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.
Implement libyaml's simple-key mechanism for flow context: the scanner records a potential key position before a plain or quoted scalar, an anchor/tag, or a [/{ opener, and a later ':' splices a mappingKey token retroactively in front of that node. This lets a quoted scalar ("k":v), a nested collection ({k}:v), or a property-carrying node (&c c: d) become a flow mapping key. In flow context ':' is always a value indicator and '?' always an explicit-key indicator regardless of the next character (the block-only following-blank lookahead is disabled), so adjacent forms and trailing '?' parse, and multi-line plain keys fold before the ':' is read. The flow parser is rebuilt around the flow_sequence_entry / flow_mapping_key / flow_mapping_value productions, composing empty scalars for absent keys and values. The streaming token cursor now buffers an open flow collection's tokens until it closes so the retroactive key splice stays valid.
Flips 10 official YAML test suite cases (348/402): 4FJ6, 8KB6, 9BXH, 9MMW, CN3R, DFF7, FRK4, NJ66, UT92, CT4Q. Flow collections used as block mapping keys (LX3P, 6BFJ) need the splice in block context and stay tracked. Updates manifest, fixtures, counts, and roadmap.
A mapping key is a full node: it may carry &anchor and !tag properties and may itself be an *alias. Fixes: (1) anchor/alias name scanning now stops at the first non-name character per yaml_parser_scan_anchor, so *a: reads as alias 'a' plus a mapping indicator instead of name 'a:'; (2) the block-mapping parser enters on a leading node property or alias, attaches same-line key properties to the key node, and emits alias keys directly; (3) an anchor or tag at value position with no same-line node composes an empty (null) value carrying the property, so 'a: &anchor' registers the anchor; (4) the composer registers an anchor's resolved model value (an empty anchored scalar registers null); (5) implicit keys with trailing spaces before the colon are recognized.
Flips 10 official YAML test suite cases to passing (280/402), including G9HC now correctly rejected. 2SXE no longer false-rejects but still value-mismatches on compact-mapping interpretation (a separate gap), so it is reclassified in the manifest rather than removed. Updates the manifest, fixtures, counts, and roadmap.
Compose an empty scalar wherever a node is grammatically required but the next token is a structural indicator or line/stream end, mirroring libyaml's process_empty_scalar: after a tag or anchor property with no node, as an absent mapping value (block and flow), as an absent mapping key (both the plain ': v' form and the explicit '?' form), in flow empty key/value forms ({ : }, { , : v }), and for an indented block node following properties. Also fixes a pre-existing block-sequence bug that nested a sibling '-' as a child when only properties remained on the entry line.
Empty scalars resolve through the existing resolver against the empty string, so !!str yields the empty string, bare empty or !!null yields null, and an empty key yields the empty string.
Flips 20 official YAML test suite cases to passing (270/402). CT4Q no longer false-rejects but still value-mismatches on flow plain-scalar folding (a separate gap), so it is reclassified in the manifest rather than removed. Updates the gap manifest, fixtures, counts, and roadmap.
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.
