fix(ir): ensure that operation nodes and expressions are slotted

ibis/backends/polars/rewrites.py

@@ -1,12 +1,11 @@
 from __future__ import annotations
 
+from koerce import attribute, replace
 from public import public
 
 import ibis.expr.datatypes as dt
 import ibis.expr.operations as ops
-from ibis.common.annotations import attribute
 from ibis.common.collections import FrozenDict
-from ibis.common.patterns import replace
 from ibis.common.typing import VarTuple  # noqa: TCH001
 from ibis.expr.schema import Schema
 

ibis/backends/tests/test_temporal.py

@@ -37,8 +37,8 @@
     SnowflakeProgrammingError,
     TrinoUserError,
 )
-from ibis.conftest import IS_SPARK_REMOTE
 from ibis.common.grounds import ValidationError
+from ibis.conftest import IS_SPARK_REMOTE
 
 np = pytest.importorskip("numpy")
 pd = pytest.importorskip("pandas")

ibis/expr/datatypes/core.py

@@ -462,15 +462,15 @@ def is_variadic(self) -> bool:
 
 
 @public
-class Unknown(DataType):
+class Unknown(DataType, singleton=True):
     """An unknown type."""
 
     scalar = "UnknownScalar"
     column = "UnknownColumn"
 
 
 @public
-class Primitive(DataType):
+class Primitive(DataType, singleton=True):
     """Values with known size."""
 
 
@@ -531,7 +531,7 @@ def nbytes(self) -> int:
 
 
 @public
-class String(Variadic):
+class String(Variadic, singleton=True):
     """A type representing a string.
 
     Notes
@@ -546,7 +546,7 @@ class String(Variadic):
 
 
 @public
-class Binary(Variadic):
+class Binary(Variadic, singleton=True):
     """A type representing a sequence of bytes.
 
     Notes

ibis/expr/datatypes/tests/test_core.py

@@ -432,20 +432,29 @@ def test_struct_equality():
     assert st3 != st2
 
 
-def test_booleqn_equality():
+def test_singleton_datatypes():
+    assert dt.null is dt.Null()
+    assert dt.unknown is dt.Unknown()
+    assert dt.boolean is dt.Boolean()
+    assert dt.string is dt.String()
+    assert dt.binary is dt.Binary()
+
+
+def test_singleton_boolean():
     assert dt.Boolean() == dt.boolean
-    assert dt.Boolean() == dt.Boolean()
-    assert dt.Boolean(nullable=True) == dt.boolean
-    assert dt.Boolean(nullable=False) != dt.boolean
-    assert dt.Boolean(nullable=False) == dt.Boolean(nullable=False)
-    assert dt.Boolean(nullable=True) == dt.Boolean(nullable=True)
-    assert dt.Boolean(nullable=True) != dt.Boolean(nullable=False)
-
-
-def test_primite_equality():
-    assert dt.Int64() == dt.int64
-    assert dt.Int64(nullable=False) != dt.int64
-    assert dt.Int64(nullable=False) == dt.Int64(nullable=False)
+    assert dt.Boolean() is dt.boolean
+    assert dt.Boolean() is dt.Boolean()
+    assert dt.Boolean(nullable=True) is dt.boolean
+    assert dt.Boolean(nullable=False) is not dt.boolean
+    assert dt.Boolean(nullable=False) is dt.Boolean(nullable=False)
+    assert dt.Boolean(nullable=True) is dt.Boolean(nullable=True)
+    assert dt.Boolean(nullable=True) is not dt.Boolean(nullable=False)
+
+
+def test_singleton_primitive():
+    assert dt.Int64() is dt.int64
+    assert dt.Int64(nullable=False) is not dt.int64
+    assert dt.Int64(nullable=False) is dt.Int64(nullable=False)
 
 
 def test_array_type_not_equals():

ibis/expr/operations/generic.py

@@ -175,7 +175,7 @@ def name(self):
 
 
 @public
-class Constant(Scalar):
+class Constant(Scalar, singleton=True):
     """A function that produces a constant."""
 
     shape = ds.scalar

ibis/expr/operations/reductions.py

@@ -380,7 +380,7 @@ class ArrayCollect(Filterable, Reduction):
 
     def __init__(self, arg, order_by, distinct, **kwargs):
         if distinct and order_by and [arg] != [key.expr for key in order_by]:
-            raise ValidationError(
+            raise ValueError(
                 "`collect` with `order_by` and `distinct=True` and may only "
                 "order by the collected column"
             )

ibis/expr/operations/relations.py

@@ -378,6 +378,8 @@ class Difference(Set):
 class PhysicalTable(Relation):
     """Base class for tables with a name."""
 
+    __slots__ = ("__weakref__",)
+
     name: str
     values = FrozenOrderedDict()
 

ibis/expr/tests/test_reductions.py

@@ -8,6 +8,7 @@
 import ibis.expr.operations as ops
 from ibis import _
 from ibis.common.exceptions import IbisTypeError
+from ibis.common.grounds import ValidationError
 
 
 @pytest.mark.parametrize(

ibis/expr/types/core.py

@@ -5,7 +5,7 @@
 import webbrowser
 from typing import TYPE_CHECKING, Any, NoReturn
 
-from koerce import MatchError
+from koerce import Immutable, MatchError
 from public import public
 
 import ibis
@@ -38,11 +38,15 @@
 
     class _FixedTextJupyterMixin:
         """No-op when rich is not installed."""
+
+        __slots__ = ()
 else:
 
     class _FixedTextJupyterMixin(JupyterMixin):
         """JupyterMixin adds a spurious newline to text, this fixes the issue."""
 
+        __slots__ = ()
+
         def _repr_mimebundle_(self, *args, **kwargs):
             try:
                 bundle = super()._repr_mimebundle_(*args, **kwargs)
@@ -63,7 +67,7 @@ def _capture_rich_renderable(renderable: RenderableType) -> str:
 
 
 @public
-class Expr:
+class Expr(Immutable):
     """Base expression class."""
 
     __slots__ = ("_arg",)

ibis/expr/types/generic.py

@@ -2493,6 +2493,9 @@ class NullColumn(Column, NullValue):
     pass
 
 
+_THE_NULL = None
+
+
 @public
 @deferrable
 def null(type: dt.DataType | str | None = None) -> Value:
@@ -2516,8 +2519,11 @@ def null(type: dt.DataType | str | None = None) -> Value:
     │ True │
     └──────┘
     """
+    global _THE_NULL  # noqa: PLW0603
     if type is None:
-        type = dt.null
+        if _THE_NULL is None:
+            _THE_NULL = ops.Literal(None, dt.null).to_expr()
+        return _THE_NULL
     return ops.Literal(None, type).to_expr()
 
 

ibis/tests/expr/test_value_exprs.py

@@ -1735,3 +1735,21 @@ def test_value_fillna_depr_warn():
     t = ibis.table({"a": "int", "b": "str"})
     with pytest.warns(FutureWarning, match="v9.1"):
         t.b.fillna("missing")
+
+
+def assert_slotted(obj):
+    assert hasattr(obj, "__slots__")
+    assert not hasattr(obj, "__dict__")
+
+
+def test_that_value_expressions_are_slotted():
+    t = ibis.table({"a": "int", "b": "str"})
+    exprs = [
+        t.a,
+        t.b,
+        t.a + 1,
+        t,
+    ]
+    for expr in exprs:
+        assert_slotted(expr)
+        assert_slotted(expr.op())