fix: dispatch underlying op for aliases and decimal literal

`ops.Alias` was added in Ibis recently and the dispatcher was defaulting
to `ops.ValueOp` when it received one -- instead this added in a
specific Alias dispatch rule to pull out the underlying op.

Need to add proper decimal handling, but for now this at least keeps
things consistent between 2.1.1 and 3.x

ibis_substrait/compiler/translate.py

@@ -8,17 +8,20 @@
 import collections
 import collections.abc
 import datetime
+import decimal
 import functools
 import itertools
 import operator
 import uuid
 from typing import Any, Mapping, MutableMapping, Sequence, TypeVar
 
+import ibis
 import ibis.expr.datatypes as dt
 import ibis.expr.operations as ops
 import ibis.expr.schema as sch
 import ibis.expr.types as ir
 from ibis import util
+from packaging import version
 
 from ..proto.substrait import algebra_pb2 as stalg
 from ..proto.substrait import type_pb2 as stt
@@ -264,6 +267,11 @@ def _literal_float64(_: dt.Float64, value: float) -> stalg.Expression.Literal:
     return stalg.Expression.Literal(fp64=value)
 
 
+@translate_literal.register
+def _literal_decimal(_: dt.Decimal, value: decimal.Decimal) -> stalg.Expression.Literal:
+    raise NotImplementedError
+
+
 @translate_literal.register
 def _literal_string(_: dt.String, value: str) -> stalg.Expression.Literal:
     return stalg.Expression.Literal(string=value)
@@ -441,6 +449,19 @@ def _translate_window_bounds(
     return translate_preceding(*preceding), translate_following(*following)
 
 
+if version.parse(ibis.__version__) >= version.parse("3.0.0"):
+
+    @translate.register(ops.Alias)
+    def alias_op(
+        op: ops.Alias,
+        expr: ir.ValueExpr,
+        compiler: SubstraitCompiler,
+        **kwargs: Any,
+    ) -> stalg.Expression:
+        # For an alias, dispatch on the underlying argument
+        return translate(op.arg.op(), op.arg, compiler, **kwargs)
+
+
 @translate.register(ops.ValueOp)
 def value_op(
     op: ops.ValueOp,

ibis_substrait/tests/compiler/test_literal.py

@@ -303,7 +303,7 @@ def test_literal(compiler, expr, ir):
 
 
 @pytest.mark.xfail(
-    raises=ibis.common.exceptions.IbisTypeError,
+    raises=(ibis.common.exceptions.IbisTypeError, NotImplementedError),
     reason="Ibis doesn't allow decimal values through validation",
 )
 def test_decimal_literal(compiler):

pyproject.toml

@@ -23,6 +23,7 @@ python = ">=3.8,<3.11"
 ibis-framework = ">=2,<4"
 protobuf = "^3.19.4"
 platformdirs = "<2.5.2"
+packaging = "^21.3"
 
 [tool.poetry.dev-dependencies]
 black = "^21.9b0"