From 08815e6c7434cf57edf6eaf36e5a3014063f0cc5 Mon Sep 17 00:00:00 2001
From: honor2030 <20864931+honor2030@users.noreply.github.com>
Date: Tue, 12 May 2026 13:39:51 +0900
Subject: [PATCH] fix: handle empty IPC responses

---
 src/browser_harness/_ipc.py  | 10 +++++++---
 src/browser_harness/admin.py |  2 ++
 tests/unit/test_admin.py     | 20 ++++++++++++++++++++
 tests/unit/test_ipc.py       | 24 ++++++++++++++++++++++++
 4 files changed, 53 insertions(+), 3 deletions(-)

diff --git a/src/browser_harness/_ipc.py b/src/browser_harness/_ipc.py
index 2d265766..ba7f8538 100644
--- a/src/browser_harness/_ipc.py
+++ b/src/browser_harness/_ipc.py
@@ -91,15 +91,19 @@ def connect(name, timeout=1.0):
 
 def request(c, token, req):
     """One-shot send + recv + parse on an open socket. Injects token on Windows.
-    Returns the parsed JSON response. Caller closes the socket."""
+    Returns the parsed JSON response. Caller closes the socket.
+    Raises ConnectionError if the peer closes before sending any response."""
     if token: req = {**req, "token": token}
     c.sendall((json.dumps(req) + "\n").encode())
     data = b""
     while not data.endswith(b"\n"):
         chunk = c.recv(1 << 16)
-        if not chunk: break
+        if not chunk:
+            if not data:
+                raise ConnectionError("IPC peer closed without a response")
+            break
         data += chunk
-    return json.loads(data or b"{}")
+    return json.loads(data)
 
 
 def ping(name, timeout=1.0):
diff --git a/src/browser_harness/admin.py b/src/browser_harness/admin.py
index f4b634d0..da3049a2 100644
--- a/src/browser_harness/admin.py
+++ b/src/browser_harness/admin.py
@@ -191,6 +191,8 @@ def _daemon_browser_connection(name):
     try:
         c, token = ipc.connect(name, timeout=1.0)
         response = ipc.request(c, token, {"meta": "connection_status"})
+        if not isinstance(response, dict):
+            return None
         if "error" in response:
             return None
         page = response.get("page")
diff --git a/tests/unit/test_admin.py b/tests/unit/test_admin.py
index 6826b399..5872d4f9 100644
--- a/tests/unit/test_admin.py
+++ b/tests/unit/test_admin.py
@@ -123,6 +123,26 @@ def test_browser_connections_returns_attached_page(monkeypatch):
     ]
 
 
+def test_browser_connections_skips_daemon_that_closes_without_response(monkeypatch):
+    monkeypatch.setattr(admin, "_daemon_endpoint_names", lambda: ["default", "stale"])
+
+    def fake_connect(name, timeout=1.0):
+        if name == "stale":
+            return FakeSocket(b""), None
+        return FakeSocket(), None
+
+    monkeypatch.setattr(admin.ipc, "connect", fake_connect)
+
+    assert admin.browser_connections() == [{"name": "default", "page": None}]
+
+
+def test_browser_connections_skips_non_dict_connection_status_response(monkeypatch):
+    monkeypatch.setattr(admin, "_daemon_endpoint_names", lambda: ["stale"])
+    monkeypatch.setattr(admin.ipc, "connect", lambda name, timeout=1.0: (FakeSocket(b"[]\n"), None))
+
+    assert admin.browser_connections() == []
+
+
 def test_chrome_running_detects_helium_on_linux(monkeypatch):
     monkeypatch.setattr("platform.system", lambda: "Linux")
     monkeypatch.setattr(
diff --git a/tests/unit/test_ipc.py b/tests/unit/test_ipc.py
index 96e2dbc6..28d64cec 100644
--- a/tests/unit/test_ipc.py
+++ b/tests/unit/test_ipc.py
@@ -1,6 +1,30 @@
+import pytest
+
 from browser_harness import _ipc as ipc
 
 
+# --- request(): EOF handling ---
+
+class _EOFConn:
+    def __init__(self):
+        self.sent = b""
+
+    def sendall(self, data):
+        self.sent += data
+
+    def recv(self, _size):
+        return b""
+
+
+def test_request_raises_connection_error_when_peer_closes_without_response():
+    conn = _EOFConn()
+
+    with pytest.raises(ConnectionError, match="closed without a response"):
+        ipc.request(conn, None, {"meta": "ping"})
+
+    assert conn.sent
+
+
 # --- identify(): ping payload sanitation ---
 
 class _FakeConn: