Remove deprecated ExtContext node (rapidsai#16001)

Polars deprecated with_context in the alpha for version 1, and will remove it for version 1. So let's not bother implementing it. Also add some no-cover pragmas to unreachable code in the translation DSL layer.

Authors:
  - Lawrence Mitchell (https://github.com/wence-)

Approvers:
  - Thomas Li (https://github.com/lithomas1)

URL: rapidsai#16001

python/cudf_polars/cudf_polars/dsl/ir.py

@@ -17,7 +17,7 @@
 import itertools
 import types
 from functools import cache
-from typing import TYPE_CHECKING, Any, Callable, ClassVar, NoReturn
+from typing import TYPE_CHECKING, Any, Callable, ClassVar
 
 import pyarrow as pa
 from typing_extensions import assert_never
@@ -56,7 +56,6 @@
     "MapFunction",
     "Union",
     "HConcat",
-    "ExtContext",
 ]
 
 
@@ -153,7 +152,9 @@ def evaluate(self, *, cache: MutableMapping[int, DataFrame]) -> DataFrame:
             since the translation phase should pick up things that we
             cannot handle.
         """
-        raise NotImplementedError
+        raise NotImplementedError(
+            f"Evaluation of plan {type(self).__name__}"
+        )  # pragma: no cover
 
 
 @dataclasses.dataclass(slots=True)
@@ -346,7 +347,9 @@ class Reduce(IR):
     expr: list[expr.NamedExpr]
     """List of expressions to evaluate to form the new dataframe."""
 
-    def evaluate(self, *, cache: MutableMapping[int, DataFrame]) -> DataFrame:
+    def evaluate(
+        self, *, cache: MutableMapping[int, DataFrame]
+    ) -> DataFrame:  # pragma: no cover; polars doesn't emit this node yet
         """Evaluate and return a dataframe."""
         df = self.df.evaluate(cache=cache)
         columns = broadcast(*(e.evaluate(df) for e in self.expr))
@@ -938,23 +941,3 @@ def evaluate(self, *, cache: MutableMapping[int, DataFrame]) -> DataFrame:
         return DataFrame(
             list(itertools.chain.from_iterable(df.columns for df in dfs)),
         )
-
-
-@dataclasses.dataclass(slots=True)
-class ExtContext(IR):
-    """
-    Concatenate dataframes horizontally.
-
-    Prefer HConcat, since this is going to be deprecated on the polars side.
-    """
-
-    df: IR
-    """Input."""
-    extra: list[IR]
-    """List of extra inputs."""
-
-    def __post_init__(self) -> NoReturn:
-        """Validate preconditions."""
-        raise NotImplementedError(
-            "ExtContext will be deprecated, use horizontal concat instead."
-        )

python/cudf_polars/cudf_polars/dsl/translate.py

@@ -63,7 +63,9 @@ def __exit__(self, *args: Any) -> None:
 def _translate_ir(
     node: Any, visitor: NodeTraverser, schema: dict[str, plc.DataType]
 ) -> ir.IR:
-    raise NotImplementedError(f"Translation for {type(node).__name__}")
+    raise NotImplementedError(
+        f"Translation for {type(node).__name__}"
+    )  # pragma: no cover
 
 
 @_translate_ir.register
@@ -172,7 +174,7 @@ def _(
 @_translate_ir.register
 def _(
     node: pl_ir.Reduce, visitor: NodeTraverser, schema: dict[str, plc.DataType]
-) -> ir.IR:
+) -> ir.IR:  # pragma: no cover; polars doesn't emit this node yet
     with set_node(visitor, node.input):
         inp = translate_ir(visitor, n=None)
         exprs = [translate_named_expr(visitor, n=e) for e in node.expr]
@@ -256,17 +258,6 @@ def _(
     return ir.HConcat(schema, [translate_ir(visitor, n=n) for n in node.inputs])
 
 
-@_translate_ir.register
-def _(
-    node: pl_ir.ExtContext, visitor: NodeTraverser, schema: dict[str, plc.DataType]
-) -> ir.IR:
-    return ir.ExtContext(
-        schema,
-        translate_ir(visitor, n=node.input),
-        [translate_ir(visitor, n=n) for n in node.contexts],
-    )
-
-
 def translate_ir(visitor: NodeTraverser, *, n: int | None = None) -> ir.IR:
     """
     Translate a polars-internal IR node to our representation.
@@ -333,7 +324,9 @@ def translate_named_expr(
 def _translate_expr(
     node: Any, visitor: NodeTraverser, dtype: plc.DataType
 ) -> expr.Expr:
-    raise NotImplementedError(f"Translation for {type(node).__name__}")
+    raise NotImplementedError(
+        f"Translation for {type(node).__name__}"
+    )  # pragma: no cover
 
 
 @_translate_expr.register