cue-lang/cue v0.9.0-alpha.2

on GitHub

This release includes the first experimental version of the new evaluator, as well as many other changes including the ongoing modules experiment. More details below.

As a reminder: users can register their projects with Unity, our regression and performance testing setup. Unity is used to ensure that a project's CUE evaluations do not unexpectedly stop working or regress in performance. Adding your project to Unity not only guarantees that we will not break your tests unexpectedly, but it also helps to improve the quality of each CUE release. Follow this link to learn more about Unity, install it, or get in touch with any questions.

Evaluator

The new evaluator can now be enabled via CUE_EXPERIMENT=evalv3. It is not yet complete, and some known bugs remain, but over 95% of the existing tests are passing and the performance already looks promising. Disjunctions and initial structure sharing are now implemented as well.

Work on this new evaluator will continue during the v0.9 release cycle. We will only turn on the new evaluator by default once we are reasonably confident that there are no significant regressions, which may happen in a future release cycle like v0.10. In the meantime, testing via CUE_EXPERIMENT=evalv3 and bug reports are welcome.

We have also published a more detailed update on the performance umbrella issue, which you can subscribe to for updates. You can also take a look at the Evaluator Roadmap project to see the planned work remaining.

CL 1186144 fixes a number of Environment.up panics involving calls to Value.Expr, which affected users of the Go API as well as the openapi encoding.

CL 1185458 ensures we detect permanent errors for undefined fields earlier, necessary for the permanent errors fix in tools/flow below.

Modules

cmd/cue now supports OAuth2 refresh tokens when interacting with $CUE_REGISTRY, so that the user doesn't have to re-run cue login once their access token expires.

CL 1191618 changes the modules client to treat "forbidden" errors as "not found" when finding which OCI repository contains a CUE module. This should resolve some unexpected "forbidden" failures when dealing with certain OCI registry services.

CL 1192905 adds initial support for the source field in cue.mod/module.cue files, which will soon be used as part of the proposal to determine what files go into a CUE module.

As a reminder, the ongoing and planned work can be seen in the Modules Roadmap, and we continue to hold regular Modules feedback sessions.

Encodings

The Encodings project was kicked off at the last CUE Community Update call. As part of this, we now have an #encodings channel on Slack, as well as an Encodings Roadmap project on GitHub where the ongoing and planned work can be seen.

In this release, the new YAML decoder is available in experimental form and enabled by default, given that all of our tests are already passing. You can disable it via CUE_EXPERIMENT=yamlv3decoder=0. The old YAML decoder will be removed in a future release once we're reasonably confident that no significant regressions are present.

Go API

CL 1187452 teaches tools/flow to fail when a task encounters a permanent error, which were being ignored before.

CL 1191227 adds a cue/token.File.Lines getter method, much like go/token.File.Lines was added in Go 1.21.

CL 1191226 teaches cue/literal.ParseNum to support both positive and negative signs for consistency.

CL 1193030 ensures that cue/load.Instances always returns instances in a deterministic order, in particular when multiple instances share the same directory.

CL 1185361 deprecates cue/load.Config.StdRoot, which has not worked as advertised for some time.

cmd/cue

CL 1189314 adds a cue fmt --check flag to list badly formatted files rather than modifying them directly.

CL 1192180 speeds up cue fmt by ensuring that it only processes each CUE file once, rather than formatting files from parent directories as well.