Releasing version 3.0.0

Author: LaunchDarklyReleaseBot

CHANGELOG.md

@@ -2,6 +2,25 @@
 
 All notable changes to the project will be documented in this file. This project adheres to [Semantic Versioning](http://semver.org).
 
+## [3.0.0] - 2022-11-30
+This major version release of `go-sdk-common` corresponds to the upcoming v6.0.0 release of the LaunchDarkly Go SDK (`go-server-sdk`), and cannot be used with earlier SDK versions.
+
+### Added:
+- The new package `ldcontext` with the types `Context` and `Kind` defines the new "context" model. "Contexts" are a replacement for the earlier concept of "users"; they can be populated with attributes in more or less the same way as before, but they also support new behaviors. More information about these features will be included in the release notes for the v6.0.0 SDK release.
+- The new package `ldattr` defines the attribute reference syntax, for referencing subproperties of JSON objects in flag evaluations or private attribute configuration. Applications normally will not need to reference this package.
+
+### Changed:
+- The minimum Go version is now 1.18.
+- The SDK packages now use regular Go module import paths rather than `gopkg.in` paths: `gopkg.in/launchdarkly/go-sdk-common.v2` is replaced by `github.com/launchdarkly/go-sdk-common/v3`.
+- The type `lduser.User` has been redefined to be an alias for `ldcontext.Context`. This means that existing application code referencing `lduser.User` can still work as long as it is treating the user as an opaque value, and not calling methods on it that were specific to that type.
+- `lduser.NewUser` and `lduser.UserBuilder` now create an instance of `Context` instead of `User`. This is as a convenience so that any code that was previously using these methods to construct a user, but did _not_ reference the `User` type directly for the result, may still be usable without changes. It is still preferable to use the new constructors and builders for `Context`.
+- The `Secondary` attribute which existed in `User` does not exist in `Context` and is no longer a supported feature.
+- It was previously allowable to set a user key to an empty string. In the new context model, the key is not allowed to be empty. Trying to use an empty key will cause evaluations to fail and return the default value.
+- If you were using JSON serialization to produce a representation of a `User`, the new type `Context` uses a different JSON schema, so any code that reads the JSON will need to be adjusted. If you are passing the JSON to other code that uses LaunchDarkly SDKs, make sure you have updated all SDKs to versions that use the new context model. (However, _unmarshaling_ a `Context` from JSON data will still work correctly even if the JSON is in the old user format.)
+
+### Removed:
+- Removed the `Secondary` meta-attribute in `lduser.UserBuilder`.
+
 ## [2.5.1] - 2022-06-30
 ### Changed:
 - If you create an `ldvalue.Value` with the `ldvalue.Raw(json.RawMessage)` constructor, and you pass a zero-length or nil value to the constructor, and then encode the `Value` to JSON with `json.Marshal` or an equivalent method, the JSON output will now be `null` (that is, the literal characters `null` representing a JSON null value). Previously it would have been a zero-length string, which is not valid as the JSON encoding of any value and could cause the SDK to output a malformed JSON document if the document contained such a value.