Remove deprecated TaskMixin class

airflow/models/taskmixin.py

@@ -16,11 +16,10 @@
 # under the License.
 from __future__ import annotations
 
-import warnings
 from abc import ABCMeta, abstractmethod
 from typing import TYPE_CHECKING, Any, Iterable, Sequence
 
-from airflow.exceptions import AirflowException, RemovedInAirflow3Warning
+from airflow.exceptions import AirflowException
 from airflow.utils.types import NOTSET
 
 if TYPE_CHECKING:
@@ -89,7 +88,7 @@ def update_relative(
         self, other: DependencyMixin, upstream: bool = True, edge_modifier: EdgeModifier | None = None
     ) -> None:
         """
-        Update relationship information about another TaskMixin. Default is no-op.
+        Update relationship information about another DependencyMixin. Default is no-op.
 
         Override if necessary.
         """
@@ -128,22 +127,6 @@ def _iter_references(cls, obj: Any) -> Iterable[tuple[DependencyMixin, str]]:
                 yield from cls._iter_references(o)
 
 
-class TaskMixin(DependencyMixin):
-    """
-    Mixin to provide task-related things.
-
-    :meta private:
-    """
-
-    def __init_subclass__(cls) -> None:
-        warnings.warn(
-            f"TaskMixin has been renamed to DependencyMixin, please update {cls.__name__}",
-            category=RemovedInAirflow3Warning,
-            stacklevel=2,
-        )
-        return super().__init_subclass__()
-
-
 class DAGNode(DependencyMixin, metaclass=ABCMeta):
     """
     A base class for a node in the graph of a workflow.

airflow/models/xcom_arg.py

@@ -135,20 +135,20 @@ def apply_upstream_relationship(op: Operator, arg: Any):
 
     @property
     def roots(self) -> list[DAGNode]:
-        """Required by TaskMixin."""
+        """Required by DependencyMixin."""
         return [op for op, _ in self.iter_references()]
 
     @property
     def leaves(self) -> list[DAGNode]:
-        """Required by TaskMixin."""
+        """Required by DependencyMixin."""
         return [op for op, _ in self.iter_references()]
 
     def set_upstream(
         self,
         task_or_task_list: DependencyMixin | Sequence[DependencyMixin],
         edge_modifier: EdgeModifier | None = None,
     ):
-        """Proxy to underlying operator set_upstream method. Required by TaskMixin."""
+        """Proxy to underlying operator set_upstream method. Required by DependencyMixin."""
         for operator, _ in self.iter_references():
             operator.set_upstream(task_or_task_list, edge_modifier)
 
@@ -157,7 +157,7 @@ def set_downstream(
         task_or_task_list: DependencyMixin | Sequence[DependencyMixin],
         edge_modifier: EdgeModifier | None = None,
     ):
-        """Proxy to underlying operator set_downstream method. Required by TaskMixin."""
+        """Proxy to underlying operator set_downstream method. Required by DependencyMixin."""
         for operator, _ in self.iter_references():
             operator.set_downstream(task_or_task_list, edge_modifier)
 

airflow/utils/task_group.py

@@ -369,12 +369,12 @@ def has_task(self, task: BaseOperator) -> bool:
 
     @property
     def roots(self) -> list[BaseOperator]:
-        """Required by TaskMixin."""
+        """Required by DependencyMixin."""
         return list(self.get_roots())
 
     @property
     def leaves(self) -> list[BaseOperator]:
-        """Required by TaskMixin."""
+        """Required by DependencyMixin."""
         return list(self.get_leaves())
 
     def get_roots(self) -> Generator[BaseOperator, None, None]:

newsfragments/41394.significant.rst

@@ -0,0 +1,6 @@
+**Breaking Change**
+
+The ``airflow.models.taskMixin.TaskMixin`` class has been removed. It was previously
+deprecated in favor of the ``airflow.models.taskMixin.DependencyMixin`` class.
+If your code relies on ``TaskMixin``, please update it to use ``DependencyMixin`` instead
+to ensure compatibility with Airflow 3.0 and beyond.