Refactor index algorithm lookup so that it only builds the available options once

This way the available options are only built for actually fetching the
algorithm in case the option is given.

The options are going to be necessary a second time only in case the option
is given but does not exist, which is supposed to be due to a typo or
something like that, so no problem.

1 files changed, 4 insertions, 4 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
index c9eb9ee2f7..9c0c4e3ef0 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -774,10 +774,10 @@ module ActiveRecord
             index_name = options[:name].to_s if options.key?(:name)
             max_index_length = options.fetch(:internal, false) ? index_name_length : allowed_index_name_length
 
-            if index_algorithms.key?(options[:algorithm])
-              algorithm = index_algorithms[options[:algorithm]]
-            elsif options[:algorithm].present?
-              raise ArgumentError.new("Algorithm must be one of the following: #{index_algorithms.keys.map(&:inspect).join(', ')}")
+            if options.key?(:algorithm)
+              algorithm = index_algorithms.fetch(options[:algorithm]) {
+                raise ArgumentError.new("Algorithm must be one of the following: #{index_algorithms.keys.map(&:inspect).join(', ')}")
+              }
             end
 
             using = "USING #{options[:using]}" if options[:using].present?