#143 added a device-local flag recording that background notifications were
switched on in this browser, and made the renewal on app start key off it. It
is not in KEEP_ON_SIGN_OUT, and that is the whole bug: clearSignedInData()
runs on two different endings and only one of them is a sign-out.
The other is a session expiring, which is what a deploy does to every signed-in
browser at once. That path deliberately does not remove the push subscription
-- there is no session left to remove it with -- so the subscription stays
registered at Stalwart and the browser keeps its own. Losing the flag there
left nothing to renew them: push would have gone quiet a week after every
deploy, with the switch in Settings still reading as on because both ends of
the subscription still existed. That is the exact failure #143 was written to
prevent, reintroduced through a different door, and the first deploy carrying
#143 would have been the thing that triggered it.
Signing out for real still forgets it. That happens directly in
unsubscribeThisDevice, next to destroying the subscription, and it happens even
when the server cannot be reached -- a browser that goes on believing it has
push would have renewal resurrect it on the next sign-in.
Both halves are tested now, because they are one invariant seen from two sides:
storage.test.ts covers the flag surviving an expiry, webpush.test.ts covers a
sign-out clearing it with the server unreachable.
Sign-out never cleared local storage. It stopped push, flushed settings and
removed the subscription -- that last one reasoned explicitly that a browser
left holding someone's mail becomes somebody else's next -- and then left the
settings cache and the recently-addressed list on disk. That list is other
people's addresses, and nothing ever removed it.
Clearing it on sign-out is now unconditional, because lending a laptop is the
same exposure as a public machine, only quieter. The keep-list is short and
deliberate: lastUser, which only a trusted device writes; the trust flag; and
the random push device id. Everything else goes, so a key added later is
forgotten by default rather than by nobody having thought about it.
"Keep me signed in on this device" defaulted to true, which assumed the answer
most costly to get wrong -- someone on a library machine got a thirty-day
cookie unless they noticed a ticked box. It now asks whose computer this is,
defaults to not yours, and says what each answer does. Untrusted means a
session cookie, nothing written locally, no push subscription, and a five
minute idle sign-out.
The idle timer is there because the alternative does not work: custom
beforeunload text was removed from browsers years ago, and no event fires at
all for walking away from a signed-in screen, which is the case that matters.
A timer needs nobody's cooperation.
Reads are gated as well as writes, since a machine trusted once still has the
residue; an untrusted sign-in purges it outright. The wire keeps calling this
`remember` -- it is persisted in SESSION_FILE, and renaming it would invalidate
every session file on upgrade for a change of vocabulary.
Verified in a browser against the mock, not only in tests: untrusted sign-in
leaves localStorage empty through a full session including folder expansion;
trusted writes settings, recent and lastUser as before; sign-out clears recent
and settings while keeping lastUser; an untrusted sign-in afterwards clears
even that.
jcoffey-dev