fix: relax dask version requirement and use a better check for Task

pyproject.toml

@@ -37,8 +37,7 @@ classifiers = [
 ]
 dependencies = [
   "awkward >=2.5.1",
-  "dask >=2024.12.0;python_version>'3.9'",
-  "dask >=2023.04.0;python_version<'3.10'",
+  "dask >=2023.04.0",
   "cachetools",
   "typing_extensions >=4.8.0",
 ]

src/dask_awkward/layers/layers.py

@@ -5,18 +5,17 @@
 from typing import TYPE_CHECKING, Any, Literal, Protocol, TypeVar, Union, cast
 
 import dask
-
-_dask_uses_tasks = hasattr(dask, "_task_spec")
-
 from dask.blockwise import Blockwise, BlockwiseDepDict, blockwise_token
 from dask.highlevelgraph import MaterializedLayer
 from dask.layers import DataFrameTreeReduction
 from typing_extensions import TypeAlias
 
 from dask_awkward.utils import LazyInputsDict
 
+_dask_uses_tasks = hasattr(dask.blockwise, "Task")
+
 if _dask_uses_tasks:
-    from dask._task_spec import Task, TaskRef
+    from dask.blockwise import Task, TaskRef  # type: ignore
 
 if TYPE_CHECKING:
     from awkward import Array as AwkwardArray

src/dask_awkward/lib/core.py

@@ -62,7 +62,7 @@
 )
 
 if _dask_uses_tasks:
-    from dask._task_spec import TaskRef
+    from dask.blockwise import TaskRef  # type: ignore
 
 if TYPE_CHECKING:
     from awkward.contents.content import Content

src/dask_awkward/lib/optimize.py

@@ -22,7 +22,7 @@
 from dask_awkward.utils import first
 
 if _dask_uses_tasks:
-    from dask._task_spec import GraphNode, Task, TaskRef
+    from dask.blockwise import GraphNode, Task, TaskRef  # type: ignore
 
 if TYPE_CHECKING:
     from awkward._nplikes.typetracer import TypeTracerReport