1 files changed, 21 insertions, 0 deletions
diff --git a/config/initializers/mysql_set_length_for_binary_indexes.rb b/config/initializers/mysql_set_length_for_binary_indexes.rb
new file mode 100644
index 00000000000..de0bc5322aa
--- /dev/null
+++ b/config/initializers/mysql_set_length_for_binary_indexes.rb
@@ -0,0 +1,21 @@
+# This patches ActiveRecord so indexes for binary columns created using the
+# MySQL adapter apply a length of 20. Otherwise MySQL can't create an index on
+# binary columns.
+
+module MysqlSetLengthForBinaryIndex
+  def add_index(table_name, column_names, options = {})
+    Array(column_names).each do |column_name|
+      column = ActiveRecord::Base.connection.columns(table_name).find { |c| c.name == column_name }
+
+      if column&.type == :binary
+        options[:length] = 20
+      end
+    end
+
+    super(table_name, column_names, options)
+  end
+end
+
+if defined?(ActiveRecord::ConnectionAdapters::Mysql2Adapter)
+  ActiveRecord::ConnectionAdapters::Mysql2Adapter.send(:prepend, MysqlSetLengthForBinaryIndex)
+end