First draft workin minus non-main-thread usage!

examples/debugging/sync_bp.py

@@ -0,0 +1,69 @@
+import trio
+import tractor
+
+
+def sync_pause():
+    tractor.pause_from_sync()
+
+
+@tractor.context
+async def start_n_sync_pause(
+    ctx: tractor.Context,
+):
+    # sync to requesting peer
+    await ctx.started()
+
+    actor: tractor.Actor = tractor.current_actor()
+    print(f'entering SYNC PAUSE in {actor.uid}')
+    sync_pause()
+    print(f'back from SYNC PAUSE in {actor.uid}')
+
+
+async def main() -> None:
+
+    from tractor._rpc import maybe_import_gb
+
+    async with tractor.open_nursery(
+        debug_mode=True,
+    ) as an:
+
+        # TODO: where to put this?
+        # => just inside `open_root_actor()` yah?
+        await maybe_import_gb()
+
+        p: tractor.Portal  = await an.start_actor(
+            'subactor',
+            enable_modules=[__name__],
+            # infect_asyncio=True,
+            debug_mode=True,
+            loglevel='cancel',
+        )
+
+        # TODO: 3 sub-actor usage cases:
+        # -[ ] via a `.run_in_actor()` call
+        # -[ ] via a `.run()`
+        # -[ ] via a `.open_context()`
+        #
+        async with p.open_context(
+            start_n_sync_pause,
+        ) as (ctx, first):
+            assert first is None
+
+            await tractor.pause()
+            sync_pause()
+
+        # TODO: make this work!!
+        await trio.to_thread.run_sync(
+            sync_pause,
+            abandon_on_cancel=False,
+        )
+
+        await ctx.cancel()
+
+        # TODO: case where we cancel from trio-side while asyncio task
+        # has debugger lock?
+        await p.cancel_actor()
+
+
+if __name__ == '__main__':
+    trio.run(main)

tractor/devx/_debug.py

@@ -46,7 +46,7 @@ import pdbp
 import tractor
 import trio
 from trio.lowlevel import current_task
-from trio_typing import (
+from trio import (
     TaskStatus,
     # Task,
 )
@@ -400,7 +400,6 @@ async def wait_for_parent_stdin_hijack(
 
                 # this syncs to child's ``Context.started()`` call.
                 async with portal.open_context(
-
                     lock_tty_for_child,
                     subactor_uid=actor_uid,
 
@@ -682,7 +681,10 @@ def _set_trace(
 async def _pause(
 
     debug_func: Callable = _set_trace,
-    release_lock_signal: trio.Event | None = None,
+
+    # NOTE: must be passed in the `.pause_from_sync()` case!
+    pdb: MultiActorPdb|None = None,
+    undo_sigint: Callable|None = None,
 
     # TODO: allow caller to pause despite task cancellation,
     # exactly the same as wrapping with:
@@ -691,8 +693,7 @@ async def _pause(
     # => the REMAINING ISSUE is that the scope's .__exit__() frame
     # is always show in the debugger on entry.. and there seems to
     # be no way to override it?..
-    # shield: bool = False,
+    #
-
     shield: bool = False,
     task_status: TaskStatus[trio.Event] = trio.TASK_STATUS_IGNORED
 
@@ -707,7 +708,6 @@ async def _pause(
     '''
     __tracebackhide__: bool = True
     actor = current_actor()
-    pdb, undo_sigint = mk_mpdb()
     task_name: str = trio.lowlevel.current_task().name
 
     if (
@@ -716,10 +716,15 @@ async def _pause(
     ):
         Lock.local_pdb_complete = trio.Event()
 
+    if debug_func is not None:
         debug_func = partial(
             debug_func,
         )
 
+    if pdb is None:
+        assert undo_sigint is None, 'You must pass both!?!'
+        pdb, undo_sigint = mk_mpdb()
+
     # TODO: need a more robust check for the "root" actor
     if (
         not is_root_process()
@@ -761,12 +766,14 @@ async def _pause(
         # ```
         # but not entirely sure if that's a sane way to implement it?
         try:
+            print("ACQUIRING TTY LOCK from CHILD")
             with trio.CancelScope(shield=True):
                 await actor._service_n.start(
                     wait_for_parent_stdin_hijack,
                     actor.uid,
                 )
                 Lock.repl = pdb
+
         except RuntimeError:
             Lock.release()
 
@@ -779,11 +786,13 @@ async def _pause(
             raise
 
     elif is_root_process():
+        print("ROOT TTY LOCK BRANCH")
 
         # we also wait in the root-parent for any child that
         # may have the tty locked prior
         # TODO: wait, what about multiple root tasks acquiring it though?
         if Lock.global_actor_in_debug == actor.uid:
+            print("ROOT ALREADY HAS TTY?")
             # re-entrant root process already has it: noop.
             return
 
@@ -797,11 +806,14 @@ async def _pause(
 
             # must shield here to avoid hitting a ``Cancelled`` and
             # a child getting stuck bc we clobbered the tty
+            print("ACQUIRING TTY LOCK from ROOT")
             with trio.CancelScope(shield=True):
                 await Lock._debug_lock.acquire()
         else:
             # may be cancelled
+            print("ROOT TRYING LOCK ACQUIRE")
             await Lock._debug_lock.acquire()
+            print("ROOT LOCKED TTY")
 
         Lock.global_actor_in_debug = actor.uid
         Lock.local_task_in_debug = task_name
@@ -811,16 +823,11 @@ async def _pause(
         # TODO: do we want to support using this **just** for the
         # locking / common code (prolly to help address #320)?
         #
-        # if debug_func is None:
+        if debug_func is None:
-            # assert release_lock_signal, (
+            task_status.started(Lock)
-            #     'Must pass `release_lock_signal: trio.Event` if no '
+            print("ROOT .started(Lock) now!")
-            #     'trace func provided!'
-            # )
-            # print(f"{actor.uid} ENTERING WAIT")
-            # with trio.CancelScope(shield=True):
-            #     await release_lock_signal.wait()
 
-        # else:
+        else:
             # block here one (at the appropriate frame *up*) where
             # ``breakpoint()`` was awaited and begin handling stdio.
             log.debug('Entering sync world of the `pdb` REPL..')
@@ -862,8 +869,7 @@ async def _pause(
 
 async def pause(
 
-    debug_func: Callable = _set_trace,
+    debug_func: Callable|None = _set_trace,
-    release_lock_signal: trio.Event | None = None,
 
     # TODO: allow caller to pause despite task cancellation,
     # exactly the same as wrapping with:
@@ -872,10 +878,11 @@ async def pause(
     # => the REMAINING ISSUE is that the scope's .__exit__() frame
     # is always show in the debugger on entry.. and there seems to
     # be no way to override it?..
-    # shield: bool = False,
+    #
-
     shield: bool = False,
-    task_status: TaskStatus[trio.Event] = trio.TASK_STATUS_IGNORED
+    task_status: TaskStatus[trio.Event] = trio.TASK_STATUS_IGNORED,
+
+    **_pause_kwargs,
 
 ) -> None:
     '''
@@ -920,16 +927,16 @@ async def pause(
             task_status.started(cs)
             return await _pause(
                 debug_func=debug_func,
-                release_lock_signal=release_lock_signal,
                 shield=True,
                 task_status=task_status,
+                **_pause_kwargs
             )
     else:
         return await _pause(
             debug_func=debug_func,
-            release_lock_signal=release_lock_signal,
             shield=False,
             task_status=task_status,
+            **_pause_kwargs
         )
 
 
@@ -938,46 +945,64 @@ async def pause(
 # TODO: allow pausing from sync code.
 # normally by remapping python's builtin breakpoint() hook to this
 # runtime aware version which takes care of all .
-def pause_from_sync() -> None:
+def pause_from_sync(
-    print("ENTER SYNC PAUSE")
+    hide_tb: bool = True
+) -> None:
+
+    __tracebackhide__: bool = hide_tb
     actor: tractor.Actor = current_actor(
         err_on_no_runtime=False,
     )
-    if actor:
+    print(
+        f'{actor.uid}: JUST ENTERED `tractor.pause_from_sync()`'
+        f'|_{actor}\n'
+    )
+    if not actor:
+        raise RuntimeError(
+            'Not inside the `tractor`-runtime?\n'
+            '`tractor.pause_from_sync()` is not functional without a wrapping\n'
+            '- `async with tractor.open_nursery()` or,\n'
+            '- `async with tractor.open_root_actor()`\n'
+        )
+
     try:
         import greenback
-            # __tracebackhide__ = True
+    except ModuleNotFoundError:
+        raise RuntimeError(
+            'The `greenback` lib is required to use `tractor.pause_from_sync()`!\n'
+            'https://github.com/oremanj/greenback\n'
+        )
 
-
+    # out = greenback.await_(
-            # task_can_release_tty_lock = trio.Event()
+    #     actor._service_n.start(partial(
+    #         pause,
+    #         debug_func=None,
+    #         release_lock_signal=task_can_release_tty_lock,
+    #     ))
+    # )
 
     # spawn bg task which will lock out the TTY, we poll
     # just below until the release event is reporting that task as
     # waiting.. not the most ideal but works for now ;)
+    db, undo_sigint = mk_mpdb()
     greenback.await_(
-                actor._service_n.start(partial(
+        pause(
-                    pause,
             debug_func=None,
-                    # release_lock_signal=task_can_release_tty_lock,
+            pdb=db,
-                ))
+            undo_sigint=undo_sigint,
+        )
     )
 
-        except ModuleNotFoundError:
-            log.warning('NO GREENBACK FOUND')
-    else:
-        log.warning('Not inside actor-runtime')
-
-    db, undo_sigint = mk_mpdb()
     Lock.local_task_in_debug = 'sync'
-    # db.config.enable_hidden_frames = True
 
-    # we entered the global ``breakpoint()`` built-in from sync
+    # TODO: ensure we aggressively make the user aware about
+    # entering the global ``breakpoint()`` built-in from sync
     # code?
     frame: FrameType | None = sys._getframe()
-    # print(f'FRAME: {str(frame)}')
-    # assert not db._is_hidden(frame)
-
     frame: FrameType = frame.f_back  # type: ignore
+
+    # db.config.enable_hidden_frames = True
+    # assert not db._is_hidden(frame)
     # print(f'FRAME: {str(frame)}')
     # if not db._is_hidden(frame):
     #     pdbp.set_trace()
@@ -985,17 +1010,21 @@ def pause_from_sync() -> None:
     #     (frame, frame.f_lineno)
     # )
     db.set_trace(frame=frame)
-    # NOTE XXX: see the `@pdbp.hideframe` decoration
+
-    # on `Lock.unshield_sigint()`.. I have NO CLUE why
+    # XXX NOTE XXX no other LOC can be here without it
+    # showing up in the REPL's last stack frame !?!
+    # -[ ] tried to use `@pdbp.hideframe` decoration but
+    #   still doesn't work
+    #
+    # FROM BEFORE: on `Lock.unshield_sigint()`.. I have NO CLUE why
     # the next instruction's def frame is being shown
     # in the tb but it seems to be something wonky with
     # the way `pdb` core works?
+    #
+    # NOTE: not needed any more anyway since it's all in
+    # `Lock.release()` now!
     # undo_sigint()
 
-    # Lock.global_actor_in_debug = actor.uid
-    # Lock.release()
-    # task_can_release_tty_lock.set()
-
 
 # using the "pause" semantics instead since
 # that better covers actually somewhat "pausing the runtime"