Outdated Declarations

Heksher-py is prepared for your setting declarations to be outdated and overridden by a newer declaration, and strives to be as backwards-compatible with newer declarations.

Default Value Changed

If a default value for the server is different from the local declaration, the server’s default is used (so long as it is compatible with the setting’s type, see Rejecting Values).

Coercing Values

Sometimes, the types of settings are upgraded in the server. This can lead to a situation where a rule value, or the setting’s default value is incompatible with the local declaration’s type. In this case, heksher-py may attempt to convert the value to the local declaration’s type. These coercions, when they are possible, will almost always be with some data loss. For more information about the various coercions, see SettingType.Coercions.

If a coercion occurs, it will be logged.

Refusing coercions

For some settings, we may want to avoid coercion. For example, if a setting is a mapping, then coercion will simply discard any incompatible key-value pairs, and the setting might require that all the keys be present. In this case, we can set a setting’s Setting’s on_coerce parameter to reject or even customize the behaviour of coercions.

Rejecting Values

Sometimes coercion is not possible, and we want to reject the value. For example, if we declare a setting as a list, but that declaration has already be overridden to be a string, then no coercion will be possible. In this case, we simply discard the rule with the incompatible value, or disregard the default value. In either case, a message will be logged.

Note

On ignoring server defaults

If server’s default value is ignored, then the setting’s default value will first fall back not to the setting’s local default value, but to the last valid server default value, if any exist.

Rejecting Rules

Sometimes, a setting’s configurable features change to subsets that the local declaration does not support. If any rule relies on context features that are not in the local setting declaration’s configurable features, then the rule will be discarded with a log message.