handling of core.composeEmail errors

[tomholub]

It's possible for this to fail for various reasons. For example, try to run this with an invalid public key. It will produce an error, and this should be handled gratiously - by showing a modal alert to the user that there was an error sending message, and what it said. After the taps clicks the modal away, they should still be on the compose screen where they can click send again to retry.

Originally posted by @tomholub in #410 (comment)

 private func encryptMessage(with msg: SendableMsg) -> Data {
 do {
 return try core.composeEmail(msg: msg, fmt: MsgFmt.encryptInline, pubKeys: msg.pubKeys).mimeEncoded
 } catch {
 fatalError()
 }
 }

[ivan-ushakov]

Looks like this was changed a lot because now it uses Compose to provide future object:

func composeEmail(msg: SendableMsg, fmt: MsgFmt, pubKeys: [String]?) -> Future<CoreRes.ComposeEmail, Error>

and in ComposeMessageService:

private func encryptMessage(with msg: SendableMsg) -> AnyPublisher<Data, Error>

and in ComposeViewController it has error handler and alert.

[tomholub]

I see it now - could you check what happens when you give it some bogus pubkey to trigger an error?

 private func encryptMessage(with msg: SendableMsg) -> AnyPublisher<Data, Error> {
 return core.composeEmail(
 msg: msg,
 fmt: MsgFmt.encryptInline,
- pubKeys: msg.pubKeys
+ pubKeys: ["This is bogus!"]
 )
 .map(\.mimeEncoded)
 .eraseToAnyPublisher()
 }

It should surface the error to the user as a modal in a generic manner.

[ivan-ushakov]

Do you have any test user for the app? Maybe some kind of test account?

[tomholub]

Do you have any test user for the app? Maybe some kind of test account?

Yes, I'll just need an NDA signed if that is ok with you. You'll get your own account on flowcrypt.com domain that you can test with, and also some general test accounts. Also test secrets to run UI tests.

[ivan-ushakov]

OK, I will contact you tomorrow about NDA.

[ivan-ushakov]

Here is how it looks:

but I found that error handling happens off the main thread:

Main Thread Checker: UI API called on a background thread: -[UIViewController navigationItem]
PID: 71426, TID: 8735387, Thread name: (none), Queue name: com.flowcrypt.core, QoS: 9
Backtrace:
4 FlowCrypt 0x000000010c4320dd $s9FlowCrypt21ComposeViewControllerC6handle33_7A1ECDF8A8586BF8F0F21A8909AD61B9LL5erroryAA0C12MessageErrorO_tF + 157
5 FlowCrypt 0x000000010c432028 $s9FlowCrypt21ComposeViewControllerC11sendMessage33_7A1ECDF8A8586BF8F0F21A8909AD61B9LLyyFyAA0cG5ErrorOcfU0_ + 232
6 FlowCrypt 0x000000010c43231c $s9FlowCrypt19ComposeMessageErrorOIegg_ACIegn_TR + 28
7 FlowCrypt 0x000000010c2f4fe3 $s7Combine9PublisherP9FlowCryptE10sinkFuture12receiveValue0G5ErrorAA14AnyCancellableCy6OutputQzc_y7FailureQzctFyAA11SubscribersO10CompletionOy_AMGcfU_ + 435
8 Combine 0x00007fff4e90e216 $s7Combine11SubscribersO4SinkC7receive10completionyAC10CompletionOy_q_G_tF + 422

I will fix this.