fix(gateway): harden email adapter against malformed IMAP responses

gateway/platforms/email.py

@@ -308,7 +308,15 @@ def _fetch_new_messages(self) -> List[Dict[str, Any]]:
                 if status != "OK":
                     continue
 
-                raw_email = msg_data[0][1]
+                # IMAP fetch can return unexpected structures (e.g. a single
+                # bytes item instead of a list of tuples).  Guard against
+                # IndexError / TypeError so one malformed response doesn't
+                # crash the entire polling loop.
+                try:
+                    raw_email = msg_data[0][1]
+                except (IndexError, TypeError):
+                    logger.warning("[Email] Unexpected IMAP response structure for UID %s, skipping", uid)
+                    continue
                 msg = email_lib.message_from_bytes(raw_email)
 
                 sender_raw = msg.get("From", "")
@@ -438,7 +446,8 @@ def _send_email(
             msg["In-Reply-To"] = original_msg_id
             msg["References"] = original_msg_id
 
-        msg_id = f"<hermes-{uuid.uuid4().hex[:12]}@{self._address.split('@')[1]}>"
+        domain = self._address.rsplit("@", 1)[-1] if "@" in self._address else "localhost"
+        msg_id = f"<hermes-{uuid.uuid4().hex[:12]}@{domain}>"
         msg["Message-ID"] = msg_id
 
         msg.attach(MIMEText(body, "plain", "utf-8"))
@@ -515,7 +524,8 @@ def _send_email_with_attachment(
             msg["In-Reply-To"] = original_msg_id
             msg["References"] = original_msg_id
 
-        msg_id = f"<hermes-{uuid.uuid4().hex[:12]}@{self._address.split('@')[1]}>"
+        domain = self._address.rsplit("@", 1)[-1] if "@" in self._address else "localhost"
+        msg_id = f"<hermes-{uuid.uuid4().hex[:12]}@{domain}>"
         msg["Message-ID"] = msg_id
 
         if body:

tests/gateway/test_email_robustness.py

@@ -0,0 +1,180 @@
+"""Tests for email adapter robustness fixes.
+
+Validates that:
+- Malformed IMAP fetch responses are skipped instead of crashing
+- Message-ID generation handles missing '@' in EMAIL_ADDRESS
+"""
+
+import email as email_lib
+import uuid
+from unittest.mock import MagicMock, patch
+
+import pytest
+
+
+# ---------------------------------------------------------------------------
+# Test: IMAP response structure guard (msg_data[0][1])
+# ---------------------------------------------------------------------------
+
+class TestImapResponseGuard:
+    """_fetch_new_messages should skip messages with unexpected IMAP structure."""
+
+    def _build_adapter(self):
+        """Create a minimal EmailAdapter with mocked config."""
+        # Patch env vars and config before import
+        env = {
+            "EMAIL_ADDRESS": "agent@example.com",
+            "EMAIL_PASSWORD": "secret",
+            "EMAIL_IMAP_HOST": "imap.example.com",
+            "EMAIL_SMTP_HOST": "smtp.example.com",
+            "EMAIL_IMAP_PORT": "993",
+            "EMAIL_SMTP_PORT": "587",
+            "EMAIL_POLL_INTERVAL": "15",
+        }
+        with patch.dict("os.environ", env):
+            from gateway.platforms.email import EmailAdapter
+            from gateway.config import PlatformConfig, Platform
+
+            config = MagicMock(spec=PlatformConfig)
+            config.extra = {}
+            adapter = EmailAdapter(config)
+        return adapter
+
+    def _make_raw_email(self, sender="user@test.com", subject="Hello"):
+        """Build a minimal RFC822 email as bytes."""
+        from email.mime.text import MIMEText
+        msg = MIMEText("Test body", "plain", "utf-8")
+        msg["From"] = sender
+        msg["Subject"] = subject
+        msg["Message-ID"] = f"<{uuid.uuid4().hex[:8]}@test.com>"
+        return msg.as_bytes()
+
+    def test_normal_imap_response(self):
+        """Normal tuple structure should parse correctly."""
+        adapter = self._build_adapter()
+        raw = self._make_raw_email()
+
+        mock_imap = MagicMock()
+        mock_imap.login.return_value = ("OK", [])
+        mock_imap.select.return_value = ("OK", [])
+        mock_imap.uid.side_effect = [
+            ("OK", [b"1"]),                       # search
+            ("OK", [(b"1 (RFC822 {123}", raw)]),  # fetch — normal
+        ]
+
+        with patch("gateway.platforms.email.imaplib.IMAP4_SSL", return_value=mock_imap):
+            results = adapter._fetch_new_messages()
+
+        assert len(results) == 1
+        assert results[0]["sender_addr"] == "user@test.com"
+
+    def test_malformed_imap_response_none_element(self):
+        """If msg_data[0] is None, skip without crashing."""
+        adapter = self._build_adapter()
+
+        mock_imap = MagicMock()
+        mock_imap.login.return_value = ("OK", [])
+        mock_imap.select.return_value = ("OK", [])
+        mock_imap.uid.side_effect = [
+            ("OK", [b"1"]),      # search
+            ("OK", [None]),      # fetch — malformed (None element)
+        ]
+
+        with patch("gateway.platforms.email.imaplib.IMAP4_SSL", return_value=mock_imap):
+            results = adapter._fetch_new_messages()
+
+        assert len(results) == 0  # skipped, no crash
+
+    def test_malformed_imap_response_empty_list(self):
+        """If msg_data is empty, skip without crashing."""
+        adapter = self._build_adapter()
+
+        mock_imap = MagicMock()
+        mock_imap.login.return_value = ("OK", [])
+        mock_imap.select.return_value = ("OK", [])
+        mock_imap.uid.side_effect = [
+            ("OK", [b"1"]),  # search
+            ("OK", []),      # fetch — empty
+        ]
+
+        with patch("gateway.platforms.email.imaplib.IMAP4_SSL", return_value=mock_imap):
+            results = adapter._fetch_new_messages()
+
+        assert len(results) == 0
+
+    def test_malformed_imap_response_bytes_only(self):
+        """If msg_data[0] is a plain bytes (not a tuple), skip."""
+        adapter = self._build_adapter()
+
+        mock_imap = MagicMock()
+        mock_imap.login.return_value = ("OK", [])
+        mock_imap.select.return_value = ("OK", [])
+        mock_imap.uid.side_effect = [
+            ("OK", [b"1"]),            # search
+            ("OK", [b"raw bytes"]),    # fetch — bytes, not tuple
+        ]
+
+        with patch("gateway.platforms.email.imaplib.IMAP4_SSL", return_value=mock_imap):
+            results = adapter._fetch_new_messages()
+
+        assert len(results) == 0
+
+
+# ---------------------------------------------------------------------------
+# Test: Message-ID domain extraction (split('@') safety)
+# ---------------------------------------------------------------------------
+
+class TestMessageIdDomainSafety:
+    """Message-ID generation should not crash when EMAIL_ADDRESS has no @."""
+
+    def test_normal_address_extracts_domain(self):
+        """Standard email address extracts domain correctly."""
+        env = {
+            "EMAIL_ADDRESS": "agent@example.com",
+            "EMAIL_PASSWORD": "secret",
+            "EMAIL_IMAP_HOST": "imap.example.com",
+            "EMAIL_SMTP_HOST": "smtp.example.com",
+        }
+        with patch.dict("os.environ", env):
+            from gateway.platforms.email import EmailAdapter
+            config = MagicMock()
+            config.extra = {}
+            adapter = EmailAdapter(config)
+
+        # Simulate the domain extraction logic used in _send_email
+        domain = adapter._address.rsplit("@", 1)[-1] if "@" in adapter._address else "localhost"
+        assert domain == "example.com"
+
+    def test_missing_at_sign_falls_back_to_localhost(self):
+        """Misconfigured address without @ should not crash."""
+        env = {
+            "EMAIL_ADDRESS": "no-at-sign",
+            "EMAIL_PASSWORD": "secret",
+            "EMAIL_IMAP_HOST": "imap.example.com",
+            "EMAIL_SMTP_HOST": "smtp.example.com",
+        }
+        with patch.dict("os.environ", env):
+            from gateway.platforms.email import EmailAdapter
+            config = MagicMock()
+            config.extra = {}
+            adapter = EmailAdapter(config)
+
+        domain = adapter._address.rsplit("@", 1)[-1] if "@" in adapter._address else "localhost"
+        assert domain == "localhost"
+
+    def test_empty_address_falls_back_to_localhost(self):
+        """Empty EMAIL_ADDRESS should not crash."""
+        env = {
+            "EMAIL_ADDRESS": "",
+            "EMAIL_PASSWORD": "secret",
+            "EMAIL_IMAP_HOST": "imap.example.com",
+            "EMAIL_SMTP_HOST": "smtp.example.com",
+        }
+        with patch.dict("os.environ", env):
+            from gateway.platforms.email import EmailAdapter
+            config = MagicMock()
+            config.extra = {}
+            adapter = EmailAdapter(config)
+
+        domain = adapter._address.rsplit("@", 1)[-1] if "@" in adapter._address else "localhost"
+        assert domain == "localhost"