Assert parse failures

Some messages with emojii aren't parsing, log and discard them.

README.md

@@ -21,6 +21,7 @@ Probably a front for gathering metadata, like Signal, except FSB.
 let ?ds = dataspace
 
 ? <service-object <daemon telegram_actor> ?cap> [
+  $cap ? <telegram-recv-error ?err> [ $log ! <log "-" { telegram-recv-error: $err }> ]
   $cap <telegram-client { dataspace: $ds }>
 ]
 

src/telegram_actor.nim

@@ -11,8 +11,10 @@ discard td_execute("""{"@type":"setLogVerbosityLevel", "new_verbosity_level":0}"
 
 type State = ref object
   facet: Facet
+  initialRef: Cap
   subscribers: Table[int, Cap]
   buffer: StringStream
+  recvError: Handle
 
 let state = State( buffer: newStringStream() )
   # Global state object
@@ -20,6 +22,7 @@ let state = State( buffer: newStringStream() )
 let actor = bootActor("main") do (turn: Turn):
   state.facet = turn.facet
   resolveEnvironment(turn) do (turn: Turn; ds: Cap):
+    state.initialRef = ds
 
     during(turn, ds, TelegramArguments.grabTypeFlat) do (ds: Cap):
       # Extern actors assert themselves here and a ClientId
@@ -47,14 +50,8 @@ proc recv(state: State; id: int; recvMsg: Value) =
     queueTurn(state.facet) do (turn: Turn):
       message(turn, subscriber, recvMsg)
 
-while actor.running:
-  # Poll Syndicate and Telegram
-  const
-    syndicateTimeout = some initDuration(seconds = 4)
-    telegramTimeout = 4.0
-  syndicate.runOnce(syndicateTimeout)
-  let cstr = td_receive(telegramTimeout)
-  if not cstr.isNil:
+proc recv(state: State; cstr: cstring) =
+  try:
     var
       pr = parsePreserves $cstr
       clientId: Value
@@ -63,3 +60,20 @@ while actor.running:
       recv(state, clientId.register, initRecord("recv", pr))
     else:
       stderr.writeLine "discarding message without @client_id: ", cstr
+  except ValueError:
+    var buf = newSeq[byte](cstr.len)
+    copyMem(buf[0].addr, cstr[0].addr, buf.len)
+    var rec = initRecord("telegram-recv-error", buf.toPreserves)
+    stderr.writeLine rec
+    queueTurn(state.facet) do (turn: Turn):
+      replace(turn, state.initialRef, state.recvError, rec)
+
+while actor.running:
+  # Poll Syndicate and Telegram
+  const
+    syndicateTimeout = some initDuration(seconds = 4)
+    telegramTimeout = 4.0
+  syndicate.runOnce(syndicateTimeout)
+  let cstr = td_receive(telegramTimeout)
+  if not cstr.isNil:
+    recv(state, cstr)