agent: fix acceptContact inconsistent state after app restart (#1412)

Author: spaced4ndy

src/Simplex/Messaging/Agent.hs

@@ -687,9 +687,15 @@ allowConnectionAsync' c corrId connId confId ownConnInfo =
       enqueueCommand c corrId connId (Just server) $ AClientCommand $ LET confId ownConnInfo
     _ -> throwE $ CMD PROHIBITED "allowConnectionAsync"
 
+-- TODO
+-- Unlike `acceptContact` (synchronous version), `acceptContactAsync` uses `unacceptInvitation` in case of error,
+-- because we're not taking lock here. In practice it is less likely to fail because it doesn't involve network IO,
+-- and also it can't be triggered by user concurrently several times in a row. It could be improved similarly to
+-- `acceptContact` by creating a new map for invitation locks and taking lock here, and removing `unacceptInvitation`
+-- while marking invitation as accepted inside "lock level transaction" after successful `joinConnAsync`.
 acceptContactAsync' :: AgentClient -> ACorrId -> Bool -> InvitationId -> ConnInfo -> PQSupport -> SubscriptionMode -> AM ConnId
 acceptContactAsync' c corrId enableNtfs invId ownConnInfo pqSupport subMode = do
-  Invitation {contactConnId, connReq} <- withStore c (`getInvitation` invId)
+  Invitation {contactConnId, connReq} <- withStore c $ \db -> getInvitation db "acceptContactAsync'" invId
   withStore c (`getConn` contactConnId) >>= \case
     SomeConn _ (ContactConnection ConnData {userId} _) -> do
       withStore' c $ \db -> acceptInvitation db invId ownConnInfo
@@ -809,7 +815,7 @@ newConnToJoin c userId connId enableNtfs cReq pqSup = case cReq of
 
 newConnToAccept :: AgentClient -> ConnId -> Bool -> ConfirmationId -> PQSupport -> AM ConnId
 newConnToAccept c connId enableNtfs invId pqSup = do
-  Invitation {connReq, contactConnId} <- withStore c (`getInvitation` invId)
+  Invitation {connReq, contactConnId} <- withStore c $ \db -> getInvitation db "newConnToAccept" invId
   withStore c (`getConn` contactConnId) >>= \case
     SomeConn _ (ContactConnection ConnData {userId} _) ->
       newConnToJoin c userId connId enableNtfs connReq pqSup
@@ -941,13 +947,12 @@ allowConnection' c connId confId ownConnInfo = withConnLock c connId "allowConne
 -- | Accept contact (ACPT command) in Reader monad
 acceptContact' :: AgentClient -> ConnId -> Bool -> InvitationId -> ConnInfo -> PQSupport -> SubscriptionMode -> AM SndQueueSecured
 acceptContact' c connId enableNtfs invId ownConnInfo pqSupport subMode = withConnLock c connId "acceptContact" $ do
-  Invitation {contactConnId, connReq} <- withStore c (`getInvitation` invId)
+  Invitation {contactConnId, connReq} <- withStore c $ \db -> getInvitation db "acceptContact'" invId
   withStore c (`getConn` contactConnId) >>= \case
     SomeConn _ (ContactConnection ConnData {userId} _) -> do
+      sqSecured <- joinConn c userId connId enableNtfs connReq ownConnInfo pqSupport subMode
       withStore' c $ \db -> acceptInvitation db invId ownConnInfo
-      joinConn c userId connId enableNtfs connReq ownConnInfo pqSupport subMode `catchAgentError` \err -> do
-        withStore' c (`unacceptInvitation` invId)
-        throwE err
+      pure sqSecured
     _ -> throwE $ CMD PROHIBITED "acceptContact"
 
 -- | Reject contact (RJCT command) in Reader monad

src/Simplex/Messaging/Agent/Client.hs

@@ -2020,7 +2020,7 @@ storeError = \case
   SEConnDuplicate -> CONN DUPLICATE
   SEBadConnType CRcv -> CONN SIMPLEX
   SEBadConnType CSnd -> CONN SIMPLEX
-  SEInvitationNotFound -> CMD PROHIBITED "SEInvitationNotFound"
+  SEInvitationNotFound cxt invId -> CMD PROHIBITED $ "SEInvitationNotFound " <> cxt <> ", invitationId = " <> show invId
   -- this error is never reported as store error,
   -- it is used to wrap agent operations when "transaction-like" store access is needed
   -- NOTE: network IO should NOT be used inside AgentStoreMonad

src/Simplex/Messaging/Agent/Store.hs

@@ -623,7 +623,7 @@ data StoreError
   | -- | Confirmation not found.
     SEConfirmationNotFound
   | -- | Invitation not found
-    SEInvitationNotFound
+    SEInvitationNotFound String InvitationId
   | -- | Message not found
     SEMsgNotFound
   | -- | Command not found

src/Simplex/Messaging/Agent/Store/SQLite.hs

@@ -926,9 +926,9 @@ createInvitation db gVar NewInvitation {contactConnId, connReq, recipientConnInf
       |]
       (invitationId, contactConnId, connReq, recipientConnInfo)
 
-getInvitation :: DB.Connection -> InvitationId -> IO (Either StoreError Invitation)
-getInvitation db invitationId =
-  firstRow invitation SEInvitationNotFound $
+getInvitation :: DB.Connection -> String -> InvitationId -> IO (Either StoreError Invitation)
+getInvitation db cxt invitationId =
+  firstRow invitation (SEInvitationNotFound cxt invitationId) $
     DB.query
       db
       [sql|