A hand-rolled content-line model instead of ical4j: a raw (name, params,
value) tree is what the round-trip requirement wants, and a typed model
normalises away exactly what has to survive. lib-recur already does RRULE
and java.time is native at minSdk 29, so the 2.2 MB of zone data and the
registry shims buy nothing. Deviates from SYNC.md's library table — see
SYNC-PLAN.md decision 4.
- domain/ical: parser, serialiser, value codecs. No Android, no data types,
so the floret-kit extraction stays a file move.
- data/tasks/ical/VTodoMapper: VTODO <-> TaskEntity. Claims a property only
when it can reproduce it exactly; everything else round-trips verbatim
through TaskEntity.unknown_properties, which already existed at v1 — no
migration needed, and BEGIN/END lines carry the nesting the plan thought
needed a second table.
- 19 fixtures as the specification, with the canonical comparison harness
from SYNC.md: no property lost, modulo the enumerated allowlist.
- ICalendarWriter now delegates folding and escaping rather than carrying
its own copy.
VALARM ownership settled: neither side writes the other's alarms. VALARMs
round-trip in the residue, local reminders stay in task_alarms. The
setAlarm collision was the provider's; the two stores are now disjoint.
SYNC.md decides; it doesn't sequence. SYNC-PLAN.md turns its ~40 scattered
findings into five chunks — mapper, auth/discovery, engine core, incremental
sync + scheduling, hardening — each with a done-when and the traps it must
not get wrong.
Closes SYNC.md's three open questions: vendor dav4jvm/cert4android at our
Java 17 target, server-wins-and-report on 412, External mode stays.
makiolaj