Use builtin Rails index_exists? for indices (#6293)

app/lib/index_migration_helpers.rb

@@ -1,19 +0,0 @@
-module IndexMigrationHelpers
-  def add_index_if_missing(table_name, column_name, options = {})
-    columns = Array(column_name)
-    if options.key?(:name) && indexes(table_name).none? { |idx| idx.name == options[:name] }
-      add_index(table_name, column_name, options)
-    elsif indexes(table_name).none? { |idx| idx.columns.map(&:to_sym) == columns }
-      add_index(table_name, column_name, options)
-    end
-  end
-
-  def remove_index_if_exists(table_name, options = {})
-    columns = Array(options[:column])
-    if options.key?(:name) && indexes(table_name).any? { |idx| idx.name == options[:name] }
-      remove_index(table_name, options)
-    elsif indexes(table_name).any? { |idx| idx.columns.map(&:to_sym) == columns }
-      remove_index(table_name, options)
-    end
-  end
-end

config/initializers/strong_migrations.rb

@@ -1,5 +1,8 @@
 # https://github.com/ankane/strong_migrations#existing-migrations
 StrongMigrations.start_after = 20_200_106_074_859
 
+# https://github.com/ankane/strong_migrations#removing-an-index
+StrongMigrations.enable_check(:remove_index)
+
 # https://github.com/ankane/strong_migrations#target-version
 StrongMigrations.target_postgresql_version = 11

db/migrate/20200224153122_add_title_website_url_indexes_to_podcast_episodes.rb

@@ -1,14 +1,23 @@
 class AddTitleWebsiteUrlIndexesToPodcastEpisodes < ActiveRecord::Migration[5.2]
   disable_ddl_transaction!
-  include IndexMigrationHelpers
 
   def up
-    add_index_if_missing(:podcast_episodes, :title, algorithm: :concurrently)
-    add_index_if_missing(:podcast_episodes, :website_url, algorithm: :concurrently)
+    unless index_exists?(:podcast_episodes, :title)
+      add_index :podcast_episodes, :title, algorithm: :concurrently
+    end
+
+    unless index_exists?(:podcast_episodes, :website_url)
+      add_index :podcast_episodes, :website_url, algorithm: :concurrently
+    end
   end
 
   def down
-    remove_index_if_exists(:podcast_episodes, column: :title, algorithm: :concurrently)
-    remove_index_if_exists(:podcast_episodes, column: :website_url, algorithm: :concurrently)
+    if index_exists?(:podcast_episodes, :title)
+      remove_index :podcast_episodes, column: :title, algorithm: :concurrently
+    end
+
+    if index_exists?(:podcast_episodes, :website_url)
+      remove_index :podcast_episodes, column: :website_url, algorithm: :concurrently
+    end
   end
 end