This release includes experimental support for the embed proposal, many fixes for the new evaluator and modules, as well as many other fixes and enhancements.

Evaluator

CLs 1195897, 1196094, 1198356, 1198736, and 1198860 fix crashes with CUE_EXPERIMENT=evalv3 as reported by users.

CLs 1199272, 1199273, and 1199340 fix spurious "field not allowed" error regressions in the new evaluator.

CL 1198566 fixes a performance regression introduced in CUE v0.6 where cue cmd and tools/flow became many times slower on some inputs.

CL 1198350 ensures that all interpreter errors, such as those from @embed attributes, include position information.

Embed proposal

With CUE_EXPERIMENT=embed, CUE now supports the embedding of non-CUE files within a CUE package. See the embed proposal and its design document for details, as well as the new how-to guide for the feature.

Modules

The cue help documentation for modules and inputs has been expanded, and a number of error messages when using or publishing modules are now more helpful.

A new concept guide on CUE language versions documents the language.version field in cue.mod/module.cue files.

CL 1198249 adds support for an @ignore file attribute to unconditionally ignore a file when loading packages or calculating dependencies.

CL 1198003 teaches the CUE loader to support symbolic links when loading from local directories, matching the behavior before CUE_EXPERIMENT=modules was introduced.

CL 1198143 tweaks cue mod init without an argument to create a module with the module path cue.example rather than an empty path that made the module file invalid.

CL 1197530 fixes the behavior of build tags, and also adds support for parentheses in build tag expressions.

CL 1197531 implements better caching when evaluating dependencies, which should speed up evaluation of modules that use multi-directory packages.

Go API

CL 1196721 disallows importing or loading packages with an underscore qualifier like foo.com/bar:_, as it was never intended behavior. Users should use the new embed proposal instead.

CL 1198555 adds a cue/load.Config.SkipImports option to avoid loading instances from import statements. This particularly helps cue fmt, where the loading caused unwanted slowness and unnecessary errors.

CL 1196820 adds a cue.LanguageVersion function to obtain the current version of the language spec that the Go module implements.

CL 1197160 implements considered support for build tags in modules. Build tags are considered false when outside the main module.

CL 1198686 fixes cue/load so that it no longer produces extra invalid packages when Config.Package was set to * and nested packages were loaded.

CL 1198351 fixes a bug in astutil.Sanitize where unused imports were not being fully removed from ast.File, causing errors in cue trim where all uses of an import were removed.

CL 1198494 speeds up the Path method on wrapped errors, which causes noticeable speed-ups in some edge cases.

CL 1198157 fixes cue/parser to accept keywords as valid selectors, aligning with the language specification.

Encodings

Initial support for TOML is included in this release, including support in cmd/cue and an experimental Go package. See the issue tracker for remaining work in this space.

CLs 1199309, 1199139, 1199306, 1199214, 1199398, 1199308, and 1199309 resolve a number of issues when decoding JSON Schema files.

CLs 1196332, 1199094, and 1199103 fix the JSON decoder to provide correct position information when decoding JSONL files or encountering a syntax error.

CL 1198874 fixes the loading of JSON files to reject multiple newline-delimited values, as those ar only allowed in NDJSON or JSONL files.

CL 1198876 teaches the YAML decoder to decode empty documents as null, aligning with the YAML spec and fixing panics when loading empty YAML files.

CL 1196291 tweaks the YAML decoder so that comments following a field are attached to the entire field.

CL 1196436 tweaks the textproto decoder to correctly handle required and optional fields.

CLs 1195628 and 1199054 ensure that cue/format prints the correct white space before and after comments.

CL 1195884 teaches cue/format to preserve comments associated with ... ellipsis expressions.

CL 538624 fixes a bug where cue/format would start a CUE file with white space if it began with a clause.

CL 1196134 fixes a bug in cue/format where a comment at the start of a CUE file would sometimes be indented.

CL 1196135 fixes a bug in cue/format where index or selector expressions could cause extra tab indentation.

Builtins

CL 1196212 adds a list.Reverse function to reverse the elements of a list.

CL 1197452 tweaks tool/exec.Run so that its errors are unambiguous when any command arguments contain white space.

CL 1198636 tweaks path.Match and tool/file.Glob to reject ** wildcard patterns as unsupported, to avoid confusion and allow future changes to their behavior. Note that this change may break uses of ** patterns, which behaved like *.

cmd/cue

CL 1196822 adds a --language-version flag for cue mod init and cue mod edit to set the language.version value.

CL 1197185 teaches cue mod resolve to work on the current module when no arguments are given.

CL 1196370 teaches cue mod registry to gracefully shut down when interrupted.