compat: Dask 2025.1 (#6494)

holoviews/tests/core/data/test_daskinterface.py

@@ -13,13 +13,10 @@
 from holoviews.core.util import PANDAS_VERSION
 from holoviews.util.transform import dim
 
-from ...utils import dask_switcher
+from ...utils import DASK_VERSION, dask_setup, dask_switcher
 from .test_pandasinterface import BasePandasInterfaceTests
 
-try:
-    import dask_expr
-except ImportError:
-    dask_expr = None
+classic, expr = dask_setup()
 
 
 class _DaskDatasetTest(BasePandasInterfaceTests):
@@ -136,9 +133,11 @@ def test_select_expression_lazy(self):
 
 class DaskClassicDatasetTest(_DaskDatasetTest):
 
-    data_type = dd.core.DataFrame
+    # No longer supported from Dask 2025.1
 
-    __test__ = True
+    data_type = getattr(dd.core, "DataFrame", None)
+
+    __test__ = classic
 
     @dask_switcher(query=False)
     def setUp(self):
@@ -147,11 +146,17 @@ def setUp(self):
 
 class DaskExprDatasetTest(_DaskDatasetTest):
 
-    __test__ = bool(dask_expr)
+    __test__ = expr
 
     @property
     def data_type(self):
-        return dask_expr.DataFrame
+        # Only available from 2025.1 and forward
+        if DASK_VERSION >= (2025, 1, 0):
+            return dd.DataFrame
+        else:
+            import dask_expr
+
+            return dask_expr.DataFrame
 
     @dask_switcher(query=True)
     def setUp(self):

holoviews/tests/utils.py

@@ -1,13 +1,15 @@
 import logging
 import os
 import sys
-from contextlib import contextmanager
+from contextlib import contextmanager, suppress
+from functools import lru_cache
 from importlib import reload
 from importlib.util import find_spec
 
 import param
 import pytest
 
+from holoviews.core.util import _no_import_version
 from holoviews.element.comparison import ComparisonTestCase
 
 cwd = os.path.abspath(os.path.split(__file__)[0])
@@ -118,25 +120,61 @@ def tearDown(self):
 
 
 DASK_UNAVAILABLE = find_spec("dask") is None
-EXPR_UNAVAILABLE = find_spec("dask_expr") is None
+DASK_VERSION = _no_import_version("dask")
+
+
+@lru_cache
+def dask_setup():
+    """
+    Set-up both dask dataframes, using lru_cahce to only do it once
+
+    """
+    from datashader.data_libraries.dask import bypixel, dask_pipeline
+
+    classic, expr = False, False
+
+    # Removed in Dask 2025.1, and will raise AttributeError
+    if DASK_VERSION < (2025, 1, 0):
+        import dask.dataframe as dd
+
+        bypixel.pipeline.register(dd.core.DataFrame)(dask_pipeline)
+        classic = True
+    else:
+        # dask_expr import below will now fail with:
+        # cannot import name '_Frame' from 'dask.dataframe.core'
+        expr = True
+
+    with suppress(ImportError):
+        import dask_expr
+
+        bypixel.pipeline.register(dask_expr.DataFrame)(dask_pipeline)
+        expr = True
+
+    return classic, expr
 
 
 @contextmanager
-def dask_switcher(*, query=False, extras=()):
+def dask_switcher(*, query=False, extras=None):
     """
     Context manager to switch on/off dask-expr query planning.
+
     Using a context manager as it is an easy way to
     change the function to a decorator.
     """
     if DASK_UNAVAILABLE:
         pytest.skip("dask is not available")
-    if query and EXPR_UNAVAILABLE:
+
+    classic, expr = dask_setup()
+
+    if not query and not classic:
+        pytest.skip("Classic DataFrame no longer supported by dask")
+    if query and not expr:
         pytest.skip("dask-expr is not available")
 
     import dask
 
     dask.config.set(**{"dataframe.query-planning": query})
-    for module in ("dask.dataframe", *extras):
+    for module in ("dask.dataframe", *(extras or ())):
         if module in sys.modules:
             reload(sys.modules[module])
     yield

pixi.toml

@@ -158,7 +158,7 @@ pytest-xdist = "*"
 test-unit = 'pytest holoviews/tests -n logical --dist loadgroup'
 
 [feature.test-example.tasks]
-test-example = { cmd = 'pytest -n logical --dist loadscope --nbval-lax examples', env = { DASK_DATAFRAME__QUERY_PLANNING = "False" } }
+test-example = 'pytest -n logical --dist loadscope --nbval-lax examples'
 
 [feature.test-example.dependencies]
 nbval = "*"
@@ -206,7 +206,6 @@ python-kaleido = "*"
 selenium = "*"
 
 [feature.doc.activation.env]
-DASK_DATAFRAME__QUERY_PLANNING = "False"
 MOZ_HEADLESS = "1"
 MPLBACKEND = "Agg"
 PANEL_EMBED = "true"