Import vendored chattolib absolutely and fail loudly

vendor/ is already on sys.path and chattolib's own modules import each
other absolutely, so the additional relative ".vendor.chattolib" imports
loaded a second, distinct copy of every module — isinstance() checks
across the two copies would silently fail.

A failed import was previously only logged, deferring the failure to a
confusing NameError deep inside the adapter; re-raise instead.

adapter.py

@@ -52,29 +52,35 @@ from gateway.config import Platform, PlatformConfig
 # Using vendored chattolib from vendor/chattolib/
 # See vendor_chattolib.sh for how to update the vendored copy
 
+# Absolute imports — vendor/ is on sys.path (see above) and chattolib's own
+# modules import each other absolutely. Mixing in relative ".vendor.chattolib"
+# imports would load a second, distinct copy of every module, so isinstance()
+# checks across the two copies would silently fail.
 try:
-    # Try vendored chattolib first
-    from .vendor.chattolib.client import (
+    from chattolib.client import (
         ChattoClient,
     )
-    from .vendor.chattolib.exceptions import (
+    from chattolib.exceptions import (
         ChattoAuthError,
         ChattoError,
     )
-    from .vendor.chattolib.realtime import (
+    from chattolib.realtime import (
         ChattoRealtimeError,
         ChattoRealtimeCloseError, RealtimeEvent,
         stream_events
     )
-    from .vendor.chattolib.realtime_types import (
+    from chattolib.realtime_types import (
         MessagePostedPayload
     )
-    from .vendor.chattolib.types import (
+    from chattolib.types import (
         PresenceStatus, RoomKind, User
     )
 
 except ImportError as e:
+    # Fail loudly: continuing here only defers the failure to a confusing
+    # NameError somewhere deep in the adapter.
     logger.error("Chatto: failed to import vendored chattolib: %s", e)
+    raise
 
 
 from .platform_config import (
@@ -1254,11 +1260,10 @@ def hermes_check_fn() -> bool:
     """Check if Chatto is configured and dependencies are available.
     Add real logic?! Or just .. there are no dependencies.. always return true. Really. Docs suck."""
     try:
-        from .vendor.chattolib.client import ChattoClient
+        import chattolib.client  # noqa: F401 — vendored dependency probe
         return True
     except ImportError:
         return False
-    return True
 
 
 # ---------------------------------------------------------------------------

platform_config.py

@@ -16,15 +16,17 @@ vendor_dir = current_dir / "vendor"
 if str(vendor_dir) not in sys.path:
     sys.path.insert(0, str(vendor_dir))
 
-from dataclasses import dataclass
 import logging
-import os
-from typing import Any, Dict, Optional
+from typing import Any, Dict, Generic, Optional, TypeVar
 
 from gateway.config import PlatformConfig
 import utils
 
-from .vendor.chattolib.client import ChattoClient
+# Absolute import — the vendor dir is on sys.path (see above) and chattolib's
+# own modules import each other absolutely ("from chattolib.x import y").
+# Importing it relatively as well would load a *second* copy of every module
+# under a different name, so isinstance() checks across the two would fail.
+from chattolib.client import ChattoClient
 
 logger = logging.getLogger(__name__)