RFC 6578 as an optimisation on top of chunk 3's full path, and sync that runs
by itself.
- :caldav gains sync-collection, with invalidation matched on
DAV:valid-sync-token in the body on any 4xx rather than on a status code —
400, 403, 409 and 412 are all used in the wild, and matching the status is
why Thunderbird never recovers from sabre's 403. No DAV:limit (Nextcloud
regressed it to an HTML error page); 507 on our own href is truncation.
- The engine persists the token per page, after the bodies. An iteration cap
and a no-progress guard, since the RFC never requires the token to advance.
The full path runs anyway every 24h: a token the server accepts over a
pruned change log returns 207, zero changes and no error, and the protocol
gives no other way to notice.
- The three membership traps: an unknown removed href is a no-op, a
delete-then-recreate is re-identified from the UID in the body, and a mass
removal is refused in favour of a real listing, because ACL churn looks
exactly like one.
- Scheduling is a PeriodicWorkRequest with a network constraint, expedited
only for the in-app button. getForegroundInfo is implemented unconditionally
(setExpedited falls back to a foreground service below API 31 and the
default throws) but declares no service type, which would have pulled back
the Android 15 dataSync budget and a Play video-demo requirement.
initialIncomplete turned out not to be needed: adopting a token only after a
full reconciliation completes removes the hazard it guarded, so there is
nothing to persist atomically with anything.
/code-review high raised 8 findings, all fixed. The two that mattered: the
cadence clock sat in the backed-up DataStore, so a restore would have made the
engine trust a stale token for a day — both sync-state stores now have their
own excluded file; and the incremental download path lacked the write-phase
guard, overwriting local edits that had never reached the server. Reasoning in
docs/SYNC-PLAN.md.
Chunk 2's on-device review is still outstanding; none of this has run on a
device or against a real server.
Full bidirectional sync, correct but not yet clever: calendar-query with no
time-range, calendar-multiget in batches matched against what was asked for,
conditional writes, and per-resource quarantine so one bad task cannot stop a
collection.
- :caldav gains CalendarCollection (list/fetch/create/update/delete + the
three-way 412 triage), ETag with its weak flag, vdirsyncer-style resource
names, and the RemoteCalendar seam.
- CalDavHttp now sends Accept-Encoding: identity and Prefer: handling=strict,
the two headers that keep ETags strong and our bytes unrepaired.
- :app gains CollectionSyncer (the reconciliation), SyncEngine, SyncStore,
QuarantineStore, SyncReport and a working SyncWorker, plus an in-app sync
trigger since ContentResolver.requestSync is gated at our targetSdk.
- VTimeZones closes a chunk-1 gap: the mapper emitted TZID with no VTIMEZONE
to resolve it, which handling=strict turns from a repair into a rejection.
/code-review high raised 11 findings, all fixed. The three that mattered:
an empty listing swept the whole list (a VTODO comp-filter some servers
mishandle is not proof of deletion, so an empty listing now never sweeps);
quarantine never covered creates, so a permanently rejected new task was
re-PUT forever; and a RELATED-TO deleted on the server was re-uploaded on the
next edit. Reasoning recorded in docs/SYNC-PLAN.md.
Chunk 2's on-device review is still outstanding; nothing here has been run on
a device or against a real server.
One flow, one back-stack entry, as a stepper rather than four destinations —
the steps are not independently reachable, and "back" from the browser step
abandons a server-side flow rather than popping a screen. It hangs off Settings
with the same sliding-section pattern Storage -> Export uses.
address -> discovery -> (Nextcloud browser approval | username + password)
-> pick lists -> add account
Provider warnings come before the attempt, not after: type a Fastmail or iCloud
address and the app password rule is stated while you type, which is the single
most common support ticket a CalDAV client inherits. Google is refused with the
reason. A login-flow host mismatch is shown, not refused — reverse proxies are
ordinary on self-hosted installs.
PreemptiveBasicInterceptor is deleted. The vendored BasicDigestAuthHandler
already sends Basic preemptively over HTTPS, also does Digest (Baikal defaults
to it, OkHttp has none), caches the working scheme, and scopes by registrable
domain — which is what iCloud's cross-host home set needs. Two implementations
of one job is the defect chunk 1 removed from ICalendarWriter.
⚠️ That handler compares its `domain` against the *registrable* domain, so
passing the full host meant credentials were withheld from every request to
every subdomain — i.e. every self-hosted Nextcloud, silently 401ing forever.
Pinned by CalDavHttpTest.
CalDavGateway and AccountCreator put the network and the database behind
interfaces so the sign-in state machine is testable without a server, a
database, a Keystore or an AccountManager. It had no tests, and the review
found eight issues in it.
Account creation is transactional and rolls its lists back explicitly:
account_id is ON DELETE SET NULL, so deleting the row alone leaves orphan
lists behind and every retry adds another set.
The platform half of chunk 2; the account-add UI is 2d, since it is a design
task and the piece that needs an on-device review.
A stub ContentProvider turned out to be required and was not in the plan: a
sync adapter registers against a content authority, and we publish no provider
since :provider was deleted. Without one there is nothing for contentAuthority
to name, nothing for requestSync to address, and hasAuthorityAccess() makes
every ContentResolver sync call a silent no-op at targetSdk 34+.
- CredentialStore: Keystore AES/GCM, blob in its own DataStore file.
security-crypto is formally deprecated and terminal. Decryption failure means
re-authenticate, never a crash — including ProviderException, which is a
RuntimeException and escapes the obvious catches.
- CalDavAccounts + SyncAuthenticator: no password reaches AccountManager, which
stores them as plain TEXT. The authenticator never returns null — a null is
the protocol for "answering asynchronously", and nothing here does, so
Settings would wait forever. addAccount refuses with a readable message until
2d ships the screen, rather than opening the home screen and hanging.
- SyncAdapterService: enqueue and wait on the unique work *name*, not the
request id — enqueueUniqueWork is async so the id is unknown when the wait
starts, and under KEEP it may never exist at all. Being deduplicated is not
a failure.
- Account type and authority are per build variant, so debug and release do
not fight over ownership. SyncContractTest guards the Kotlin/resValue pair.
- The credential blob is the only thing excluded from backup: Keystore keys are
non-exportable, so a restored ciphertext can never be decrypted.
Known trade-off recorded in network_security_config.xml and SYNC-PLAN.md: the
user CA store is trusted for all traffic, which chunk 5's cert4android should
replace rather than sit beside.
The instrumented tests here compile but have not been run — device work waits
for an explicit go-ahead.
New :caldav module — MIT, plain JVM, api-depends on :dav. Separate from the
vendored MPL tree so the licences stay unmixed, and so "no Android types" is a
compile-time guarantee rather than a discipline. Chunk 2 split again: the
Android account layer (Keystore, AccountManager, Custom Tabs, account-add UI)
is 2c, with different verification and an on-device review.
- ServiceDiscovery: the RFC 6764 ladder. SRV priority/weight, TXT path=,
non-443 ports, "." targets, well-known then root.
- CollectionClassifier: the two filters that are inversions of the obvious
rule. An absent or empty supported-calendar-component-set means "supports
everything", and classification is a positive test for CALDAV:calendar on an
unordered set — excluding schedule-outbox would drop SOGo's main calendar.
- CalDavDiscovery: OPTIONS gate, principal, every home set, Depth-1 by name.
A failing home set does not fail the account, and every home set failing is
reported as an error rather than as an account with no lists.
- NextcloudLoginFlow: POST not GET, a User-Agent the user can recognise when
revoking, 404-means-pending only, both URLs origin-checked, host mismatch
carried rather than refused (reverse proxies are ordinary).
- PreemptiveBasicInterceptor, ServerQuirks.
dnsjava 3.6.3 (BSD-3) added: Android's DnsResolver is callback-only and cannot
do the TXT path lookup, and JNDI's DNS provider does not exist on Android.
Behind an interface, so every trap is tested with a fake and no network.
:dav gains change 6 — <D:unauthenticated/> is parsed rather than inferred from
a null href, which also fires on a merely non-conformant empty element.
52 tests here, 78 in :dav. SYNC.md's live-probed trap table is executable now.
JitPack-only publishing conflicts with FAIL_ON_PROJECT_REPOS, artifacts are
unsigned and not immutable, and upstream shipped two breaking majors 19 days
apart. 2.2.1 is the last OkHttp release: 3.0.0 moved to Ktor and 4.x needs
Java 21, and SYNC.md's whole auth section is written in OkHttp terms, so 4.x
would have invalidated it. A plain JVM module, not an Android library — the
tree has no Android imports and keeping it that way keeps the floret-kit
extraction a file move.
Four changes from upstream, all in dav/PROVENANCE.md:
- commons-lang3 dropped (one import, one call). The replacement requires the
whole string to be consumed, as DateUtils did: pattern 1 ends in a literal
'GMT', so SimpleDateFormat would match "...GMT+02:00" as a prefix and throw
the offset away.
- HTTP dates were parsed and formatted in the device's local zone — the GMT in
the format string is a quoted literal and timeZone was never set, so every
getlastmodified was out by the local UTC offset. Upstream tests dates
nowhere. The formatter is also no longer shared and mutable.
- dav4jvm#209: permanent redirects now reach the caller via
DavResource.permanentLocation, cleared per request so it never describes an
earlier one.
- xpp3 is compileOnly; Android supplies org.xmlpull.v1.
SYNC.md's other claimed defect, "does not follow 303", is not true of 2.2.1 —
pinned by a test rather than removed from the notes.
CI names :dav:test explicitly; testDebugUnitTest is Android-only and would
have run none of the vendored suite. lintDebug added to the per-chunk checks
after it caught a literal byte-order mark left by chunk 1.
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