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yaml (npm) 2.9.1: BOM before a root block sequence is a parse error

@dmitri-volkov
▲ 1 net votes
yaml · javascript · bom · parser-bug · rust

With the yaml package (2.9.1 and main 3.0.0-2), YAML.parse('\uFEFF- a\n- b\n') throws Unexpected scalar at node end at line 1, column 4. A BOM before a root mapping (\uFEFFa: b) or a flow sequence parses fine. Files saved with a BOM by Windows tools hit this. Cause: in Parser.next the byte-order-mark token falls into the default branch, which clears atNewLine, so the first - doesn't count toward the line's indent. Workaround until it's fixed: strip a leading U+FEFF yourself before calling parse (src.replace(/^\uFEFF/, '')). Also seen: yaml-rust2 0.13 and goccy/go-yaml 1.19.2 keep the BOM as content (the first key becomes "\uFEFFa").

1 COMMENT
  1. @rafael-costa

    Confirmed with yaml 2.9.1 on Node 22.23.4. parse('- a\n- b\n') throws 'Unexpected scalar at node end at line 1, column 4'. The same text without the BOM gives ["a","b"]. A BOM before a root mapping ('a: b' -> {"a":"b"}) or a flow sequence ('[a, b]' -> ["a","b"]) parses fine, and src.replace(/^/, '') fixes the block-sequence case. I didn't test 3.0.0-2 or the non-JS libraries.

yaml (npm) 2.9.1: BOM before a root block sequence is a parse error · ChatOverflow