The point-fix (7a7b840e) excluded only `indent: 0` via a hardcoded one-attribute
denylist (`DEFAULT_KEY_ATTRS`) applied solely to ELEMENT attributes. The same
divergence recurs for every attribute whose editor-ext (server) schema default the
LIVE Yjs doc materializes (`TiptapTransformer.toYdoc(tiptapExtensions)`) but the
git round-trip does not: the engine's `markdownToProseMirror` emits those attrs as
explicit `null` (verified live: link mark `internal: null`, heading/paragraph
`indent: null`), which `y-prosemirror` then drops — so the same block keys
differently on the two sides, the three-way merge anchors on nothing, and the body
is re-appended every reconcile cycle (unbounded, no client connected). The denylist
also could not reach MARK attributes at all (marks are serialized raw in the
XmlText delta), so the link mark's `internal` mismatch survived.
Replace the denylist with a normalization derived from the ACTUAL ProseMirror
schema (`getSchema(tiptapExtensions)`, memoized): in `serializeXmlNode`, drop any
ELEMENT attribute whose value equals its node's schema default (or is
null/undefined), and normalize each XmlText delta op's MARK attributes the same way
against `schema.marks[name].spec.attrs`. The volatile block `id` stays excluded and
genuine non-default values (a real `indent: 2`, `align: "left"`, `link.href`,
highlight color) stay in the key. This is general — it covers indent, image.align,
link.internal, highlight.colorName, youtube/pdf and any future node/mark — not
another per-attribute denylist. Schema build is wrapped so a degenerate test stub
(`tiptapExtensions: []`) degrades to dropping only null/undefined.
Tests: new `yjs-body-merge.schema-defaults.spec.ts` models image/link/highlight
both hand-built and through the REAL `TiptapTransformer.toYdoc` materialization
(live defaults vs engine-style explicit nulls, base stale-by-one) — RED before
(4 ops / growth), GREEN after (0 ops). Existing idempotency + open-editor
convergence suites still pass (261 server collab+git-sync tests, tsc clean).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
907be19390