4.16.0

[4.16.0] - 2020-02-04

This release introduces new types for building user properties and representing arbitrary JSON values. In the next major version, these will entirely replace the current deprecated equivalents.

Added:

• NewUserBuilder, and its associated interfaces UserBuilder and UserBuilderCanMakeAttributePrivate. This is the new preferred mechanism for creating User instances when you need to set multiple properties; it reduces unsafe and inconvenient use of pointers.
• User property getter methods such as GetName().
• The SDK has a new dependency on gopkg.in/launchdarkly/go-sdk-common.v1, which provides the helper types ldvalue.Value and ldvalue.OptionalString.
• In LDClient, JSONVariation and JSONVariationDetail are the new preferred mechanism for evaluating flags whose values can be of any JSON type. The value is represented as an ldvalue.Value rather than a json.RawMessage, but can be easily converted to json.RawMessage or to other Go types.
• In LDClient, TrackData and TrackMetric are the new preferred versions of Track and TrackWithMetric; they use ldvalue.Value rather than interface{} for the data parameter.
• EvaluationReason methods GetRuleIndex(), GetRuleID(), GetPrerequisiteKey(), GetErrorKind(). These were formerly only on concrete implementation types such as EvaluationReasonRuleMatch; they are being added to the interface type because in a future version, it will be changed to a struct.

Fixed:

• By default, the SDK should log to os.Stderr with a minimum level of ldlog.Info, omitting only Debug-level messages. A bug introduced in 4.12.0 caused the default logger not to produce any output. It will now log at Info level by default again, as documented.

Deprecated:

• All exported fields of User. In a future version, these will be hidden. Use getters such as GetName() to read these fields, and NewUserBuilder to set them.
• In LDClient, JsonVariation, JsonVariationDetail, Track, and TrackWithMetric. Use JSONVariation, JSONVariationDetail, TrackData, TrackEvent, or TrackMetric instead.
• The EvaluationReason implementation types such as EvaluationReasonRuleMatch are deprecated. Instead of casting to these types, use EvaluationReason methods such as GetKind() and GetErrorKind().