First draft, `asyncio`-task, sync-pausing Bo

Mostly due to magic from @oremanj where we slap in a little bit of
`.from_asyncio`-type stuff to run a `trio`-task from `asyncio.Task`
code!

I'm not gonna go into tooo too much detail but basically the primary
thing needed was a way to (blocking-ly) invoke a `trio.lowlevel.Task`
from an `asyncio` one (which we now have with a new
`run_trio_task_in_future()` thanks to draft code from the aforementioned
jefe) which we now invoke from a dedicated aio case-branch inside
`.devx._debug.pause_from_sync()`. Further include a case inside
`DebugStatus.release()` to handle using the same func to set the
`repl_release: trio.Event` from the aio side when releasing the REPL on
exit cmds.

Prolly more refinements to come ;{o

examples/debugging/asyncio_bp.py

@@ -83,13 +83,15 @@ async def main(
         debug_mode=True,
         maybe_enable_greenback=True,
         # loglevel='devx',
+        # loglevel='runtime',
     ) as n:
+
         ptl: Portal = await n.start_actor(
             'aio_daemon',
             enable_modules=[__name__],
             infect_asyncio=True,
             debug_mode=True,
-            # loglevel='cancel',
+            loglevel='cancel',
         )
 
         async with ptl.open_context(

tractor/devx/_debug.py

@@ -2491,7 +2491,10 @@ def pause_from_sync(
                     message += (
                         f'-> called from a root-actor bg {thread}\n'
                     )
-
+                elif is_aio:
+                    message += (
+                        f'-> called from a `asyncio`-task bg {thread}\n'
+                    )
                 message += (
                     '-> scheduling `._pause_from_bg_root_thread()`..\n'
                 )
@@ -2513,6 +2516,7 @@ def pause_from_sync(
                             **_pause_kwargs,
                         ),
                     ),
+                    trio_token=trio.lowlevel.current_trio_token(),
                 )
                 DebugStatus.shield_sigint()
                 message += (
@@ -2548,7 +2552,6 @@ def pause_from_sync(
         elif is_aio:
             greenback: ModuleType = maybe_import_greenback()
             repl_owner: Task = asyncio.current_task()
-            DebugStatus.shield_sigint()
             fute: asyncio.Future = run_trio_task_in_future(
                 partial(
                     _pause,
@@ -2564,7 +2567,6 @@ def pause_from_sync(
                     **_pause_kwargs
                 )
             )
-
             # TODO: for async version -> `.pause_from_aio()`?
             # bg_task, _ = await fute
             bg_task, _ = greenback.await_(fute)
@@ -2699,7 +2701,8 @@ _crash_msg: str = (
 
 
 def _post_mortem(
-    repl: PdbREPL,  # normally passed by `_pause()`
+    # provided and passed by `_pause()`
+    repl: PdbREPL,
 
     # XXX all `partial`-ed in by `post_mortem()` below!
     tb: TracebackType,
@@ -3016,17 +3019,7 @@ def open_crash_handler(
         yield
     except tuple(catch) as err:
         if type(err) not in ignore:
-
-            # use our re-impl-ed version
-            _post_mortem(
-                repl=mk_pdb(),
-                tb=sys.exc_info()[2],
-                api_frame=inspect.currentframe().f_back,
-            )
-
-            # XXX NOTE, `pdbp`'s version seems to lose the up-stack
-            # tb-info?
-            # pdbp.xpm()
+            pdbp.xpm()
 
         raise