chore: refactor IsNullOp and NotNullOp logic to make scalar ops generation easier

bigframes/core/array_value.py

@@ -37,10 +37,10 @@
 from bigframes.core.window_spec import WindowSpec
 import bigframes.dtypes
 import bigframes.exceptions as bfe
-import bigframes.operations as ops
-import bigframes.operations.aggregations as agg_ops
 
 if typing.TYPE_CHECKING:
+    # Avoid circular imports.
+    import bigframes.operations.aggregations as agg_ops
     from bigframes.session import Session
 
 ORDER_ID_COLUMN = "bigframes_ordering_id"
@@ -185,6 +185,8 @@ def get_column_type(self, key: str) -> bigframes.dtypes.Dtype:
 
     def row_count(self) -> ArrayValue:
         """Get number of rows in ArrayValue as a single-entry ArrayValue."""
+        import bigframes.operations.aggregations as agg_ops  # Avoid circular imports.
+
         return ArrayValue(
             nodes.AggregateNode(
                 child=self.node,
@@ -200,6 +202,8 @@ def row_count(self) -> ArrayValue:
     # Operations
     def filter_by_id(self, predicate_id: str, keep_null: bool = False) -> ArrayValue:
         """Filter the table on a given expression, the predicate must be a boolean series aligned with the table expression."""
+        import bigframes.operations as ops  # Avoid circular imports.
+
         predicate: ex.Expression = ex.deref(predicate_id)
         if keep_null:
             predicate = ops.fillna_op.as_expr(predicate, ex.const(True))

bigframes/core/compile/compiled.py

@@ -34,7 +34,6 @@
 import bigframes.core.compile.googlesql
 import bigframes.core.compile.ibis_types
 import bigframes.core.compile.scalar_op_compiler as op_compilers
-import bigframes.core.compile.scalar_op_compiler as scalar_op_compiler
 import bigframes.core.expression as ex
 from bigframes.core.ordering import OrderingExpression
 import bigframes.core.sql
@@ -45,6 +44,12 @@
 op_compiler = op_compilers.scalar_op_compiler
 
 
+# This must be the last import. Currently depending on side-effects.
+# TODO(tswast): Refactor all ops to register in the same file as where they are
+# defined so we don't need this.
+import bigframes.core.compile.scalar_op_registry  # noqa: F401,E402
+
+
 # Ibis Implementations
 class UnorderedIR:
     def __init__(
@@ -679,13 +684,15 @@ def _join_condition(
 
 
 def _as_groupable(value: ibis_types.Value):
+    from bigframes.core.compile import scalar_op_registry
+
     # Some types need to be converted to another type to enable groupby
     if value.type().is_float64():
         return value.cast(ibis_dtypes.str)
     elif value.type().is_geospatial():
         return typing.cast(ibis_types.GeoSpatialColumn, value).as_binary()
     elif value.type().is_json():
-        return scalar_op_compiler.to_json_string(value)
+        return scalar_op_registry.to_json_string(value)
     else:
         return value
 

bigframes/core/compile/compiler.py

@@ -29,7 +29,6 @@
 import bigframes.core.compile.concat as concat_impl
 import bigframes.core.compile.configs as configs
 import bigframes.core.compile.explode
-import bigframes.core.compile.scalar_op_compiler as compile_scalar
 import bigframes.core.nodes as nodes
 import bigframes.core.ordering as bf_ordering
 import bigframes.core.rewrite as rewrites
@@ -178,6 +177,8 @@ def compile_readlocal(node: nodes.ReadLocalNode, *args):
 
 @_compile_node.register
 def compile_readtable(node: nodes.ReadTableNode, *args):
+    from bigframes.core.compile import scalar_op_registry
+
     ibis_table = _table_to_ibis(
         node.source, scan_cols=[col.source_id for col in node.scan_list.items]
     )
@@ -188,7 +189,7 @@ def compile_readtable(node: nodes.ReadTableNode, *args):
             scan_item.dtype == dtypes.JSON_DTYPE
             and ibis_table[scan_item.source_id].type() == ibis_dtypes.string
         ):
-            json_column = compile_scalar.parse_json(
+            json_column = scalar_op_registry.parse_json(
                 ibis_table[scan_item.source_id]
             ).name(scan_item.source_id)
             ibis_table = ibis_table.mutate(json_column)