Do not count a leading BOM as a column (#334) - #345
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When the input encoding is set explicitly with yaml_parser_set_encoding, the reader does not strip a leading BOM, so the scanner skips it in yaml_parser_scan_to_next_token. SKIP() advances mark.column, so the first real token started at column 1 instead of 0, and a root-level block mapping then failed to parse with "did not find expected <document start>". Per YAML 1.2 section 5.2 a BOM is not content and must not advance the column. Reset mark.column to 0 after skipping the BOM. Add a regression test. Fixes yaml#334
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Fixes #334.
Problem
When the input encoding is set explicitly with
yaml_parser_set_encoding()(e.g.YAML_UTF8_ENCODING), the reader'sdetermine_encoding()BOM stripping is skipped, so a leading BOM reaches the scanner.yaml_parser_scan_to_next_token()skips it withSKIP(parser)— butSKIPincrementsparser->mark.column, so the first real token starts at column 1 instead of 0. A root-level block mapping then terminates at the first newline and parsing fails withdid not find expected <document start>. Per YAML 1.2 section 5.2 a BOM is not content and must not advance the column. The same input parses correctly underYAML_ANY_ENCODING(where the BOM was already stripped upstream).Fix
Reset
mark.columnto 0 after skipping the BOM, so the following token starts at column 0.Test
Added
tests/test-bom.c(registered inMakefile.amandCMakeLists.txt, followingtest-nesting): it parses"\xEF\xBB\xBF" "a: b\nc: d\n"under bothYAML_UTF8_ENCODINGandYAML_ANY_ENCODINGand asserts both fully parse the two-entry mapping. Red-green verified: before the fix the explicit-UTF-8 case fails (did not find expected <document start>), after the fix both pass. The existingtest-reader/test-nesting/test-versionstill pass, and parser-token output is byte-identical to the unmodified build acrossexamples/*.yaml(the fix only affects the BOM-at-column-0 path).