Changes to Package Header

Hydra 1.0 introduced the package header and required everyone to specify it in their configs. This was done to facilitate a transition from a model where the packages are global to a model where - by default - package are derived from the config group.

e.g: Change of the default package for server/db/mysql.yaml from _global_ to server.db.

Hydra 1.1 completes this transition.

• If a package header is not specified, the config will have the default package as described above.
• _group_ and _name_ in package header are deprecated (You can still use a literal package header).

info

Another important change in Hydra 1.1 is the Changes to default composition order.

Migration

If your header is # @package _group_, remove the header.

db/mysql.yaml in Hydra 1.0

# @package _group_
host: localhost

db/mysql.yaml in Hydra 1.1

host: localhost

If your header is using _group_ or _name_ to specify a package other than the default package, Specify the literal package:

db/mysql.yaml in Hydra 1.0

# @package _group_._name_
host: localhost

db/mysql.yaml in Hydra 1.1

# @package db.mysql
host: localhost

Compatibility with both Hydra 1.0 and 1.1

If your configs should be compatible with both Hydra 1.0 and Hydra 1.1, use literal package headers.

db/mysql.yaml in Hydra 1.0

# @package _group_
host: localhost

db/mysql.yaml in Hydra 1.1

# @package db
host: localhost