raise a better exception for renaming long indexes

3 files changed, 20 insertions, 0 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 7cc5e666af..99fa9b7d29 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract/schema_statements.rb
@@ -571,6 +571,9 @@ module ActiveRecord
       #   rename_index :people, 'index_people_on_last_name', 'index_users_on_last_name'
       #
       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
         # this is a naive implementation; some DBs may support this more efficiently (Postgres, for instance)
         old_index_def = indexes(table_name).detect { |i| i.name == old_name }
         return unless old_index_def
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
 
diff --git a/activerecord/test/cases/migration/index_test.rb b/activerecord/test/cases/migration/index_test.rb
index ac932378fd..b23b9a679f 100644
--- a/activerecord/test/cases/migration/index_test.rb
+++ b/activerecord/test/cases/migration/index_test.rb
@@ -36,6 +36,20 @@ module ActiveRecord
         assert connection.index_name_exists?(table_name, 'new_idx', true)
       end
 
+      def test_rename_index_too_long
+        too_long_index_name = good_index_name + 'x'
+        # keep the names short to make Oracle and similar behave
+        connection.add_index(table_name, [:foo], :name => 'old_idx')
+        e = assert_raises(ArgumentError) {
+          connection.rename_index(table_name, 'old_idx', too_long_index_name)
+        }
+        assert_match(/too long; the limit is #{connection.allowed_index_name_length} characters/, e.message)
+
+        # if the adapter doesn't support the indexes call, pick defaults that let the test pass
+        assert connection.index_name_exists?(table_name, 'old_idx', false)
+      end
+
+
       def test_double_add_index
         connection.add_index(table_name, [:foo], :name => 'some_idx')
         assert_raises(ArgumentError) {