A document-end marker takes no node on its own line: only a comment or
blank may follow. The scanner skipped the rest of the marker's line, so
content such as the 'invalid' in '... invalid' was silently dropped and
the document accepted.
scanDocumentMarker now distinguishes the two markers after skipping spaces:
a document start may carry the root node on its line and leaves it for the
main loop, while a document end rejects any real content (a comment or
blank still passes). A '...' not followed by an indicator boundary is not
a marker at all and remains an ordinary plain scalar, so '...junk' still
parses as content.
Measured against the official YAML test-suite, parse-level conformance
rises from 255/333 (76.6%) to 256/333 (76.9%) with no regression.
Mihaela M
fcba4e1f57