This release fixes dozens of bugs in the old and new evaluators and includes more JSON Shema improvements.

Changes which may break some users are marked below with: ⚠️

Evaluator

Over a dozen closedness and cycle detection bugs have been fixed in CUE_EXPERIMENT=evalv3, including a few which caused panics or endless evaluation.

CL 1202685 tweaks cuecontext.New to follow CUE_EVALUATOR=evalv3 when the cuecontext.EvaluatorVersion option is not used.

CL 1202903 fixes embed.New so that it works without needing to set CUE_EXPERIMENT=embed as well.

CLs 1202120 and 1202211 fix a number of issues where validators like matchN or struct.MinFields would give incorrect results.

Go API

⚠️ CL 1202244 tweaks the cue.Value API to consider open lists as concrete, aligning with the spec.

⚠️ CLs 1202285 and 1202286 remove the cue.Value.Subsumes and cue.Value.Split methods, which have been deprecated and hidden for years.

Encodings

JSON Schema spec compatibility is improved further by fixing a number of bugs and adding missing features.

Builtins

CL 1202104 adds the net.URL and net.AbsURL validators, needed by JSON Schema.

This release includes fixes for two bugs which were uncovered and resolved in the last few weeks.

cmd/cue

CL 1202646 fixes a panic for users of the cmd/cue/cmd Go API.

CL 1202738 fixes a bug when using @if attributes in files specified directly as command line arguments.

This release adds a new cycle algorithm to the new evaluator, removes some long-deprecated Go APIs, and includes multiple improvements to the existing encodings.

Evaluator

CL 1201897 lands a new cycle algorithm in CUE_EXPERIMENT=evalv3, which is much simpler than the old algorithm and is needed to unlock further bug fixes and performance improvements.

Go API

CLs 1201768, 1201933, 1201934, 1201936, and 120193 remove encoding/openapi Go APIs which have been deprecated for some time and already have reasonable alternatives available.

CL 1201962 removes fields from cue/build.Instance and cue/load.Config which have been deprecated and unused for some time.

CL 1201963 removes APIs from encoding/json and encoding/yaml which have been deprecated for some time and already have reasonable alternatives available.

Encodings

CL 1201910 allows configuring how encoding/jsonschema maps URLs to values within a package.

CL 1201935 refactors encoding/openapi so that it can directly use the existing CUE value encoder for JSON, rather than a parallel encoder of CUE syntax trees to JSON which had to be maintained separately.

CLs 1201807, 1201808, 1201824, and 1201826 improve the performance of encoding CUE values to JSON, resulting in as much as a 10x improvement in wall time and memory usage for deeply nested CUE values.

This release includes a new matchIf built-in validator, many more improvements to JSON Schema and TOML support, as well as some fixes.

Evaluator

CL 1200942 adds a new matchIf builtin, similar to matchN, which makes it significantly easier to implement the if, then, and else keywords in JSON Schema.

Modules

CL 1201493 gives a better error message when a module is not found.

CL 1201522 fixes a bug where imports did not work properly when using cue/load.Config.Package = "*".

Encodings

A significant amount of work has gone into improving JSON Schema support, fixing many bugs and producing better CUE output, as well as leveraging the new matchN and matchIf builtins. While this work is still in progress, we already expect an overall improvement compared to v0.10.0. This work will also form the basis for CUE modules for well-known services that will be published to the Central Registry.

CL 1200901 improves filetype tags, as described by cue help inputs, so that unknown tag=value pairs cause failures, and invalid pair combinations aren't silently ignored.

CLs 1200899 and 1200924 split JSON Schema's strictness option into StrictFeatures and StrictKeywords which allows erroring when unimplemented features are used, but not when unknown keywords are used. --strict is also superseded by jsonschema+strict:.

CL 1200932 turns on JSON Schema's new StrictFeatures option on by default, a saner default as we know which features we have not yet implemented and so the schema cannot be interpreted correctly.

CL 1201111 teaches default filetype tags to be applied in the default auto interpretation mode as well.

CL 1201113 adds the StrictFeatures and StrictKeywords options to OpenAPI, mirroring the options added to JSON Schema.

CL 1200888 adds support for decoding TOML dates and times.

Builtins

CL 1201474 adds a new encoding/toml package with Marshal and Unmarshal APIs, following the addition of TOML support in v0.10.0.

CL 1201115 removes strconv.ParseComplex, which never worked in any past CUE release and does not seem like an useful API to have in its current form.

cmd/cue

CL 1201709 fixes a minor regression introduced in CUE v0.9.0 where cue help cmd mycmd ./mypkg stopped showing a valid command's help text.

This release includes a new matchN built-in validator, many fixes for the new evaluator, and a significant amount of work on JSON Schema.

Evaluator

A number of crashes, regressions, and other bugs have been fixed in the new evaluator, which can be enabled by CUE_EXPERIMENT=evalv3. For more details, see our latest performance update. Thanks to all who have tested the new evaluator and reported bugs!

CL 1198922 adds a new matchN built-in validator, necessary implement a host of validators such as the JSON Schema equivalents of not, oneOf, and anyOf. See the new how-to guide for it.

CL 1199898 relaxes the evaluator to allow referencing required fields via selectors, rather than failing like we do with optional fields. This should help with the transition of CUE schemas from regular to required fields, such as those decoded from JSON Schema.

CL 1200221 removes support for arithmetic operators on lists, and CL 1200221 teaches cue fix to rewrite most of them. We have added a doc page with more details and examples.

CL 1199684 teaches the evaluator to allow non-concrete values to be passed as parameters to certain builtin functions such as yaml.Validate.

CL 1199723 deduplicates errors when pairwise-combining them, as the duplication could result in large memory usage.

Modules

CL 1199541 wraps up the CUE modules experiment by dropping support for CUE_EXPERIMENT=modules=0, now that the new mode has been the default since CUE v0.9.0, and we are not aware of any remaining regressions.

Go API

CL 1200507 deprecates astutil.Cursor.Import, which is now superseded by astutil.Sanitize.

Encodings

A significant amount of work has gone into improving JSON Schema support, fixing many bugs and producing better CUE output, as well as leveraging the new matchN builtin. While this work is still in progress, we already expect an overall improvement compared to v0.10.0. This work will also form the basis for CUE modules for well-known services that will be published to the Central Registry.

CL 1199938 teaches the TOML decoder to produce CUE nodes with positions, allowing errors to include positions within TOML files.

CL 1199541 wraps up the new YAML decoder experiment by dropping support for CUE_EXPERIMENT=yamlv3decoder=0, allowing the 8400 lines of code in internal/third_party/yaml to be removed.

Builtins

CL 1194425 tweaks the yaml.Validate and json.Validate functions to allow non-concrete CUE values as schema parameters.

CL 1199602 adds a list.MatchN function, surfacing the matchN built-in validator for use in the JSON Schema decoder.

CL 1199881 tweaks uuid.Valid so that it is consistent with uuid.Parse in terms of what UUID formats are accepted.

cmd/cue

CL 1199634 drops support for the deprecated short form of cue cmd; users of cue foo should now call cue cmd foo.

CL 1200351 fixes a bug in cue fix where it would not operate on directories with multiple packages.

CL 1200498 fixes a bug in cue fix where added imports would end up with mangled names.

CL 1200554 teaches cue fix to work on standard input and output, like other sub-commands.

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.

This release candidate includes fixes to the evaluator and various encodings.

Evaluator

CLs 1198736 and 1198860 fix two panics uncovered in the new evaluator, enabled via CUE_EXPERIMENT=evalv3.

Encodings

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 1198831 teaches the JSON Schema encoding to decode required properties as CUE required fields.

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 1199025 teaches the TOML decoder to include positions in error values.

CL 1198819 fixes the decoding of TOML keys with underscore prefixes.

This release includes fixes to the evaluator and APIs as well as initial support for the TOML encoding.

Evaluator

CL 1198356 fixes a panic in the new evaluator relating to the new mechanism for tracking closedness information.

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.

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.

Builtins

CL 1198636 tweaks the existing path.Match and tool/file.Glob builtins 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 *.

Go API

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 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.

This release includes many fixes and enhancements, particularly for modules. It also starts requiring Go 1.22 or later, as Go 1.23.0 will be released very soon.

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.

Go API

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

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

Evaluator

CLs 1195897 and 1196094 fix two crashes with CUE_EXPERIMENT=evalv3 as reported by users.

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

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 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.

Encodings

CL 1195628 ensures that cue/format prints a newline after every comment.

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 where a comment at the start of a CUE file would sometimes be indented.

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

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

CL 1196332 tweaks the JSONL (newline-delimited JSON) so that line numbers aren't reset with each new JSON value.

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

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.

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.