mathiasandClaude Sonnet 5
874206be9d
Second review round on PR #126 found two more problems with the first append fix: 1. When a has no frontmatter fence at all, the fallback spliced raw, unfenced "key: value" text straight into the body -- worse than the original bug, since the next parseSections call wouldn't recognize it as frontmatter and would absorb it as preamble text, duplicating on every subsequent merge. 2. The regression test only asserted substrings (Contains), which doesn't prove structural position. Two independent mutations (closeIdx locking onto the wrong fence, a reversed sort) both survived the full suite undetected. Rewritten from string-index surgery (tracking a fence's position across two passes over split lines) to a small parsed representation: fmLine (key/value or raw), parseFrontmatterBlock, setLine (update in place or append -- the one behavior the original code got wrong), and renderFrontmatterBlock. Same shape as the sibling api package's own frontmatter type, reproduced locally rather than imported (it's unexported there, and this package's needs are smaller) because that set()-appends-if-absent behavior was already proven correct by that package's existing test suite -- this bug class shouldn't have existed here in the first place. A page with no fence gets one created to hold the new fields, instead of corrupting the body. Tests now assert exact frontmatter block output via assert.Equal, not Contains, and a new fixture (mixed replace+append in one call) covers both code paths together. Flip-tested: reversing the sort turns two of the new exact-match tests red (the Contains-based version of the same test missed this on the prior commit). The "wrong fence" bug class is now structurally impossible rather than merely untested -- there's no fence-position index left to get wrong. Also fixed a byte-stability regression the new render introduced and caught via the full pipeline suite: a key with no inline value (the YAML block-list shape, "aliases:" followed by indented "- item" lines) rendered as "aliases: " (trailing space) instead of "aliases:". Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>