Be more pedantic with error handling

tractor/_portal.py

@@ -358,12 +358,14 @@ class Portal:
 
         fn_mod_path, fn_name = func_deats(func)
 
+
+        try:
             cid, recv_chan, functype, first_msg = await self._submit(
                 fn_mod_path, fn_name, kwargs)
 
             assert functype == 'context'
-
             msg = await recv_chan.receive()
+
             try:
                 # the "first" value here is delivered by the callee's
                 # ``Context.started()`` call.
@@ -377,14 +379,18 @@ class Portal:
                     raise unpack_error(msg, self.channel)
                 else:
                     raise
-        try:
+
+            # deliver context instance and .started() msg value in open
+            # tuple.
             ctx = Context(self.channel, cid, _portal=self)
+            try:
                 yield ctx, first
 
             finally:
-            await recv_chan.aclose()
                 await ctx.cancel()
 
+        finally:
+            await recv_chan.aclose()
 
 @dataclass
 class LocalPortal:

tractor/_trionics.py

@@ -357,7 +357,8 @@ async def open_nursery(
     try:
         if actor is None and is_main_process():
 
-            # if we are the parent process start the actor runtime implicitly
+            # if we are the parent process start the
+            # actor runtime implicitly
             log.info("Starting actor runtime!")
 
             # mark us for teardown on exit
@@ -376,7 +377,6 @@ async def open_nursery(
             async with _open_and_supervise_one_cancels_all_nursery(
                 actor
             ) as anursery:
-
                 yield anursery
 
     finally: