']   105.988k i/100ms
    user['new_name']    99.618k i/100ms
Calculating -------------------------------------
          user['id']      1.520M (± 6.7%) i/s -      7.574M in   5.011496s
      user['new_id']      1.485M (± 6.2%) i/s -      7.438M in   5.036252s
        user['name']      1.538M (± 5.4%) i/s -      7.737M in   5.049765s
    user['new_name']      1.516M (± 4.6%) i/s -      7.571M in   5.007293s
```

activemodel/lib/active_model/attributes.rb

@@ -116,22 +116,17 @@ module ActiveModel
     private
 
       def write_attribute(attr_name, value)
-        name = if self.class.attribute_alias?(attr_name)
+        name = attr_name.to_s
-          self.class.attribute_alias(attr_name).to_s
+        name = self.class.attribute_aliases[name] || name
-        else
-          attr_name.to_s
-        end
 
         @attributes.write_from_user(name, value)
         value
       end
 
       def attribute(attr_name)
-        name = if self.class.attribute_alias?(attr_name)
+        name = attr_name.to_s
-          self.class.attribute_alias(attr_name).to_s
+        name = self.class.attribute_aliases[name] || name
-        else
+
-          attr_name.to_s
-        end
         @attributes.fetch_value(name)
       end
 

activerecord/lib/active_record/attribute_methods/dirty.rb

@@ -167,12 +167,8 @@ module ActiveRecord
         end
 
         def write_attribute_without_type_cast(attr_name, value)
-          name = attr_name.to_s
+          result = super
-          if self.class.attribute_alias?(name)
+          clear_attribute_change(attr_name)
-            name = self.class.attribute_alias(name)
-          end
-          result = super(name, value)
-          clear_attribute_change(name)
           result
         end
 

activerecord/lib/active_record/attribute_methods/read.rb

@@ -27,9 +27,7 @@ module ActiveRecord
       # to a date object, like Date.new(2004, 12, 12)).
       def read_attribute(attr_name, &block)
         name = attr_name.to_s
-        if self.class.attribute_alias?(name)
+        name = self.class.attribute_aliases[name] || name
-          name = self.class.attribute_alias(name)
-        end
 
         name = @primary_key if name == "id" && @primary_key
         _read_attribute(name, &block)

activerecord/lib/active_record/attribute_methods/write.rb

@@ -31,9 +31,7 @@ module ActiveRecord
       # turned into +nil+.
       def write_attribute(attr_name, value)
         name = attr_name.to_s
-        if self.class.attribute_alias?(name)
+        name = self.class.attribute_aliases[name] || name
-          name = self.class.attribute_alias(name)
-        end
 
         name = @primary_key if name == "id" && @primary_key
         _write_attribute(name, value)

activerecord/lib/active_record/core.rb

@@ -268,7 +268,8 @@ module ActiveRecord
       end
 
       def arel_attribute(name, table = arel_table) # :nodoc:
-        name = attribute_alias(name) if attribute_alias?(name)
+        name = name.to_s
+        name = attribute_aliases[name] || name
         table[name]
       end
 

activerecord/lib/active_record/persistence.rb

@@ -664,8 +664,13 @@ module ActiveRecord
       raise ActiveRecordError, "cannot update a new record" if new_record?
       raise ActiveRecordError, "cannot update a destroyed record" if destroyed?
 
+      attributes = attributes.transform_keys do |key|
+        name = key.to_s
+        self.class.attribute_aliases[name] || name
+      end
+
       attributes.each_key do |key|
-        verify_readonly_attribute(key.to_s)
+        verify_readonly_attribute(key)
       end
 
       id_in_database = self.id_in_database
@@ -853,7 +858,7 @@ module ActiveRecord
 
       attribute_names = timestamp_attributes_for_update_in_model
       attribute_names |= names.map!(&:to_s).map! { |name|
-        self.class.attribute_alias?(name) ? self.class.attribute_alias(name) : name
+        self.class.attribute_aliases[name] || name
       }
 
       unless attribute_names.empty?

activerecord/lib/active_record/relation/query_methods.rb

@@ -1178,7 +1178,7 @@ module ActiveRecord
       end
 
       def arel_column(field)
-        field = klass.attribute_alias(field) if klass.attribute_alias?(field)
+        field = klass.attribute_aliases[field] || field
         from = from_clause.name || from_clause.value
 
         if klass.columns_hash.key?(field) && (!from || table_name_matches?(from))

activerecord/lib/active_record/table_metadata.rb

@@ -12,9 +12,9 @@ module ActiveRecord
 
     def resolve_column_aliases(hash)
       new_hash = hash.dup
-      hash.each do |key, _|
+      hash.each_key do |key|
-        if (key.is_a?(Symbol)) && klass.attribute_alias?(key)
+        if key.is_a?(Symbol) && new_key = klass.attribute_aliases[key.to_s]
-          new_hash[klass.attribute_alias(key)] = new_hash.delete(key)
+          new_hash[new_key] = new_hash.delete(key)
         end
       end
       new_hash

activerecord/test/models/post.rb

@@ -323,8 +323,8 @@ class FakeKlass
       "posts"
     end
 
-    def attribute_alias?(name)
+    def attribute_aliases
-      false
+      {}
     end
 
     def sanitize_sql(sql)