The value-property indentation check used only the first property's mark,
so it caught a sole under-indented property ('seq:' then '&anchor') but not
a second one after an inline first ('key: &x' then a '!!tag' in column 1),
which still parsed.
The last consumed property is cursor.previous after consumeProperties, so
the check now uses it instead of the first mark, catching an under-indented
property whether it is the only one or a later one. Inline properties, a
property indented under the key, and a properly indented anchor-and-tag pair
are unaffected.
Measured against the official YAML test-suite, parse-level conformance
rises from 277/333 (83.2%) to 278/333 (83.5%) with no regression.
A mapping value's anchor or tag on the line below the key must be indented
past the key. The parser consumed such a property regardless of its column,
so 'seq:' then '&anchor' in column 1, anchoring a sequence at the document
level, parsed instead of failing.
When the value's properties are consumed before the indent check, a
properly indented one would have been preceded by an indent token and
consumed inside the indented value; reaching that point with a property on
a later line therefore means it sits at the key's indentation, which is
rejected. The indented-value branch and the new guard move to their own
helpers so parseMappingPair stays within the complexity and length limits.
An inline property, an indented property, and a block sequence at the key's
indent are unaffected.
Measured against the official YAML test-suite, parse-level conformance
rises from 275/333 (82.6%) to 276/333 (82.9%) with no regression.
A comment terminates a plain scalar, so a multi-line plain scalar cannot
resume after one. The parser accepted 'key: word1' then a '#' line then
' word2', and 'a' then 'b # ...' then 'c', merging the trailing content
back into the value ('word1 word2', 'a b c').
The scanner folds a genuine multi-line plain scalar into a single token
and splits it into a value-line scalar, an indent, and a further scalar
only when a comment broke its continuation folding. That token shape
therefore always denotes a comment-interrupted scalar, so the parser now
rejects it rather than re-merging. The re-merge path and its helper are
removed as they only ever served this malformed shape. A real multi-line
plain scalar and a trailing comment after a value stay valid.
Measured against the official YAML test-suite, parse-level conformance
rises from 264/333 (79.3%) to 266/333 (79.9%) with no regression.
A block mapping pair after the first could not carry an anchor or tag on
its key (k: 1 then &b key2: 2): the first pair's key properties are
consumed when the mapping is entered, but subsequent pairs were not, so an
anchored key past the first failed with 'expected mapping key, found
anchor'. The pair parser now consumes leading key properties for every
pair, attaching them to the key node, and a block mapping continues across
an anchor or tag token that begins a key.
Normal mappings, anchored values, sequences, and explicit keys are
unaffected. Measured against the official YAML test-suite, parse-level
conformance rises from 235/333 (70.6%) to 238/333 (71.5%), with no
regression.
The block mapping parser required a ':' after every explicit key ('? key'),
so a key with no value, including several '? key' entries in a row (a set),
failed to parse with 'expected mapping value'. An explicit key with no
following ':' now takes an implicit null value, shared with the existing
'key:'-with-nothing-after path via one emitNullMappingValue helper.
Explicit keys with values and complex keys in general are unaffected. A
test that asserted '? [a, b]' followed by a block entry is a missing-value
error was corrected: the key is a valid null entry, and the trailing
sequence is now rejected as extra content (a second root node), which is
the more accurate diagnosis.
Measured against the official YAML test-suite, parse-level conformance
rises from 229/333 (68.8%) to 235/333 (70.6%), with several of the newly
parsed documents also value-correct and no regression.
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.
