Approve-with-comments auto-review (8 axes); no blockers. Closes the two flagged
test gaps; the two forward-looking dedup suggestions (reconcileHasChildren helper;
unifying reconcileChildren/mergeRootTrees) are non-blocking architecture notes and
left for a follow-up (as with #186's forward-looking point).
1. Ambiguous-id refusal end-to-end (#159): the patch_node/delete_node guard
`if (replaced/deleted !== 1) return null` was only covered in pieces — the
replaceNodeById/deleteNodeById counts and assertUnambiguousMatch in isolation —
so loosening the guard would not have failed a test. New mock test stands up a
REAL Hocuspocus collab server seeded (via buildYDoc, same docmost extensions)
with a two-blocks-one-id document and drives the real client methods: both must
reject with /ambiguous/ AND never write to collab. Tracked via Hocuspocus
onChange (fires synchronously per update, unlike the debounced onStoreDocument)
so a clobbering write is actually observed — verified the test FAILS when the
guard is loosened to `< 1`.
2. scrollToReference zero-match bail: the branch "non-empty id but querySelectorAll
returns 0 -> matches[index] ?? matches[0] is undefined -> return false" (the real
desync: definition present, inline ref removed from the DOM) was uncovered. Added
a footnote.test.ts case: a definition for 'ghost' with no rendered ref -> false,
no scroll.
Verified: 313 mcp tests + 24 editor-ext footnote tests; prettier clean.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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