Adds the POC Result section (POC on branch bast-validator-poc, commit
f371fe4 — 20/20 tests, full 416-test suite green, clippy/wasm/doc clean).
Hypothesis confirmed: a recursive walker over the BAST type tree fully
replaces the 19 custom keyword validators on the validate_bytes path,
recovers OQ-008 union variant dispatch, and fixes the enum-membership
dead constraint. The POC code is reference scaffolding on the branch
and is not merged to main — it is superseded by Phase 1 step 5.
Marks Phase 1 step 2 and the POC Scope section as done with pointers to
the result section.
Elevates the deferred AlkTypeError::Validation payload-shape question
to OQ-BAST-001: keep jsonschema::ValidationError<'static> (POC choice,
simplest, dependency stays) vs introduce Validation(String) (drops
jsonschema from the error type; semver-relevant public-API change).
Decision belongs to the production refactor.
Verification: doc-only change, no code touched.
- Rewrite Validator Split around BAST-native validator for
validate_bytes (walks BAST, checks value-domain constraints, no
external JSON Schema needed); validate_json uses standard
jsonschema::Validator from consumer-provided JSON Schema
- Add targeted POC: BAST-native validator replacing 19 custom keyword
validators on the bytes path, verified via existing test suite
- Fix meta-schema: require count on arrays (variable-element arrays
deferred per OQ-001), add optional fields array to UnionDef for
field-name discriminators
- Remove lying no-count array example, replace with deferred note
- Document dead enum constraint (materialized index never matches
string-membered enum); BAST-native validator fixes it via index
bounds check
- Resolve all 7 OQs + 3 spec gaps as D-BAST-001 through D-BAST-008
- Update Migration Path, Risks table, Engine internals to reflect
BAST-native validator
- Clarify 'no pocs needed' was an overcorrection: layout swap needs
no POC, but the validation model does
Verification: docs-only change, no code affected
- Remove the four proposed POCs: they were implementation smoke tests,
not de-risking probes. The pivot is a backend swap on a proven layout
engine; byte-identity is already proven and the layout code is
unchanged, so there is nothing empirical left to de-risk.
- Remove the recursive TreeNode example and the recursion mention in
design principle 2: recursion is not a binary-layout concern and the
engine has no cycle detection.
- Add a Spec Gaps section: validate_bytes semantics after keyword
validator removal (UnionValidator variant dispatch regression),
arrays of variable-length elements (engine rejects them), and
field-name discriminator unions (meta-schema cannot express them).
- Reframe the engine change as an accessor-layer refactor: the
walkers' (kind, field list, annotations) reads change; everything
beneath them carries over unchanged.
Correct the validator split section to clarify that jsonschema is
not removed — it remains the JSON Schema validator for both paths
(BAST meta-schema validation and standard JSON payload validation).
Only the custom keyword registration path is removed. Also fix the
build_validator and validate_json entries in the engine changes
table to reflect that they are repurposed, not removed.
Proposes replacing custom JSON Schema keywords with a standalone
kind-based JSON format (BAST) using / for composition.
Covers format design, meta-schema, engine changes, validator split,
codegen future, ABI adapter potential, migration path, 7 open
questions, and 4 proposed POCs.
glm-5.2
deepseek-v4-pro