Bah! just refine `devx.pformat.nest_from_op()`now!

Since we're gonna prolly start using it for serious..
- drop `back_from_op`.
- rename `tree_str` -> `text`
- move the huge comment-doc for "sclang" into the fn body.
- change all usage to reflect.

examples/debugging/root_cancelled_but_child_is_in_tty_lock.py

@@ -24,10 +24,9 @@ async def spawn_until(depth=0):
 
 
 async def main():
-    """The main ``tractor`` routine.
-
-    The process tree should look as approximately as follows when the debugger
-    first engages:
+    '''
+    The process tree should look as approximately as follows when the
+    debugger first engages:
 
     python examples/debugging/multi_nested_subactors_bp_forever.py
     ├─ python -m tractor._child --uid ('spawner1', '7eab8462 ...)
@@ -37,10 +36,11 @@ async def main():
     └─ python -m tractor._child --uid ('spawner0', '1d42012b ...)
        └─ python -m tractor._child --uid ('name_error', '6c2733b8 ...)
 
-    """
+    '''
     async with tractor.open_nursery(
         debug_mode=True,
-        loglevel='warning'
+        loglevel='devx',
+        enable_transports=['uds'],
     ) as n:
 
         # spawn both actors

examples/debugging/shield_hang_in_sub.py

@@ -37,6 +37,7 @@ async def main(
             enable_stack_on_sig=True,
             # maybe_enable_greenback=False,
             loglevel='devx',
+            enable_transports=['uds'],
         ) as an,
     ):
         ptl: tractor.Portal  = await an.start_actor(

examples/debugging/subactor_bp_in_ctx.py

@@ -33,8 +33,11 @@ async def just_bp(
 
 
 async def main():
+
     async with tractor.open_nursery(
         debug_mode=True,
+        enable_transports=['uds'],
+        loglevel='devx',
     ) as n:
         p = await n.start_actor(
             'bp_boi',

tests/devx/test_debugger.py

@@ -10,10 +10,14 @@ TODO:
     - wonder if any of it'll work on OS X?
 
 """
+from __future__ import annotations
 from functools import partial
 import itertools
 import platform
 import time
+from typing import (
+    TYPE_CHECKING,
+)
 
 import pytest
 from pexpect.exceptions import (
@@ -34,6 +38,9 @@ from .conftest import (
     assert_before,
 )
 
+if TYPE_CHECKING:
+    from ..conftest import PexpectSpawner
+
 # TODO: The next great debugger audit could be done by you!
 # - recurrent entry to breakpoint() from single actor *after* and an
 #   error in another task?
@@ -1062,6 +1069,88 @@ def test_shield_pause(
     child.expect(EOF)
 
 
+@pytest.mark.parametrize(
+    'quit_early', [False, True]
+)
+def test_ctxep_pauses_n_maybe_ipc_breaks(
+    spawn: PexpectSpawner,
+    quit_early: bool,
+):
+    '''
+    Audit generator embedded `.pause()`es from within a `@context`
+    endpoint with a chan close at the end, requiring that ctl-c is
+    mashed and zombie reaper kills sub with no hangs.
+
+    '''
+    child = spawn('subactor_bp_in_ctx')
+    child.expect(PROMPT)
+
+    # 3 iters for the `gen()` pause-points
+    for i in range(3):
+        assert_before(
+            child,
+            [
+                _pause_msg,
+                "('bp_boi'",  # actor name
+                "<Task 'just_bp'",  # task name
+            ]
+        )
+        if (
+            i == 1
+            and
+            quit_early
+        ):
+            child.sendline('q')
+            child.expect(PROMPT)
+            assert_before(
+                child,
+                ["tractor._exceptions.RemoteActorError: remote task raised a 'BdbQuit'",
+                 "bdb.BdbQuit",
+                 "('bp_boi'",
+                ]
+            )
+            child.sendline('c')
+            child.expect(EOF)
+            assert_before(
+                child,
+                ["tractor._exceptions.RemoteActorError: remote task raised a 'BdbQuit'",
+                 "bdb.BdbQuit",
+                 "('bp_boi'",
+                ]
+            )
+            break  # end-of-test
+
+        child.sendline('c')
+        try:
+            child.expect(PROMPT)
+        except TIMEOUT:
+            # no prompt since we hang due to IPC chan purposely
+            # closed so verify we see error reporting as well as
+            # a failed crash-REPL request msg and can CTL-c our way
+            # out.
+            assert_before(
+                child,
+                ['peer IPC channel closed abruptly?',
+                 'another task closed this fd',
+                 'Debug lock request was CANCELLED?',
+                 "TransportClosed: 'MsgpackUDSStream' was already closed locally ?",]
+
+                # XXX races on whether these show/hit?
+                 # 'Failed to REPl via `_pause()` You called `tractor.pause()` from an already cancelled scope!',
+                 # 'AssertionError',
+            )
+            # OSc(ancel) the hanging tree
+            do_ctlc(
+                child=child,
+                expect_prompt=False,
+            )
+            child.expect(EOF)
+            assert_before(
+                child,
+                ['KeyboardInterrupt'],
+            )
+
+
 # TODO: better error for "non-ideal" usage from the root actor.
 # -[ ] if called from an async scope emit a message that suggests
 #    using `await tractor.pause()` instead since it's less overhead

tractor/_entry.py

@@ -135,12 +135,12 @@ def _trio_main(
             f'  loglevel: {actor.loglevel}\n'
         )
         log.info(
-            'Starting new `trio` subactor:\n'
+            'Starting new `trio` subactor\n'
             +
             pformat.nest_from_op(
                 input_op='>(',  # see syntax ideas above
-                tree_str=actor_info,
-                back_from_op=2,  # since "complete"
+                text=actor_info,
+                nest_indent=2,  # since "complete"
             )
         )
     logmeth = log.info
@@ -149,8 +149,8 @@ def _trio_main(
         +
         pformat.nest_from_op(
             input_op=')>',  # like a "closed-to-play"-icon from super perspective
-            tree_str=actor_info,
-            back_from_op=1,
+            text=actor_info,
+            nest_indent=1,
         )
     )
     try:
@@ -167,7 +167,7 @@ def _trio_main(
             +
             pformat.nest_from_op(
                 input_op='c)>',  # closed due to cancel (see above)
-                tree_str=actor_info,
+                text=actor_info,
             )
         )
     except BaseException as err:
@@ -177,7 +177,7 @@ def _trio_main(
             +
             pformat.nest_from_op(
                 input_op='x)>',  # closed by error
-                tree_str=actor_info,
+                text=actor_info,
             )
         )
         # NOTE since we raise a tb will already be shown on the

tractor/_root.py

@@ -521,7 +521,7 @@ async def open_root_actor(
 
                     op_nested_actor_repr: str = _pformat.nest_from_op(
                         input_op='>) ',
-                        tree_str=actor.pformat(),
+                        text=actor.pformat(),
                         nest_prefix='|_',
                     )
                     logger.info(

tractor/_rpc.py

@@ -255,7 +255,7 @@ async def _errors_relayed_via_ipc(
     ctx: Context,
     is_rpc: bool,
 
-    hide_tb: bool = False,
+    hide_tb: bool = True,
     debug_kbis: bool = False,
     task_status: TaskStatus[
         Context | BaseException
@@ -380,9 +380,9 @@ async def _errors_relayed_via_ipc(
     # they can be individually ccancelled.
     finally:
 
-        # if the error is not from user code and instead a failure
-        # of a runtime RPC or transport failure we do prolly want to
-        # show this frame
+        # if the error is not from user code and instead a failure of
+        # an internal-runtime-RPC or IPC-connection, we do (prolly) want
+        # to show this frame!
         if (
             rpc_err
             and (

tractor/_runtime.py

@@ -1698,10 +1698,10 @@ async def async_main(
         )
 
     op_nested_actor_repr: str = _pformat.nest_from_op(
-        input_op=')> ',
-        tree_str=actor.pformat(),
+        input_op=')>',
+        text=actor.pformat(),
         nest_prefix='|_',
-        back_from_op=2,
+        nest_indent=1,  # under >
     )
     teardown_report += (
         'Actor runtime exited\n'

tractor/_supervise.py

@@ -593,9 +593,10 @@ async def _open_and_supervise_one_cancels_all_nursery(
     # final exit
 
 
-@acm
 # @api_frame
+@acm
 async def open_nursery(
+    *,  # named params only!
     hide_tb: bool = True,
     **kwargs,
     # ^TODO, paramspec for `open_root_actor()`

tractor/devx/pformat.py

@@ -249,14 +249,29 @@ def pformat_cs(
     )
 
 
-# TODO: move this func to some kinda `.devx.pformat.py` eventually
-# as we work out our multi-domain state-flow-syntax!
 def nest_from_op(
-    input_op: str,
+    input_op: str,  # TODO, Literal of all op-"symbols" from below?
+    text: str,  # TODO? better name, like `text`?
+
+    nest_prefix: str = '|_',
+    nest_indent: int = 0,
+    # XXX indent `next_prefix` "to-the-right-of" `input_op`
+    # by this count of whitespaces (' ').
+
+) -> str:
+    '''
+    Depth-increment the input (presumably hierarchy/supervision)
+    input "tree string" below the provided `input_op` execution
+    operator, so injecting a `"\n|_{input_op}\n"`and indenting the
+    `tree_str` to nest content aligned with the ops last char.
+
+    '''
+    # `sclang` "structurred-concurrency-language": an ascii-encoded
+    # symbolic alphabet to describe concurrent systems.
     #
-    # ?TODO? an idea for a syntax to the state of concurrent systems
-    # as a "3-domain" (execution, scope, storage) model and using
-    # a minimal ascii/utf-8 operator-set.
+    # ?TODO? aa more fomal idea for a syntax to the state of
+    # concurrent systems as a "3-domain" (execution, scope, storage)
+    # model and using a minimal ascii/utf-8 operator-set.
     #
     # try not to take any of this seriously yet XD
     #
@@ -322,37 +337,29 @@ def nest_from_op(
     #
     # =>{  recv-req to open
     # <={  send-status that it closed
+    #
+    if (
+        nest_prefix
+        and
+        nest_indent
+    ):
+        nest_prefix: str = textwrap.indent(
+            nest_prefix,
+            prefix=nest_indent*' ',
+        )
 
-    tree_str: str,
-
-    # NOTE: so move back-from-the-left of the `input_op` by
-    # this amount.
-    back_from_op: int = 0,
-    nest_prefix: str = ''
-
-) -> str:
-    '''
-    Depth-increment the input (presumably hierarchy/supervision)
-    input "tree string" below the provided `input_op` execution
-    operator, so injecting a `"\n|_{input_op}\n"`and indenting the
-    `tree_str` to nest content aligned with the ops last char.
-
-    '''
+    tree_str_indent: int = len(nest_prefix)
     indented_tree_str: str = textwrap.indent(
-        tree_str,
-        prefix=' ' *(
-            len(input_op)
-            -
-            (back_from_op + 1)
-        ),
+        text,
+        prefix=' '*tree_str_indent
     )
     # inject any provided nesting-prefix chars
     # into the head of the first line.
     if nest_prefix:
         indented_tree_str: str = (
-            f'{nest_prefix}'
-            f'{indented_tree_str[len(nest_prefix):]}'
+            f'{nest_prefix}{indented_tree_str[tree_str_indent:]}'
         )
+
     return (
         f'{input_op}\n'
         f'{indented_tree_str}'