Fix migration script not being able to run if it fails midway (#16312)

* Fix migration script not being able to run if it fails midway

* Fix old migration script

* Fix old migration script

* Refactor CorruptionError

1 files changed, 12 insertions, 1 deletions

diff --git a/db/migrate/20210421121431_add_case_insensitive_btree_index_to_tags.rb b/db/migrate/20210421121431_add_case_insensitive_btree_index_to_tags.rb
index ed359e8cd..e492c9e86 100644
--- a/db/migrate/20210421121431_add_case_insensitive_btree_index_to_tags.rb
+++ b/db/migrate/20210421121431_add_case_insensitive_btree_index_to_tags.rb
@@ -1,8 +1,19 @@
+require Rails.root.join('lib', 'mastodon', 'migration_helpers')
+
 class AddCaseInsensitiveBtreeIndexToTags < ActiveRecord::Migration[5.2]
+  include Mastodon::MigrationHelpers
+
   disable_ddl_transaction!
 
   def up
-    safety_assured { execute 'CREATE UNIQUE INDEX CONCURRENTLY index_tags_on_name_lower_btree ON tags (lower(name) text_pattern_ops)' }
+    begin
+      safety_assured { execute 'CREATE UNIQUE INDEX CONCURRENTLY index_tags_on_name_lower_btree ON tags (lower(name) text_pattern_ops)' }
+    rescue ActiveRecord::StatementInvalid => e
+      remove_index :tags, name: 'index_tags_on_name_lower_btree'
+      raise CorruptionError if e.is_a?(ActiveRecord::RecordNotUnique)
+      raise e
+    end
+
     remove_index :tags, name: 'index_tags_on_name_lower'
   end