fix: Improve dynamo.connect Error Reporting

This change adds checking for remote vs. local descriptors for count and size of each.
An error is generated from the Python side which contains useful information for developers to self-resolve with.

Author: whoisj

examples/multimodal/connect/__init__.py

@@ -208,10 +208,17 @@ def __init__(
         if isinstance(remote_descriptors, list) and len(remote_descriptors) == 1:
             remote_descriptors = remote_descriptors[0]
 
-        if (isinstance(local_descriptors, list) and isinstance(remote_descriptors, list) and len(local_descriptors) != len(remote_descriptors)):
-            raise ValueError("When `local_descriptors` and `remote_descriptors` are lists, they must have the same length.")
-        elif isinstance(local_descriptors, list) != isinstance(remote_descriptors, list):
+        if isinstance(local_descriptors, list) != isinstance(remote_descriptors, list):
             raise ValueError("Both `local_descriptors` and `remote_descriptors` must be either lists or single descriptors.")
+        # Ensure that the descriptors are of the same size here to avoid confusing errors from NIXL.
+        if isinstance(local_descriptors, list) and isinstance(remote_descriptors, list):
+            if len(local_descriptors) != len(remote_descriptors):
+                raise ValueError(f"When `local_descriptors` and `remote_descriptors` are lists, they must have the same length. {len(local_descriptors)} != {len(remote_descriptors)}.")
+            for i in range(len(local_descriptors)):
+                if local_descriptors[i].size != remote_descriptors[i].size:
+                    raise ValueError(f"Descriptor length mismatch: `local_descriptors` and `remote_descriptors` descriptor at {i} must have the same size. {local_descriptors[i].size} != {remote_descriptors[i].size}.")
+        elif (isinstance(local_descriptors, Descriptor) and isinstance(remote_descriptors, Descriptor)) and local_descriptors.size != remote_descriptors.size:
+                raise ValueError(f"Local and remote descriptors must be the same size. {local_descriptors.size} != {remote_descriptors.size}.")
         if not isinstance(notification_key, str):
             raise TypeError("Argument `notification_key` must be `str`.")
         if len(notification_key) == 0: