Reject odd-length tag UIDs

spoolman/tags.py

@@ -82,6 +82,8 @@ def normalize_uid(uid: str) -> str:
         raise ValueError("A tag UID must not be empty.")
     if not _HEX_ONLY.match(normalized):
         raise ValueError(f'"{uid}" is not a valid tag UID. A UID must be hexadecimal.')
+    if len(normalized) % 2:
+        raise ValueError("A tag UID must contain a whole number of bytes (an even number of hex characters).")
     if len(normalized) > UID_MAX_LENGTH:
         raise ValueError(f"A tag UID can be at most {UID_MAX_LENGTH} hex characters.")
     return normalized