fix(smolmachines): stop VM before pack commit, with confirm prompt

smolvm pack create --from-vm requires the VM to be stopped. Add
machine_is_running() to smolvm.py (via machine ls --json state field),
and add the same confirm-stop flow to SmolmachinesFreezer that was
originally designed for macos-container: if running, prompt the user,
stop the VM, then pack. Already-stopped VMs are packed directly.

bot_bottle/backend/smolmachines/freezer.py

@@ -2,15 +2,31 @@
 
 from __future__ import annotations
 
+import sys
+
 from .. import ActiveAgent
-from ..freeze import Freezer
+from ..freeze import CommitCancelled, Freezer
-from .smolvm import pack_create_from_vm
+from .smolvm import machine_is_running, machine_stop, pack_create_from_vm
 from ...bottle_state import bottle_state_dir
 from ...log import info
 
 
+def _read_tty_line() -> str:
+    """Read one line from /dev/tty, falling back to stdin."""
+    try:
+        with open("/dev/tty", "r", encoding="utf-8") as tty:
+            return tty.readline().rstrip("\n")
+    except OSError:
+        return sys.stdin.readline().rstrip("\n")
+
+
 class SmolmachinesFreezer(Freezer):
-    """Freezes a smolmachines bottle via `smolvm pack create --from-vm`."""
+    """Freezes a smolmachines bottle via `smolvm pack create --from-vm`.
+
+    `smolvm pack create --from-vm` requires the VM to be stopped first.
+    If the VM is running the freezer prompts the user to confirm the stop
+    before proceeding. The VM remains stopped after commit; use
+    `./cli.py resume` to restart."""
 
     backend_name = "smolmachines"
 
@@ -18,6 +34,16 @@ class SmolmachinesFreezer(Freezer):
         machine = f"bot-bottle-{agent.slug}"
         output = bottle_state_dir(agent.slug) / "committed-smolmachine"
         output.parent.mkdir(parents=True, exist_ok=True)
+        if machine_is_running(machine):
+            sys.stderr.write(
+                f"bot-bottle: bottle {agent.slug!r} is running; "
+                "commit will stop it. Continue? [y/N] "
+            )
+            sys.stderr.flush()
+            reply = _read_tty_line().strip().lower()
+            if reply not in ("y", "yes"):
+                raise CommitCancelled
+            machine_stop(machine)
         pack_create_from_vm(machine, output)
         artifact = output.with_name(f"{output.name}.smolmachine")
         return str(artifact)

bot_bottle/backend/smolmachines/smolvm.py

@@ -25,6 +25,7 @@ smolvm binary."""
 
 from __future__ import annotations
 
+import json
 import shutil
 import subprocess
 import time
@@ -153,6 +154,21 @@ def machine_create(
     _smolvm(*args)
 
 
+def machine_is_running(name: str) -> bool:
+    """Return True if the named VM is in the 'running' state."""
+    result = _smolvm("machine", "ls", "--json", check=False)
+    if result.returncode != 0:
+        return False
+    try:
+        machines = json.loads(result.stdout or "[]")
+    except ValueError:
+        return False
+    return any(
+        isinstance(m, dict) and m.get("name") == name and m.get("state") == "running"
+        for m in machines
+    )
+
+
 def machine_start(name: str) -> None:
     """`smolvm machine start --name NAME`."""
     _smolvm("machine", "start", "--name", name)

tests/unit/test_backend_freezer.py

@@ -183,16 +183,21 @@ class TestSmolmachinesFreezer(_FakeHomeMixin, unittest.TestCase):
     def tearDown(self):
         self._teardown_fake_home()
 
-    def test_packs_vm_and_records_artifact(self):
+    def _write_meta(self, slug: str) -> None:
-        slug = "dev-abc12"
         bottle_state.write_metadata(bottle_state.BottleMetadata(
             identity=slug, agent_name="dev", cwd="", copy_cwd=False,
             started_at="t", backend="smolmachines",
         ))
+
+    def test_packs_stopped_vm_directly(self):
+        slug = "dev-abc12"
+        self._write_meta(slug)
         freezer = SmolmachinesFreezer()
         agent = _make_agent(slug, "smolmachines")
 
-        with patch("bot_bottle.backend.smolmachines.freezer.pack_create_from_vm") as mock_pack, \
+        with patch("bot_bottle.backend.smolmachines.freezer.machine_is_running",
+                   return_value=False), \
+             patch("bot_bottle.backend.smolmachines.freezer.pack_create_from_vm") as mock_pack, \
              patch("bot_bottle.backend.freeze.info"), \
              patch("bot_bottle.backend.smolmachines.freezer.info"):
             freezer.commit(agent)
@@ -203,6 +208,42 @@ class TestSmolmachinesFreezer(_FakeHomeMixin, unittest.TestCase):
         self.assertEqual(expected_artifact, bottle_state.read_committed_image(slug))
         self.assertTrue(bottle_state.is_preserved(slug))
 
+    def test_stops_running_vm_on_yes(self):
+        slug = "dev-abc12"
+        self._write_meta(slug)
+        freezer = SmolmachinesFreezer()
+        agent = _make_agent(slug, "smolmachines")
+
+        with patch("bot_bottle.backend.smolmachines.freezer.machine_is_running",
+                   return_value=True), \
+             patch("bot_bottle.backend.smolmachines.freezer._read_tty_line", return_value="y"), \
+             patch("bot_bottle.backend.smolmachines.freezer.machine_stop") as mock_stop, \
+             patch("bot_bottle.backend.smolmachines.freezer.pack_create_from_vm") as mock_pack, \
+             patch("bot_bottle.backend.freeze.info"), \
+             patch("bot_bottle.backend.smolmachines.freezer.info"):
+            freezer.commit(agent)
+
+        mock_stop.assert_called_once_with(f"bot-bottle-{slug}")
+        mock_pack.assert_called_once()
+
+    def test_raises_commit_cancelled_on_no(self):
+        slug = "dev-abc12"
+        self._write_meta(slug)
+        freezer = SmolmachinesFreezer()
+        agent = _make_agent(slug, "smolmachines")
+
+        with patch("bot_bottle.backend.smolmachines.freezer.machine_is_running",
+                   return_value=True), \
+             patch("bot_bottle.backend.smolmachines.freezer._read_tty_line", return_value="n"), \
+             patch("bot_bottle.backend.smolmachines.freezer.machine_stop") as mock_stop, \
+             patch("bot_bottle.backend.smolmachines.freezer.pack_create_from_vm") as mock_pack:
+            from bot_bottle.backend.freeze import CommitCancelled
+            with self.assertRaises(CommitCancelled):
+                freezer.commit(agent)
+
+        mock_stop.assert_not_called()
+        mock_pack.assert_not_called()
+
 
 if __name__ == "__main__":
     unittest.main()