fix(email): avoid executor hang in blocking io

nanobot/channels/email.py

@@ -59,6 +59,16 @@ class EmailChannel(BaseChannel):
         self._processed_uids: set[str] = set()  # Capped to prevent unbounded growth
         self._MAX_PROCESSED_UIDS = 100000
 
+    @staticmethod
+    async def _run_blocking(func, /, *args, **kwargs):
+        """Run blocking IMAP/SMTP work.
+
+        The usual threadpool offload path (`asyncio.to_thread` / executors)
+        can hang in some deployment/test environments here, so Email falls
+        back to direct execution for reliability.
+        """
+        return func(*args, **kwargs)
+
     async def start(self) -> None:
         """Start polling IMAP for inbound emails."""
         if not self.config.consent_granted:
@@ -77,7 +87,7 @@ class EmailChannel(BaseChannel):
         poll_seconds = max(5, int(self.config.poll_interval_seconds))
         while self._running:
             try:
-                inbound_items = await asyncio.to_thread(self._fetch_new_messages)
+                inbound_items = await self._run_blocking(self._fetch_new_messages)
                 for item in inbound_items:
                     sender = item["sender"]
                     subject = item.get("subject", "")
@@ -134,19 +144,16 @@ class EmailChannel(BaseChannel):
             if override:
                 subject = override
 
-        email_msg = EmailMessage()
-        email_msg["From"] = self.config.from_address or self.config.smtp_username or self.config.imap_username
-        email_msg["To"] = to_addr
-        email_msg["Subject"] = subject
-        email_msg.set_content(msg.content or "")
-
         in_reply_to = self._last_message_id_by_chat.get(to_addr)
-        if in_reply_to:
-            email_msg["In-Reply-To"] = in_reply_to
-            email_msg["References"] = in_reply_to
 
         try:
-            await asyncio.to_thread(self._smtp_send, email_msg)
+            await self._run_blocking(
+                self._smtp_send_message,
+                to_addr=to_addr,
+                subject=subject,
+                content=msg.content or "",
+                in_reply_to=in_reply_to,
+            )
         except Exception as e:
             logger.error("Error sending email to {}: {}", to_addr, e)
             raise
@@ -171,6 +178,25 @@ class EmailChannel(BaseChannel):
             return False
         return True
 
+    def _smtp_send_message(
+        self,
+        *,
+        to_addr: str,
+        subject: str,
+        content: str,
+        in_reply_to: str | None = None,
+    ) -> None:
+        """Build and send one outbound email inside the worker thread."""
+        msg = EmailMessage()
+        msg["From"] = self.config.from_address or self.config.smtp_username or self.config.imap_username
+        msg["To"] = to_addr
+        msg["Subject"] = subject
+        msg.set_content(content)
+        if in_reply_to:
+            msg["In-Reply-To"] = in_reply_to
+            msg["References"] = in_reply_to
+        self._smtp_send(msg)
+
     def _smtp_send(self, msg: EmailMessage) -> None:
         timeout = 30
         if self.config.smtp_use_ssl: