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dongarandClaude Opus 5.5 76d8e36f43
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nisse-dev: a VM lost as a helper's work is taken back ends the run
The property walk (seed 468, a CI run's moving seed) found it: when the
build VM went out of reach while _delegate moved the helper's work back
onto the milestone's branch, git's HostUnavailable came back as a
GitError, was noted as a fact, and the driver's run went on, calling the
model with its VM gone (no_model_on_a_lost_vm). Now a GitError caused by a
lost VM raises VMUnreachable once the delegation's intents are settled, so
the run ends and the VM is blocked, as for any other lost-VM call (#137).

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J5Utyfzw7gF7UhjRDEtjTk
2026-10-17 16:00:31 +00:00

380 lines
14 KiB
Python

"""A build VM out of reach (D3, #137): it blocks every project on it, the run
that finds it ends there, and it is tried again in the background; once it
answers, and still answers a settle period later, work goes on by itself. A
new host key is the operator's to trust (`vm ready`), and a VM the driver
found broken is never unblocked by a probe."""
from typing import Any
import pytest
from test_loop_milestones import DON, RESTATE, ScriptedModel, call, git, say
from test_loop_milestones import item as the_item
from test_loop_milestones import world as world # noqa: PLC0414 -- the fixture
from test_loop_toolchain import (
agent_for,
by_issue,
ready,
reimage,
said,
)
from test_loop_toolchain import project as project # noqa: PLC0414 -- the fixture
from nisse_core.execution.ssh import HostKeyChanged, HostUnavailable
from nisse_core.gitea import Issue
from nisse_core.log.canonical import ToolResult
from nisse_dev.loop.items import GO_AHEAD, READY, loop_of
RETRY, SETTLE = 300.0, 180.0
class Faults:
"""The build VM's SSH, broken on demand: ``down`` makes it unreachable,
``rekey`` makes it answer with a new host key, and ``drop_on`` takes it
down when a command containing that text runs. Probes are counted."""
def __init__(self, monkeypatch: pytest.MonkeyPatch, host: Any) -> None:
self.down = False
self.rekey = False
self.drop_on = ""
self.probes = 0
real = type(host).execute
faults = self
def execute(self: Any, command: str, **kw: Any) -> Any:
if faults.drop_on and faults.drop_on in command:
faults.down = True
if command == "true":
faults.probes += 1
if faults.rekey:
raise HostKeyChanged("the host key changed")
if faults.down:
raise HostUnavailable("ssh: connect to host: Connection timed out")
return real(self, command, **kw)
monkeypatch.setattr(type(host), "execute", execute)
class Clock:
def __init__(self) -> None:
self.now = 1000.0
def __call__(self) -> float:
return self.now
def blocks(world: dict[str, Any]) -> dict[str, str]:
return {h: b.cause for h, b in world["store"].vm_blocks().items()}
def test_an_unreachable_vm_blocks_and_goes_on_once_settled(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
world["forge"].issues.append(Issue(15, "Add count_lines", "count lines", "don", ()))
faults = Faults(monkeypatch, world["host"])
clock = Clock()
faults.down = True
agent, transport = agent_for(
world,
project,
ScriptedModel(ready(), RESTATE, RESTATE), # only once it's back
clock=clock,
vm_retry_s=RETRY,
vm_settle_s=SETTLE,
)
agent.intake()
assert list(blocks(world).values()) == ["unreachable"]
[told] = [m for m in transport.outbound if "I can't reach the build VM" in m.text]
assert told.thread is None
assert "try again every 5 minutes" in told.text
assert "answered for 3 minutes" in told.text
assert f"`vm ready {project}`" in told.text # if it's gone for good
assert "is out of reach" in agent.status()
assert loop_of(by_issue(world, 14)).wait == "" # not waiting on anyone
assert by_issue(world, 14).position == READY
# Tried again only when due, and quietly.
before = len(transport.outbound)
agent.intake() # the first round after it went: tried at once
clock.now += 60
agent.intake() # not due yet
assert faults.probes == 1
clock.now += RETRY
agent.intake()
assert faults.probes == 2
assert len(transport.outbound) == before
# Back: it answers, but work waits for it to settle.
faults.down = False
clock.now += RETRY
agent.intake()
assert blocks(world)
# Gone again while settling: the wait starts over.
faults.down = True
clock.now += SETTLE
agent.intake()
assert blocks(world)
faults.down = False
clock.now += RETRY
agent.intake() # answers
clock.now += SETTLE - 10
agent.intake() # not settled yet
assert blocks(world)
clock.now += 10
agent.intake() # settled: unblocked, and the work runs
assert blocks(world) == {}
assert [t for t in said(transport) if "is back" in t] == [
f"The build VM {world['host'].describe()} is back: {project} can go on."
]
assert loop_of(by_issue(world, 14)).wait == GO_AHEAD
assert loop_of(by_issue(world, 15)).wait == GO_AHEAD
def test_a_vm_lost_mid_run_ends_the_run_and_blocks(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
faults = Faults(monkeypatch, world["host"])
faults.drop_on = "GO-DOWN"
model = ScriptedModel(
ready(),
RESTATE,
[
call("start_milestone", name="m"),
call("run_command", command="echo GO-DOWN"),
call("run_command", command="echo never"),
],
# Nothing more: the model is never shown the failure.
)
agent, transport = agent_for(world, project, model, clock=Clock())
agent.intake()
say(transport, world, "go")
assert list(blocks(world).values()) == ["unreachable"]
item = the_item(world)
assert item.position == READY
results = [
e.event.result
for e in world["store"].transcript(item.id, "driver").read()
if isinstance(e.event, ToolResult)
]
assert results[-2].startswith("not finished: the build VM is unreachable")
assert results[-1] == "not run: the turn had ended"
assert not model.turns
def test_a_vm_lost_in_a_requested_step_ends_the_drivers_run(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
faults = Faults(monkeypatch, world["host"])
faults.drop_on = "GO-DOWN"
model = ScriptedModel(
ready(),
RESTATE,
[
call("start_milestone", name="m"),
call("toolchain_step", reason="it needs httpx"),
],
[call("run_command", command="pip install httpx # GO-DOWN")], # the step
)
agent, transport = agent_for(world, project, model, clock=Clock())
agent.intake()
say(transport, world, "go")
assert list(blocks(world).values()) == ["unreachable"]
assert the_item(world).position == READY
assert not model.turns # neither the step nor the driver went on
def test_a_vm_back_with_a_new_host_key_waits_for_the_operator(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
faults = Faults(monkeypatch, world["host"])
forgotten: list[str] = []
monkeypatch.setattr(
type(world["host"]), "forget_host_key", lambda self: forgotten.append("yes")
)
clock = Clock()
faults.down = True
agent, transport = agent_for(
world, project, ScriptedModel(ready(), RESTATE), clock=clock
)
agent.intake()
faults.down, faults.rekey = False, True
clock.now += RETRY
agent.intake()
assert list(blocks(world).values()) == ["host key"]
[asked] = [t for t in said(transport) if "different host key" in t]
assert f"`vm ready {project}`" in asked
clock.now += RETRY + SETTLE
agent.intake()
agent.intake()
assert blocks(world) # never cleared by a probe
faults.rekey = False
transport.receive(DON, f"vm ready {project}")
assert forgotten == ["yes"]
assert blocks(world) == {}
assert loop_of(the_item(world)).wait == GO_AHEAD
def test_the_operator_can_clear_an_unreachable_block(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
faults = Faults(monkeypatch, world["host"])
faults.down = True
agent, transport = agent_for(
world, project, ScriptedModel(ready(), RESTATE), clock=Clock()
)
agent.intake()
assert blocks(world)
faults.down = False
transport.receive(DON, "vm ready")
assert blocks(world) == {}
assert loop_of(the_item(world)).wait == GO_AHEAD
def test_a_broken_vm_is_never_unblocked_by_a_probe(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
faults = Faults(monkeypatch, world["host"])
clock = Clock()
agent, _ = agent_for(world, project, ScriptedModel(ready(), reimage()), clock=clock)
agent.intake()
for _ in range(3):
clock.now += RETRY + SETTLE
agent.intake()
assert list(blocks(world).values()) == ["broken"]
assert faults.probes == 0
def test_an_unreachable_block_survives_a_restart_and_is_tried_at_once(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
faults = Faults(monkeypatch, world["host"])
faults.down = True
clock = Clock()
agent, _ = agent_for(world, project, ScriptedModel(), clock=clock)
agent.intake()
agent.intake()
assert faults.probes == 1
again, _ = agent_for(world, project, ScriptedModel(), clock=clock)
again.boot()
again.intake() # a new process knows the block, not when it last tried
assert faults.probes == 2
assert list(blocks(world).values()) == ["unreachable"]
def test_a_question_is_answered_while_the_vm_is_blocked(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
faults = Faults(monkeypatch, world["host"])
model = ScriptedModel(
ready(), RESTATE, [call("reply", text="Because counting words is asked.")]
)
agent, transport = agent_for(world, project, model, clock=Clock())
agent.intake()
faults.down = True
say(transport, world, "why count words?") # L5: a question
assert list(blocks(world).values()) == ["unreachable"]
assert "Because counting words is asked." in said(transport)
loop = loop_of(the_item(world))
assert loop.wait == GO_AHEAD # back to its wait, restatement still up
def test_a_vm_lost_while_the_step_records_it_blocks_before_any_work(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
faults = Faults(monkeypatch, world["host"])
faults.drop_on = "base64 -d >" # writing the marker
model = ScriptedModel(ready()) # no driver run: there is no marker
agent, _ = agent_for(world, project, model, clock=Clock())
agent.intake()
assert list(blocks(world).values()) == ["unreachable"]
assert not model.turns
def test_a_lost_runs_work_is_parked_before_the_vm_is_used_again(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
faults = Faults(monkeypatch, world["host"])
clock = Clock()
model = ScriptedModel(
ready(),
RESTATE,
[
call("start_milestone", name="m"),
call("write_file", path="w.py", content="x = 1\n"),
call("run_command", command="echo GO-DOWN"),
],
[call("finish_milestone", summary="w.py, tested", final="yes")],
)
agent, transport = agent_for(world, project, model, clock=clock)
agent.intake()
faults.drop_on = "GO-DOWN"
say(transport, world, "go") # writes w.py, then loses its VM
assert blocks(world)
faults.drop_on, faults.down = "", False
parked: list[str] = []
real = agent._schedule
def schedule() -> None:
# What Gitea holds when the VM is first used again.
refs = git("--git-dir", str(world["forge"].bare), "branch", "--list")
parked.append(refs)
real()
monkeypatch.setattr(agent, "_schedule", schedule)
clock.now += RETRY
agent.intake() # answers
clock.now += SETTLE
agent.intake() # settled: parked, unblocked, and the item goes on
assert blocks(world) == {}
assert f"{the_item(world).id}-parked" in parked[-1]
forge = world["forge"]
[pr] = [n for n, p in forge.prs.items() if not p["head"].startswith("nisse-check")]
assert "w.py" in forge.files(pr)
def test_a_vm_lost_just_before_the_step_blocks_before_any_model_call(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
faults = Faults(monkeypatch, world["host"])
faults.drop_on = "git status --porcelain" # what the step checks first
model = ScriptedModel() # no model call at all
agent, _ = agent_for(world, project, model, clock=Clock())
agent.intake()
assert list(blocks(world).values()) == ["unreachable"]
def test_a_vm_lost_as_a_helper_hands_back_ends_the_drivers_run(
world: dict[str, Any], project: str, monkeypatch: pytest.MonkeyPatch
) -> None:
# Found by the property walk (seed 468): taking the helper's work back
# onto the milestone's branch failed for the lost VM, was noted as a git
# error, and the driver's model was called with the VM gone.
from test_loop_help import Spy, hand_back, helpers
faults = Faults(monkeypatch, world["host"])
class Leaving(Spy):
def complete(self, events, tools, model, system=None) -> list[Any]:
out = super().complete(events, tools, model, system)
if not self.turns: # gone as its work is taken back
faults.drop_on = "checkout -q -f -B"
return out
helper = Leaving(
[call("write_file", path="helped.py", content="H = 1\n")], [hand_back()]
)
model = ScriptedModel(
ready(),
RESTATE,
[
call("start_milestone", name="m"),
call("delegate", task="write helped.py"),
],
[call("run_command", command="echo never")], # never asked for
)
agent, transport = agent_for(
world, project, model, clock=Clock(), helpers=helpers(helper)
)
agent.intake()
say(transport, world, "go")
assert list(blocks(world).values()) == ["unreachable"]
assert the_item(world).position == READY
assert len(model.turns) == 1 # the driver's model wasn't called again