Keep agent lanes alive after controller response failures

agent/tests/test_agent.py

@@ -1,5 +1,6 @@
 import base64
 import importlib.util
+import http.client
 import io
 import json
 from pathlib import Path
@@ -392,6 +393,59 @@ class AgentTests(unittest.TestCase):
         self.agent.journal.close()
         self.temp.cleanup()
 
+    def test_controller_truncated_response_is_a_sanitized_retryable_error(self):
+        # Exercise Python's actual HTTP body reader against a truncated stream.
+        sock = MagicMock()
+        sock.makefile.return_value = io.BytesIO(b'HTTP/1.1 200 OK\r\nContent-Length: 100\r\n\r\n{"secret":')
+        response = http.client.HTTPResponse(sock)
+        response.begin()
+        with patch.object(module.urllib.request, "build_opener") as opener:
+            opener.return_value.open.return_value = response
+            with self.assertRaisesRegex(AgentError, "^Controller request failed$"):
+                self.agent.request("GET", "/api/agent/operations")
+
+    def test_read_and_health_lanes_retry_unexpected_failures_without_logging_secrets(self):
+        for lane in ("read", "health"):
+            with self.subTest(lane=lane):
+                self.agent.stopping.clear()
+                polls = []
+
+                def request(*args):
+                    polls.append(args)
+                    if len(polls) == 1:
+                        raise RuntimeError("secret controller response")
+                    self.agent.stopping.set()
+                    return {"operations": []}
+
+                with patch.object(self.agent, "request", side_effect=request), patch.object(self.agent.stopping, "wait", return_value=False), patch.object(module.sys, "stderr", new_callable=io.StringIO) as logs:
+                    self.agent.read_loop(lane)
+                self.assertEqual(len(polls), 2)
+                self.assertIn("RuntimeError", logs.getvalue())
+                self.assertNotIn("secret", logs.getvalue())
+
+    def test_heartbeat_loop_survives_unexpected_failures(self):
+        with patch.object(self.agent.stopping, "wait", side_effect=[False, False, True]), patch.object(self.agent, "heartbeat", side_effect=[RuntimeError("secret"), None]) as heartbeat, patch.object(module.sys, "stderr", new_callable=io.StringIO) as logs:
+            self.agent.heartbeat_loop()
+        self.assertEqual(heartbeat.call_count, 2)
+        self.assertIn("RuntimeError", logs.getvalue())
+        self.assertNotIn("secret", logs.getvalue())
+
+    def test_startup_and_write_loop_survive_unexpected_failures(self):
+        polls = []
+
+        def poll():
+            polls.append(True)
+            if len(polls) == 1:
+                raise RuntimeError("secret")
+            self.agent.stopping.set()
+
+        with patch.object(module.threading, "Thread"), patch.object(self.agent.stopping, "wait", return_value=False), patch.object(self.agent, "heartbeat", side_effect=[RuntimeError("secret"), None]) as heartbeat, patch.object(self.agent, "poll_operations", side_effect=poll), patch.object(module.sys, "stderr", new_callable=io.StringIO) as logs:
+            self.agent.run()
+        self.assertEqual(heartbeat.call_count, 2)
+        self.assertEqual(len(polls), 2)
+        self.assertEqual(logs.getvalue().count("RuntimeError"), 2)
+        self.assertNotIn("secret", logs.getvalue())
+
     def test_inventory_reuses_manifests_until_mtime_changes(self):
         marker = self.library / "manifest.json"
         saved = json.loads(marker.read_text())