Merge branch 'issue1564' of https://github.com/satvshr/openml-python into issue1564

Author: satvshr

openml/_api_calls.py

@@ -24,8 +24,8 @@
 
 from .__version__ import __version__
 from .exceptions import (
+    OpenMLAuthenticationError,
     OpenMLHashException,
-    OpenMLNotAuthorizedError,
     OpenMLServerError,
     OpenMLServerException,
     OpenMLServerNoResult,
@@ -518,11 +518,7 @@ def __parse_server_exception(
         400,  # run/42 delete
         460,  # task/42 delete
     ]:
-        msg = (
-            f"The API call {url} requires authentication via an API key.\nPlease configure "
-            "OpenML-Python to use your API as described in this example:"
-            "\nhttps://openml.github.io/openml-python/latest/examples/Basics/introduction_tutorial/#authentication"
-        )
-        return OpenMLNotAuthorizedError(message=msg)
+        msg = f"The API call {url} requires authentication via an API key."
+        return OpenMLAuthenticationError(message=msg)
 
     return OpenMLServerException(code=code, message=full_message, url=url)

openml/exceptions.py

@@ -63,5 +63,28 @@ class OpenMLNotAuthorizedError(OpenMLServerError):
     """Indicates an authenticated user is not authorized to execute the requested action."""
 
 
+class OpenMLAuthenticationError(OpenMLServerError):
+    """Exception raised when API authentication fails.
+
+    This typically occurs when:
+    - No API key is configured
+    - The API key is invalid or expired
+    - The API key format is incorrect
+
+    This is different from authorization (OpenMLNotAuthorizedError), which occurs
+    when a valid API key lacks permissions for the requested operation.
+    """
+
+    def __init__(self, message: str):
+        help_text = (
+            "\n\nTo fix this:\n"
+            "1. Get your API key from https://www.openml.org/\n"
+            "   (you'll need to register for a free account if you don't have one)\n"
+            "2. Configure your API key by following the authentication guide:\n"
+            "   https://openml.github.io/openml-python/latest/examples/Basics/introduction_tutorial/#authentication"
+        )
+        super().__init__(message + help_text)
+
+
 class ObjectNotPublishedError(PyOpenMLError):
     """Indicates an object has not been published yet."""

openml/tasks/functions.py

@@ -426,6 +426,9 @@ def get_task(
         # Including class labels as part of task meta data handles
         #   the case where data download was initially disabled
         if isinstance(task, (OpenMLClassificationTask, OpenMLLearningCurveTask)):
+            assert task.target_name is not None, (
+                "Supervised tasks must define a target feature before retrieving class labels."
+            )
             task.class_labels = dataset.retrieve_class_labels(task.target_name)
         # Clustering tasks do not have class labels
         # and do not offer download_split
@@ -599,6 +602,7 @@ def create_task(
         )
 
     return task_cls(
+        task_id=None,
         task_type_id=task_type,
         task_type="None",  # TODO: refactor to get task type string from ID.
         data_set_id=dataset_id,