Kill the agent's whole tree, and stop reading its errors as prose

The claude and codex CLIs spawn shells to do their work, and killing only
the direct child left those shells holding the pipes: the stdout loop
never saw EOF, so the run hung forever with the watchdog already fired,
and cleanup's subprocess.run could hang inside the stdlib the same way
after its own timeout. Both now run the CLI with its output in files
rather than pipes and put the whole tree down on a timeout, taskkill /T
on Windows and a process group everywhere else. Whether a dead resume
means "start a fresh conversation" was decided by English substrings of
stderr, which a localized CLI never says; a resumed run that exits
nonzero with no answer now retries fresh once, whatever the words were.
Recognised API trouble is the exception: a spent quota, a signed-out CLI
or a dead network is not the session's fault, and is reported as itself
rather than retried into a second copy of the same failure.

Co-Authored-By: Claude Fable 5 <[email protected]>

tests/test_cleanup.py

@@ -1,9 +1,9 @@
-"""Who cleans the transcript up, and what they are asked.
+"""Who cleans the transcript up, and what they are asked.
 
-The CLIs are faked at subprocess.run: what the tests read is the argument list
-each one is given, where the answer is picked up from, and what happens to the
-chain when the program is missing, slow or unhappy. The OpenRouter path is the
-one that was always there and is checked here only for still being taken.
+The CLIs are faked at subprocess.Popen: what the tests read is the argument
+list each one is given, where the answer is picked up from, and what happens to
+the chain when the program is missing, slow or unhappy. The OpenRouter path is
+the one that was always there and is checked here only for still being taken.
 """
 
 import os
@@ -18,18 +18,26 @@ from tests.support import DikteTest, fake_urlopen, sent_json, url_error
 from tests.test_api import FakeServer, chat_reply
 
 
-def fake_run(stdout="", code=0, stderr="", last_message=""):
-    """Stand in for subprocess.run, writing the file Codex would have written."""
+def fake_cli(stdout="", code=0, stderr="", last_message=""):
+    """Stand in for subprocess.Popen.
+
+    _output hands the process a temporary file for each stream, so the fake
+    writes into those, plus the file Codex would have written on its way out.
+    """
     calls = []
 
-    def run(cmd, **kwargs):
+    def popen(cmd, **kwargs):
         calls.append(cmd)
+        kwargs["stdout"].write(stdout.encode("utf-8"))
+        kwargs["stderr"].write(stderr.encode("utf-8"))
         if last_message and "-o" in cmd:
             with open(cmd[cmd.index("-o") + 1], "w", encoding="utf-8") as fh:
                 fh.write(last_message)
-        return subprocess.CompletedProcess(cmd, code, stdout, stderr)
+        proc = mock.Mock()
+        proc.returncode = code
+        return proc
 
-    return mock.patch.object(subprocess, "run", side_effect=run), calls
+    return mock.patch.object(subprocess, "Popen", side_effect=popen), calls
 
 
 class Provider(DikteTest):
@@ -80,7 +88,7 @@ class OpenRouter(DikteTest):
 
     def test_no_cli_is_started_for_it(self):
         conf = self.config(openrouter_api_key="sk-or-test")
-        patcher, calls = fake_run(stdout="never")
+        patcher, calls = fake_cli(stdout="never")
         with patcher, mock.patch.object(api, "cleanup", return_value="Done."):
             cleanup.run("uh, done", conf, "the rules")
         self.assertEqual(calls, [])
@@ -93,7 +101,7 @@ class ClaudeCode(DikteTest):
         self.patch_attr(cleanup.shutil, "which", lambda name: f"/usr/bin/{name}")
 
     def run_cleanup(self, text="uh, book it", **kwargs):
-        patcher, calls = fake_run(**kwargs)
+        patcher, calls = fake_cli(**kwargs)
         with patcher:
             answer = cleanup.run(text, self.conf, "the rules")
         return answer, calls[0]
@@ -146,14 +154,18 @@ class ClaudeCode(DikteTest):
             self.run_cleanup(stdout="Book it.")
         self.assertIn("claude", str(caught.exception))
 
-    def test_a_run_that_never_ends(self):
-        def run(cmd, **kwargs):
-            raise subprocess.TimeoutExpired(cmd, 180)
+    def test_a_run_that_never_ends_is_killed_with_its_whole_tree(self):
+        def popen(cmd, **kwargs):
+            proc = mock.Mock()
+            proc.wait.side_effect = subprocess.TimeoutExpired(cmd, 180)
+            return proc
 
-        with mock.patch.object(subprocess, "run", side_effect=run):
+        with mock.patch.object(subprocess, "Popen", side_effect=popen), \
+                mock.patch.object(cleanup.assistant, "kill_tree") as kill:
             with self.assertRaises(cleanup.CleanupError) as caught:
                 cleanup.run("uh, book it", self.conf, "the rules")
         self.assertIn("180", str(caught.exception))
+        kill.assert_called_once()
 
 
 class Codex(DikteTest):
@@ -163,7 +175,7 @@ class Codex(DikteTest):
         self.patch_attr(cleanup.shutil, "which", lambda name: f"/usr/bin/{name}")
 
     def run_cleanup(self, text="uh, book it", **kwargs):
-        patcher, calls = fake_run(**kwargs)
+        patcher, calls = fake_cli(**kwargs)
         with patcher:
             answer = cleanup.run(text, self.conf, "the rules")
         return answer, calls[0]
@@ -280,7 +292,8 @@ class Here(DikteTest):
         self.assertIn("out of memory", str(caught.exception))
 
     def test_no_cli_is_started_for_it(self):
-        patcher, calls = fake_run(stdout="never")
+        patcher, calls = fake_cli(stdout="never")
         with patcher, fake_urlopen(chat_reply("Done.")):
             cleanup.run("uh, done", self.conf, "the rules")
         self.assertEqual(calls, [])
+