The gap-only manifest stopped guarding a case once it was fixed, so later
work silently regressed previously-fixed cases (caught only by an external
full-suite run, not the gated sweep or full corpus). Replace it with a full
manifest of all 402 official cases (Tests/Fixtures/yaml-test-suite-manifest.yaml),
each carrying its conformant expectation and a passing/gap status, with every
case's files vendored. The gated sweep now asserts every passing case still
passes (the regression guard) and every gap still reproduces, so any regression
fails the build.
The honest gate-enforced count is 329/402 passing (the earlier 348 came from a
more lenient one-time oracle).
Repairs three regressions the new gate revealed: the bucket-6 tab rule
over-rejected tabs in block-scalar content and as separation before a scalar
value (root cause: the batch scanner and the incremental TokenCursor had
divergent line-start loops; unified onto a single scanStep, fixing 96NN/00,
96NN/01, R4YG, Y79Y/001, DK95/00, DK95/03, DK95/07, 6CA3, Q5MG, J3BT); an anchor
on a prior line before an alias key wrongly rejected 26DV; and a tag-only flow
key mis-parsed WZ62. Genuine tab-indentation errors (4EJS, Y79Y/000) still reject.
Vendor the 206 official YAML test suite cases (yaml/yaml-test-suite, data branch, commit 6ad3d2c) that PureYAML does not yet handle correctly, under Tests/Fixtures/yaml-test-suite/, with a manifest recording each gap's category and current behavior.
Add an opt-in conformance sweep (scripts/check-yaml-test-suite.sh, gated behind PUREYAML_RUN_YAML_TEST_SUITE=1) that reproduces every recorded gap, so a future fix must update the manifest. Document the measured result (196/402 passing) and the ordered plan for closing the gaps in docs/YAML_TEST_SUITE_CONFORMANCE.md.
No parser behavior changed.
Add structured validation diagnostics, JSON and Yams comparison gates, and lazy token/event parsing so production behavior is measured without retaining full intermediate parser arrays.
