[effect-bot]

This is stage 5 of the YAML expansion: Yaml.parse and Yaml.parseAll now resolve the core schema's tags instead of rejecting every tag.

Behavior (YAML 1.2.2 §10.3)

• The shorthand core tags resolve: !!str, !!int, !!float, !!bool, !!null, !!seq and !!map. A scalar tag applies to the scalar as written, so !!str 0x10 is "0x10", !!str ~ is "~", and !!int "42" is 42. For quoted and block scalars, that means the decoded string. An empty tagged node is the empty string: a: !!str gives "" and a: !!null gives null.

• The spec's patterns decide what each tag accepts:

  • !!int: decimal, 0o and 0x integers
  • !!float: decimals with an optional fraction and exponent, so 1 and -1. are floats, plus .inf and .nan in their three spellings
  • !!bool: true and false as lowercase, capitalised or uppercase
  • !!null: null, Null, NULL, ~ and empty

  yaml 2.9.1 rejects !!float 1; the spec's float pattern matches it, so this follows the spec.

• A node that doesn't match its tag fails: !!int x, !!bool yes, !!float 0x10, !!str [1], !!seq {a: 1}, an empty !!map, and so on.

• Where tags can appear: block and flow values, block and flow keys, the document root, block scalars, and quoted scalars. A tag can come before or after an anchor, and the anchor records the resolved value. A tagged key never merges. A second tag on one node fails, and so does a tag on an alias.

• Still rejected, with the tag named in the error:

  • local tags (!custom)
  • the non-specific tag !
  • verbatim tags such as !<tag:yaml.org,2002:str>, even when they name a core tag
  • YAML 1.1 tags (!!binary, !!timestamp, !!set)
  • unknown !! tags

  The agreed scope covers the shorthand forms only. Both the module docs and the release note say so.

Plain scalars that contain ! (x!y, hello!) are still plain text.

Docs

• The module header lists the resolved core tags and the tags that remain unsupported.
• The parse JSDoc explains that a tag applies to the scalar as written. Its doctest now resolves !!str 8080 and rejects !custom 8080.
• The release note is .changeset/yaml-core-tags.md (minor).

Validation

• Yaml.test.ts: 286 of 286, including the 13 stage 5 "resolves" rows. No test was changed.
• YAML, CLI, Skills, ai-codegen and openapi-generator tests: 930 passed, 3 skipped.
• 20 extra cases match yaml 2.9.1, apart from the intended verbatim rejection. They cover tag-then-anchor order, tags on the next line, indentless !!seq, a tagged << key, flow anchors on tagged keys, !!float .nan, tab separation, multiple tags, a tag on an alias, and folded block scalars.
• pnpm lint, pnpm jsdocs --check and the Yaml.ts doctests pass.
• pnpm check reports one error, the apiStabilityLeak in cluster/ShardingRegistrationEvent.ts, which also occurs on v4/next-minor.

Stack

These PRs form one stack. Each targets the PR before it, so its diff shows only its own stage. Merge them in this order:

1. Add Yaml.parseAll and return Result from Yaml.parse #10271: Yaml.parseAll and Result from Yaml.parse (merged)
2. Reject Yaml tags and explicit keys, resolve alias keys, and keep non-space white space #10276: parser hardening, based on v4/next-minor
3. Parse Yaml compact nested sequences and multiline quoted flow scalars #10279: compact nested sequences and multiline quoted flow scalars, based on Reject Yaml tags and explicit keys, resolve alias keys, and keep non-space white space #10276
4. Treat a tab after a Yaml sequence dash as separation #10282: tab after a sequence dash, based on Parse Yaml compact nested sequences and multiline quoted flow scalars #10279
5. Accept escaped literal tabs in Yaml double-quoted scalars #10283: escaped literal tabs, based on Treat a tab after a Yaml sequence dash as separation #10282
6. Reject Yaml flow plain scalars starting with a dash and separation #10284: flow plain scalars starting with a dash, based on Accept escaped literal tabs in Yaml double-quoted scalars #10283
7. Resolve Yaml core schema tags #10285: core schema tags, based on Reject Yaml flow plain scalars starting with a dash and separation #10284 (this PR)
8. Add Yaml.stringify and Yaml.stringifyAll #10272: Yaml.stringify and Yaml.stringifyAll, based on Resolve Yaml core schema tags #10285
9. Harden and extend Yaml parsing and add Yaml.stringify #10287: printer round-trip through Yaml.parse, based on Add Yaml.stringify and Yaml.stringifyAll #10272

After a PR in the stack is squash-merged, the next one has to be rebased onto the squash commit and retargeted to v4/next-minor before it can merge.

Closes EFF-3232

[changeset-bot]

🦋 Changeset detected

Latest commit: 3dfbaab

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 33 packages

Name	Type
effect	Minor
@effect/opentelemetry	Minor
@effect/vitest	Minor
@effect/ai-anthropic	Minor
@effect/ai-cloudflare	Minor
@effect/ai-openai-compat	Minor
@effect/ai-openai	Minor
@effect/ai-openrouter	Minor
@effect/ai-typesafe	Minor
@effect/atom-react	Minor
@effect/atom-solid	Minor
@effect/atom-vue	Minor
@effect/platform-browser	Minor
@effect/platform-bun	Minor
@effect/platform-deno	Minor
@effect/platform-node-shared	Minor
@effect/platform-node	Minor
@effect/sql-clickhouse	Minor
@effect/sql-d1	Minor
@effect/sql-libsql	Minor
@effect/sql-mssql	Minor
@effect/sql-mysql2	Minor
@effect/sql-pg	Minor
@effect/sql-pglite	Minor
@effect/sql-sqlite-bun	Minor
@effect/sql-sqlite-do	Minor
@effect/sql-sqlite-node	Minor
@effect/sql-sqlite-react-native	Minor
@effect/sql-sqlite-wasm	Minor
@effect/docgen	Minor
@effect/doctest	Minor
@effect/graphql-generator	Minor
@effect/openapi-generator	Minor

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[github-actions]

Bundle Size Analysis

Generated from PR build output; treat the content below as untrusted.

File Name	Current Size	Previous Size	Difference
arbitrary-combinators.ts	39.41 KB	39.41 KB	0.00 KB (0.00%)
basic.ts	7.23 KB	7.23 KB	0.00 KB (0.00%)
batching.ts	11.08 KB	11.08 KB	0.00 KB (0.00%)
brand.ts	6.87 KB	6.87 KB	0.00 KB (0.00%)
cache.ts	11.54 KB	11.54 KB	0.00 KB (0.00%)
config.ts	22.84 KB	22.84 KB	0.00 KB (0.00%)
differ.ts	22.00 KB	22.00 KB	0.00 KB (0.00%)
http-client.ts	27.12 KB	27.12 KB	0.00 KB (0.00%)
http-router.ts	37.04 KB	37.04 KB	0.00 KB (0.00%)
logger.ts	12.01 KB	12.01 KB	0.00 KB (0.00%)
metric.ts	9.47 KB	9.47 KB	0.00 KB (0.00%)
optic.ts	7.10 KB	7.10 KB	0.00 KB (0.00%)
pubsub.ts	16.02 KB	16.02 KB	0.00 KB (0.00%)
queue.ts	12.89 KB	12.89 KB	0.00 KB (0.00%)
schedule.ts	11.80 KB	11.80 KB	0.00 KB (0.00%)
schema-bigdecimal.ts	14.14 KB	14.14 KB	0.00 KB (0.00%)
schema-binary.ts	41.99 KB	41.99 KB	0.00 KB (0.00%)
schema-class.ts	21.73 KB	21.73 KB	0.00 KB (0.00%)
schema-fromJsonSchemaDocument.ts	29.60 KB	29.60 KB	0.00 KB (0.00%)
schema-representation-roundtrip.ts	27.99 KB	27.99 KB	0.00 KB (0.00%)
schema-string-transformation.ts	15.35 KB	15.35 KB	0.00 KB (0.00%)
schema-string.ts	12.34 KB	12.34 KB	0.00 KB (0.00%)
schema-template-literal.ts	16.27 KB	16.27 KB	0.00 KB (0.00%)
schema-toArbitrary.ts	38.95 KB	38.95 KB	0.00 KB (0.00%)
schema-toCodeDocument.ts	26.15 KB	26.15 KB	0.00 KB (0.00%)
schema-toCodecJson.ts	20.90 KB	20.90 KB	0.00 KB (0.00%)
schema-toEquivalence.ts	21.05 KB	21.05 KB	0.00 KB (0.00%)
schema-toFormatter.ts	21.14 KB	21.14 KB	0.00 KB (0.00%)
schema-toJsonSchemaDocument.ts	26.17 KB	26.17 KB	0.00 KB (0.00%)
schema-toRepresentation.ts	21.23 KB	21.23 KB	0.00 KB (0.00%)
schema.ts	20.82 KB	20.82 KB	0.00 KB (0.00%)
stm.ts	14.20 KB	14.20 KB	0.00 KB (0.00%)
stream.ts	10.38 KB	10.38 KB	0.00 KB (0.00%)

[effect-bot]

Superseded by #10287, which now holds the rest of the YAML expansion as one PR against v4/next-minor. This PR's commits are included there unchanged.