434c554 left an account that refuses to list its address books or
calendars out of the run, but reported it as an item error. The sync
settings then said "1 item could not be synced" after every run for an
account that merely shares a mailbox: nothing the user can fix, and no
item behind it. Such an account is now only logged.
Checked: the engine tests, `npm run typecheck` and `npm test` on this
commit, and the sync settings of usera on the API 32 emulator after a
new run.
Stalwart lists an account shared with the user for mail only with every
capability, and answers `forbidden` when the user asks for its address
books or calendars. The engine treated that like any failed request, so
on the local test server every sync of usera ended with an I/O error and
never reached the device, only because userb shares a mailbox.
An account that refuses to list its collections (`forbidden`,
`accountNotFound`, `accountNotSupportedByMethod`) is now left out of the
run and reported as an item error; the other accounts sync as before.
The rows written for such an account stay on the device: a refusal can
pass, and dropping the account's contacts and events for one refused
request would throw away device edits that are still waiting.
Checked: three new engine tests (a shared account that never listed,
one that stops listing its address books, one that stops listing its
calendars), which fail without the fix, `npm run typecheck` and
`npm test` on this commit, and a contacts sync of usera on the API 32
emulator, which now ends `ok` with one item error.
The sync adapters from ed2525e start a headless task for every sync, but
the task only reported "disabled". This adds the engine it runs
(`src/device-sync/engine`, `src/device-sync/jmap`): for one Android
account and authority it downloads the server's changes, uploads what
the device changed, and hands a report back to SyncManager.
- Downloads follow `/changes` from the state kept in the provider's
SyncState. Rows and the state they reach are written in one batch, so
a killed run resumes where it stopped. Without a state, after
`cannotCalculateChanges` or after the user discarded deletions, a full
reconcile compares ids instead.
- Uploads go in three phases across accounts (creates, updates,
deletions), so moving an item to another account never destroys it
before the copy exists. A create carries a uid written to the device
first, and the server is asked for that uid before creating, so a lost
response or a killed run never makes a duplicate. Updates are patches
guarded by `ifInState`; nothing is replaced whole.
- More than 50 deletions that are also more than a fifth of the synced
items hold every deletion back and report `tooManyDeletions`, so
Android asks the user; "undo" restores the items from the server.
- An item the server refuses is marked and not sent again until it
changes or its back-off (1 hour, doubling to a day) ends. Such
refusals and planner errors stay with their item; the rest of the run
goes on.
- Runs of one account and authority take a lock, stop at checkpoints
when cancelled or close to the deadline, and never throw: every
failure becomes an outcome, and a rejected sign-in posts one "Sign in
again" notification.
- The JMAP side uses a client of its own per app account, never the
UI's, since a run can share the JS runtime with the app.
Turning sync off or signing out runs the same upload first
(`teardownAuthority`) and deletes the rows only once nothing is waiting,
or when the user agreed to lose it.
The planners that map items to rows land in the next commits; until
then a run fails before it touches a row.
Checked: 94 engine tests against the fake provider and JMAP server
(sync flows, failures, crashes and retries, teardown), and `npm run
typecheck`, `npm test` and `npm run i18n:check` on this commit.