fix: retry transient IMAP aborts

src/github_agent_bridge/reader.py

@@ -39,6 +39,15 @@ def __init__(self, config: ImapConfig, queue: JobQueue, policy: Policy, mark_see
         self.mark_seen = mark_seen
 
     def fetch_once(self) -> int:
+        for attempt in range(2):
+            try:
+                return self._fetch_once()
+            except imaplib.IMAP4.abort:
+                if attempt:
+                    raise
+        return 0
+
+    def _fetch_once(self) -> int:
         last_uid = int(self.queue.get_state("last_uid", "0") or 0)
         count = 0
         imap = imaplib.IMAP4_SSL(self.config.host, self.config.port)

tests/test_reader.py

@@ -0,0 +1,67 @@
+import imaplib
+
+import pytest
+
+from github_agent_bridge.reader import ImapConfig, ImapReader
+
+
+class QueueStub:
+    def get_state(self, key, default=None):
+        return default
+
+
+class AbortOnSelect:
+    def __init__(self, *args):
+        self.logged_out = False
+
+    def login(self, username, password):
+        return "OK", []
+
+    def select(self, mailbox):
+        raise imaplib.IMAP4.abort("command: SELECT => socket error: EOF")
+
+    def logout(self):
+        self.logged_out = True
+
+
+class EmptyMailbox:
+    def __init__(self, *args):
+        self.logged_out = False
+
+    def login(self, username, password):
+        return "OK", []
+
+    def select(self, mailbox):
+        return "OK", []
+
+    def uid(self, command, *args):
+        assert command == "search"
+        return "OK", [b""]
+
+    def logout(self):
+        self.logged_out = True
+
+
+def make_reader():
+    config = ImapConfig("imap.example.com", 993, "bot@example.com", "secret")
+    return ImapReader(config, QueueStub(), object())
+
+
+def test_fetch_once_reconnects_after_imap_abort(monkeypatch):
+    connections = [AbortOnSelect(), EmptyMailbox()]
+
+    monkeypatch.setattr(imaplib, "IMAP4_SSL", lambda *args: connections.pop(0))
+
+    assert make_reader().fetch_once() == 0
+    assert connections == []
+
+
+def test_fetch_once_raises_after_second_imap_abort(monkeypatch):
+    connections = [AbortOnSelect(), AbortOnSelect()]
+
+    monkeypatch.setattr(imaplib, "IMAP4_SSL", lambda *args: connections.pop(0))
+
+    with pytest.raises(imaplib.IMAP4.abort, match="socket error: EOF"):
+        make_reader().fetch_once()
+
+    assert connections == []