Support default values in new version of `rename_column_concurrently` migration helper
Summary
The original version of our rename_column_concurrently
helper had a bug with no-downtime deployments: #297378 (closed)
We fixed this with a reimplementation of the helper in !52032 (merged), which was added to the new Gitlab::Database::MigrationHelpers::V2
module, but this new version doesn't support default values yet and aborts with an error when trying to rename a column with a default value.
Improvements
Add support for default values.
As mentioned in !52032 (merged) this is non-trivial, but maybe we could at least implement support for defaults with constant values, and still abort with an error if we detect a default with an expression.
Involved components
lib/gitlab/database/migration_helpers/v2.rb