raise a better exception for renaming long indexes

1 files changed, 3 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
index 51853c6812..b4b066c06e 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb
@@ -478,6 +478,9 @@ module ActiveRecord
         end
 
         def rename_index(table_name, old_name, new_name)
+          if new_name.length > allowed_index_name_length
+            raise ArgumentError, "Index name '#{new_name}' on table '#{table_name}' is too long; the limit is #{allowed_index_name_length} characters"
+          end
           execute "ALTER INDEX #{quote_column_name(old_name)} RENAME TO #{quote_table_name(new_name)}"
         end