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tractor/tractor/trionics/_taskc.py

72 lines
2.1 KiB
Python

# tractor: structured concurrent "actors".
# Copyright 2018-eternity Tyler Goodlet.
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
'''
`trio.Task` cancellation helpers, extensions and "holsters".
'''
from __future__ import annotations
from contextlib import (
asynccontextmanager as acm,
)
import trio
# from trio import TaskStatus
@acm
async def maybe_raise_from_masking_exc(
tn: trio.Nursery,
unmask_from: BaseException|None = trio.Cancelled
# TODO, maybe offer a collection?
# unmask_from: set[BaseException] = {
# trio.Cancelled,
# },
):
if not unmask_from:
yield
return
try:
yield
except* unmask_from as be_eg:
# TODO, if we offer `unmask_from: set`
# for masker_exc_type in unmask_from:
matches, rest = be_eg.split(unmask_from)
if not matches:
raise
for exc_match in be_eg.exceptions:
if (
(exc_ctx := exc_match.__context__)
and
type(exc_ctx) not in {
# trio.Cancelled, # always by default?
unmask_from,
}
):
exc_ctx.add_note(
f'\n'
f'WARNING: the above error was masked by a {unmask_from!r} !?!\n'
f'Are you always cancelling? Say from a `finally:` ?\n\n'
f'{tn!r}'
)
raise exc_ctx from exc_match