Deprecated behaviour¶
Specifying AllowNone and Default¶
In Config Suite 0.6 the schema keywords AllowNone and Default was introduced. AllowNone is used to indicate whether a basic element can take the value None and is defaulted to False. And Default can be used to provide default values for elements and it defaults to None. It should be noted that there is a strong correlation between Default, AllowNone and Required. In particular, the later can be deduced from the first two. In short, if an element is required it should neither allow None values nor have a default. Because if so, it would not be required.
Here is a complete table of valid combinations of the three options:
| AllowNone | Default | Required |
|---|---|---|
| True | True | False |
| True | False | False |
| False | True | False |
| False | False | True |
Required is deprecated¶
In the transition to Config Suite 0.6 specifying elements in the schema as Required is deprecated. In particular, it is superseded as described above by specifying AllowNone and Default. The plan is that 0.6 will still function with Required in the schemas to ease the process of introducing AllowNone and Default. However, upon initialization ConfigSuite now accepts an optional, boolean argument named deduce_required. If deduce_required is set to False (which is the default value) a deprecation warning will be raised. After the transition to using AllowNone and Default has been made (which the reader is heavily encouraged to finish before considering the deprecation of Required) the consumer is expected to toggle deduce_required to True. At this point a new deprecation warning will be raised upon creation of a ConfigSuite instance if the schema contains a Required specification. However, they are now all safe to remove and you are indeed encouraged to do so.
Then in the 0.7 release deduce_required will default to None. If True is passed instead we will raise a deprecation warning and for any other value we will raise an exception. The idea is that in 0.7 you can safely stop setting deduce_required and then be ready for 0.8, where deduce_required will not be recognized as an optional argument anymore.