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Make `@context`-cancelled tests more pedantic 

In order to match a very significant and coming-soon patch set to the
IPC `Context` and `Channel` cancellation semantics with significant but
subtle changes to the primitives and runtime logic:

- a new set of `Context` state pub meth APIs for checking exact
  inter-actor-linked-task outcomes such as `.outcome`, `.maybe_error`,
  and `.cancel_acked`.

- trying to move away from `Context.cancelled_caught` usage since the
  semantics from `trio` don't really map well (in terms of cancel
  requests and how they result in cancel-scope graceful closure) and
  `.cancel_acked: bool` is a better approach for IPC req-resp msging.
  - change test usage to access `._scope.cancelled_caught` directly.

- more pedantic ctxc-raising expects around the "type of self
  cancellation" and final outcome in ctxc cases:
  - `ContextCancelled` is raised by ctx (`Context.result()`) consumer
    methods when `Portal.cancel_actor()` is called (since it's an
    out-of-band request) despite `Channel._cancel_called` being set.
  - also raised by `.open_context().__aexit__()` on close.
  - `.outcome` is always `.maybe_error` is always one of
    `._local/remote_error`.
shielded_ctx_cancel
Tyler Goodlet 2024-02-28 17:13:01 -05:00
parent c6ee4e5dc1
commit d08aeaeafe
2 changed files with 106 additions and 23 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
tests/test_cancellation.py
View File

@ -48,11 +48,13 @@ async def do_nuthin():
ids=['no_args', 'unexpected_args'],
)
def test_remote_error(reg_addr, args_err):
"""Verify an error raised in a subactor that is propagated
'''
Verify an error raised in a subactor that is propagated
to the parent nursery, contains the underlying boxed builtin
error type info and causes cancellation and reraising all the
way up the stack.
"""
'''
args, errtype = args_err
async def main():
@ -65,7 +67,9 @@ def test_remote_error(reg_addr, args_err):
# an exception group outside the nursery since the error
# here and the far end task error are one in the same?
portal = await nursery.run_in_actor(
assert_err, name='errorer', **args
assert_err,
name='errorer',
**args
)
# get result(s) from main task

119
tests/test_context_stream_semantics.py
View File

@ -5,7 +5,7 @@ Verify the we raise errors when streams are opened prior to
sync-opening a ``tractor.Context`` beforehand.
'''
# from contextlib import asynccontextmanager as acm
from contextlib import asynccontextmanager as acm
from itertools import count
import platform
from pprint import pformat
@ -250,6 +250,17 @@ def test_simple_context(
trio.run(main)
@acm
async def expect_ctxc(yay: bool) -> None:
if yay:
try:
yield
except ContextCancelled:
return
else:
yield
@pytest.mark.parametrize(
'callee_returns_early',
[True, False],
@ -280,23 +291,60 @@ def test_caller_cancels(
async def check_canceller(
ctx: Context,
) -> None:
# should not raise yet return the remote
# context cancelled error.
res = await ctx.result()
actor: Actor = current_actor()
uid: tuple = actor.uid
if (
cancel_method == 'portal'
and not callee_returns_early
):
try:
res = await ctx.result()
assert 0, 'Portal cancel should raise!'
except ContextCancelled as ctxc:
assert ctx.chan._cancel_called
assert ctxc.canceller == uid
assert ctxc is ctx.maybe_error
# NOTE: should not ever raise even in the `ctx`
# case since self-cancellation should swallow the ctxc
# silently!
else:
res = await ctx.result()
# we actually get a result
if callee_returns_early:
assert res == 'yo'
assert ctx.outcome is res
assert ctx.maybe_error is None
else:
err = res
err: Exception = ctx.outcome
assert isinstance(err, ContextCancelled)
assert (
tuple(err.canceller)
==
current_actor().uid
uid
)
assert (
err
is ctx.maybe_error
is ctx._remote_error
)
if le := ctx._local_error:
assert err is le
# else:
# TODO: what should this be then?
# not defined until block closes right?
#
# await tractor.pause()
# assert ctx._local_error is None
async def main():
async with tractor.open_nursery(
debug_mode=debug_mode,
) as an:
@ -306,11 +354,16 @@ def test_caller_cancels(
)
timeout = 0.5 if not callee_returns_early else 2
with trio.fail_after(timeout):
async with portal.open_context(
simple_setup_teardown,
data=10,
block_forever=not callee_returns_early,
) as (ctx, sent):
async with (
expect_ctxc(yay=cancel_method == 'portal'),
portal.open_context(
simple_setup_teardown,
data=10,
block_forever=not callee_returns_early,
) as (ctx, sent),
):
if callee_returns_early:
# ensure we block long enough before sending
@ -332,6 +385,16 @@ def test_caller_cancels(
if cancel_method != 'portal':
await portal.cancel_actor()
# since the `.cancel_actor()` call just above
# will cause the `.open_context().__aexit__()` raise
# a ctxc which should in turn cause `ctx._scope` to
# catch any cancellation?
if (
not callee_returns_early
and cancel_method == 'portal'
):
assert ctx._scope.cancelled_caught
trio.run(main)
@ -434,7 +497,6 @@ async def test_callee_closes_ctx_after_stream_open(
@tractor.context
async def expect_cancelled(
ctx: Context,
) -> None:
@ -454,7 +516,7 @@ async def expect_cancelled(
raise
else:
assert 0, "Wasn't cancelled!?"
assert 0, "callee wasn't cancelled !?"
@pytest.mark.parametrize(
@ -473,8 +535,8 @@ async def test_caller_closes_ctx_after_callee_opens_stream(
async with tractor.open_nursery(
debug_mode=debug_mode,
) as an:
root: Actor = current_actor()
root: Actor = current_actor()
portal = await an.start_actor(
'ctx_cancelled',
enable_modules=[__name__],
@ -487,11 +549,13 @@ async def test_caller_closes_ctx_after_callee_opens_stream(
await portal.run(assert_state, value=True)
# call cancel explicitly
# call `ctx.cancel()` explicitly
if use_ctx_cancel_method:
await ctx.cancel()
# NOTE: means the local side `ctx._scope` will
# have been cancelled by an ctxc ack and thus
# `._scope.cancelled_caught` should be set.
try:
async with ctx.open_stream() as stream:
async for msg in stream:
@ -520,20 +584,35 @@ async def test_caller_closes_ctx_after_callee_opens_stream(
assert portal.channel.connected()
# ctx is closed here
await portal.run(assert_state, value=False)
await portal.run(
assert_state,
value=False,
)
else:
try:
with trio.fail_after(0.2):
await ctx.result()
assert 0, "Callee should have blocked!?"
except trio.TooSlowError:
# NO-OP -> since already called above
await ctx.cancel()
# local scope should have absorbed the cancellation
assert ctx.cancelled_caught
assert ctx._remote_error is ctx._local_error
# NOTE: local scope should have absorbed the cancellation since
# in this case we call `ctx.cancel()` and the local
# `._scope` gets `.cancel_called` on the ctxc ack.
if use_ctx_cancel_method:
assert ctx._scope.cancelled_caught
# rxed ctxc response from far end
assert ctx.cancel_acked
assert (
ctx._remote_error
is ctx._local_error
is ctx.maybe_error
is ctx.outcome
)
try:
async with ctx.open_stream() as stream: