Update `sync_bp` + tighten `test_pause_from_sync`

Add `disable_pdbp_color()` to the `sync_bp` example
to suppress pygments prompt coloring when
`PYTHON_COLORS=0` — makes pexpect pattern matching
deterministic.

Deats,
- set `loglevel='pdb'` in both script + test spawn.
- disable `enable_stack_on_sig` in example, assert
  no `stackscope` output in test.
- update `attach_patts` keys/values with `|_<Task`
  / `|_<Thread` / `|_('subactor'` prefixes to match
  actual tree-dump format.
- add call-site patterns (`tractor.pause_from_sync()`
  `tractor.pause()`, `breakpoint(hide_tb=...)`).
- trim trailing `\n` from `Lock.repr()` output.

(this commit msg was generated in some part by [`claude-code`][claude-code-gh])
[claude-code-gh]: https://github.com/anthropics/claude-code

examples/debugging/sync_bp.py

@@ -1,9 +1,22 @@
 from functools import partial
+import os
 import time
 
+# ?TODO? how to make `pdbp` enforce this?
+# os.environ['PYTHON_COLORS'] = '0'
+# os.environ['NO_COLOR'] = '1'
+
 import trio
 import tractor
 
+# disable `pbdp` prompt colors
+# for prompt matching in test.
+def disable_pdbp_color():
+    if os.environ['PYTHON_COLORS'] == '0':
+        from tractor.devx.debug import _repl
+        _repl.TractorConfig.use_pygments = False
+
+
 # TODO: only import these when not running from test harness?
 # can we detect `pexpect` usage maybe?
 # from tractor.devx.debug import (
@@ -42,6 +55,7 @@ async def start_n_sync_pause(
     ctx: tractor.Context,
 ):
     actor: tractor.Actor = tractor.current_actor()
+    disable_pdbp_color()
 
     # sync to parent-side task
     await ctx.started()
@@ -52,13 +66,15 @@ async def start_n_sync_pause(
 
 
 async def main() -> None:
+    disable_pdbp_color()
     async with (
         tractor.open_nursery(
             debug_mode=True,
             maybe_enable_greenback=True,
-            enable_stack_on_sig=True,
-            # loglevel='warning',
-            # loglevel='devx',
+
+            # XXX flags required for test pattern matching.
+            loglevel='pdb',
+            # enable_stack_on_sig=True,
         ) as an,
         trio.open_nursery() as tn,
     ):
@@ -68,8 +84,8 @@ async def main() -> None:
         p: tractor.Portal  = await an.start_actor(
             'subactor',
             enable_modules=[__name__],
-            # infect_asyncio=True,
             debug_mode=True,
+            # infect_asyncio=True,
         )
 
         # TODO: 3 sub-actor usage cases:

tests/devx/conftest.py

@@ -95,6 +95,8 @@ def spawn(
         os.environ['PYTHON_COLORS'] = '0'
         # disable all ANSI color output
         # os.environ['NO_COLOR'] = '1'
+        # ?TODO, doesn't seem to disable prompt color
+        # for `pdbp`?
 
     def set_spawn_method(
         start_method: str,

tests/devx/test_pause_from_non_trio.py

@@ -66,19 +66,28 @@ def test_pause_from_sync(
     # XXX required for `breakpoint()` overload and
     # thus`tractor.devx.pause_from_sync()`.
     pytest.importorskip('greenback')
-    child = spawn('sync_bp')
+    child = spawn(
+        'sync_bp',
+        loglevel='pdb',  # XXX pattern matching
+    )
 
     # first `sync_pause()` after nurseries open
     child.expect(PROMPT)
-    assert_before(
+    _before: str = assert_before(
         child,
         [
-            # pre-prompt line
-            _pause_msg,
-            "<Task '__main__.main'",
+            # devx-loglevel
+            # "imported <module 'greenback' from",
+            # "successfully scheduled `._pause()` in `trio` thread on behalf of <Task",
+
+            _pause_msg,  # pre-prompt line
             "('root'",
+            "<Task '__main__.main'",
+            "tractor.pause_from_sync()",
         ]
     )
+    # XXX `enable_stack_on_sig=False` in script
+    assert 'stackscope' not in _before
     if ctlc:
         do_ctlc(child)
         # ^NOTE^ subactor not spawned yet; don't need extra delay.
@@ -88,18 +97,18 @@ def test_pause_from_sync(
     # first `await tractor.pause()` inside `p.open_context()` body
     child.expect(PROMPT)
 
-    # XXX shouldn't see gb loaded message with PDB loglevel!
-    # assert not in_prompt_msg(
-    #     child,
-    #     ['`greenback` portal opened!'],
-    # )
     # should be same root task
     assert_before(
         child,
         [
+            # XXX should see gb loaded with devx-loglevel.
+            # "`greenback` portal opened!",
+            # "Activated `greenback` for `tractor.pause_from_sync()` support!",
+
             _pause_msg,
-            "<Task '__main__.main'",
             "('root'",
+            "<Task '__main__.main'",
+            "tractor.pause()",
         ]
     )
 
@@ -130,17 +139,17 @@ def test_pause_from_sync(
     # `Lock.acquire()`-ed
     # (NOT both, which will result in REPL clobbering!)
     attach_patts: dict[str, list[str]] = {
-        'subactor': [
-            "'start_n_sync_pause'",
-            "('subactor'",
+        "|_<Task 'start_n_sync_pause'": [
+            "|_('subactor'",
+            "tractor.pause_from_sync()",
         ],
-        'inline_root_bg_thread': [
-            "<Thread(inline_root_bg_thread",
+        "|_<Thread(inline_root_bg_thread": [
             "('root'",
+            "breakpoint(hide_tb=hide_tb)",
         ],
-        'start_soon_root_bg_thread': [
-            "<Thread(start_soon_root_bg_thread",
-            "('root'",
+        "|_<Thread(start_soon_root_bg_thread": [
+            "|_('root'",
+            "tractor.pause_from_sync()",
         ],
     }
     conts: int = 0  # for debugging below matching logic on failure

tractor/devx/debug/_tty_lock.py

@@ -181,7 +181,7 @@ class Lock:
         return (
             f'<{cls.__name__}(\n'
             f'{body}'
-            ')>\n\n'
+            ')>\n'
         )
 
     @classmethod
@@ -282,7 +282,7 @@ class Lock:
             ):
                 message += (
                     '-> No new task holds the TTY lock!\n\n'
-                    f'{Lock.repr()}\n'
+                    f'{Lock.repr()}'
                 )
 
             elif (