Ibis check backend (#1831)

* [wip] add minimal ibis check backend implementation

Signed-off-by: cosmicBboy <[email protected]>

* support scalar, column, and table check output types

Signed-off-by: cosmicBboy <[email protected]>

* support scalar, column, and table check output types

Signed-off-by: cosmicBboy <[email protected]>

* Ibis check backend suggestions (#1855)

* Apply suggestions from code review

Signed-off-by: Deepyaman Datta <[email protected]>

* Fix row-order-dependent order by adding table cols

Signed-off-by: Deepyaman Datta <[email protected]>

---------

Signed-off-by: Deepyaman Datta <[email protected]>

* fix lint

Signed-off-by: cosmicBboy <[email protected]>

* fix unit tests

Signed-off-by: cosmicBboy <[email protected]>

---------

Signed-off-by: cosmicBboy <[email protected]>
Signed-off-by: Deepyaman Datta <[email protected]>
Co-authored-by: Deepyaman Datta <[email protected]>

pandera/api/ibis/types.py

@@ -1,11 +1,16 @@
 """Ibis types."""
 
-from typing import NamedTuple, Union
+from typing import NamedTuple, Optional, Union
 
 import ibis.expr.datatypes as dt
 import ibis.expr.types as ir
 
 
+class IbisData(NamedTuple):
+    table: ir.Table
+    key: Optional[str] = None
+
+
 class CheckResult(NamedTuple):
     """Check result for user-defined checks."""
 
@@ -15,6 +20,8 @@ class CheckResult(NamedTuple):
     failure_cases: ir.Table
 
 
+IbisCheckObjects = Union[ir.Table, ir.Column]
+
 IbisDtypeInputTypes = Union[
     str,
     type,

pandera/backends/ibis/checks.py

@@ -0,0 +1,160 @@
+"""Check backend for Ibis."""
+
+from functools import partial
+from typing import Optional
+
+
+import ibis
+import ibis.expr.types as ir
+from ibis import _, selectors as s
+from ibis.expr.types.groupby import GroupedTable
+from multimethod import overload
+
+from pandera.api.base.checks import CheckResult
+from pandera.api.checks import Check
+from pandera.api.ibis.types import IbisData
+from pandera.backends.base import BaseCheckBackend
+from pandera.backends.ibis.utils import select_column
+from pandera.constants import CHECK_OUTPUT_KEY
+
+CHECK_OUTPUT_SUFFIX = f"__{CHECK_OUTPUT_KEY}__"
+
+
+class IbisCheckBackend(BaseCheckBackend):
+    """Check backend for Ibis."""
+
+    def __init__(self, check: Check):
+        """Initializes a check backend object."""
+        super().__init__(check)
+        assert check._check_fn is not None, "Check._check_fn must be set."
+        self.check = check
+        self.check_fn = partial(check._check_fn, **check._check_kwargs)
+
+    def groupby(self, check_obj) -> GroupedTable:
+        """Implements groupby behavior for check object."""
+        raise NotImplementedError
+
+    def query(self, check_obj: ir.Table):
+        """Implements querying behavior to produce subset of check object."""
+        raise NotImplementedError
+
+    def aggregate(self, check_obj: ir.Table):
+        """Implements aggregation behavior for check object."""
+        raise NotImplementedError
+
+    def preprocess(self, check_obj: ir.Table, key: Optional[str]):
+        """Preprocesses a check object before applying the check function."""
+        # This handles the case of Series validation, which has no other context except
+        # for the index to groupby on. Right now grouping by the index is not allowed.
+        return check_obj
+
+    def apply(self, check_obj: IbisData):
+        """Apply the check function to a check object."""
+        if self.check.element_wise:
+            selector = (
+                select_column(check_obj.key)
+                if check_obj.key is not None
+                else s.all()
+            )
+            out = check_obj.table.mutate(
+                s.across(
+                    selector, self.check_fn, f"{{col}}{CHECK_OUTPUT_SUFFIX}"
+                )
+            ).select(selector | s.endswith(CHECK_OUTPUT_SUFFIX))
+        else:
+            out = self.check_fn(check_obj)
+            if isinstance(out, dict):
+                out = check_obj.table.mutate(
+                    **{f"{k}{CHECK_OUTPUT_SUFFIX}": v for k, v in out.items()}
+                )
+
+        if isinstance(out, ir.Table):
+            # for checks that return a boolean dataframe, make sure all columns
+            # are boolean and reduce to a single boolean column.
+            acc = ibis.literal(True)
+            for col in out.columns:
+                if col.endswith(CHECK_OUTPUT_SUFFIX):
+                    assert out[col].type().is_boolean(), (
+                        f"column '{col[: -len(CHECK_OUTPUT_SUFFIX)]}' "
+                        "is not boolean. If check function returns a "
+                        "dataframe, it must contain only boolean columns."
+                    )
+                    acc = acc & out[col]
+            return out.mutate({CHECK_OUTPUT_KEY: acc})
+        elif out.type().is_boolean():
+            return out
+        else:
+            raise TypeError(  # pragma: no cover
+                f"output type of check_fn not recognized: {type(out)}"
+            )
+
+    @overload
+    def postprocess(self, check_obj, check_output):
+        """Postprocesses the result of applying the check function."""
+        raise TypeError(  # pragma: no cover
+            f"output type of check_fn not recognized: {type(check_output)}"
+        )
+
+    @overload  # type: ignore [no-redef]
+    def postprocess(
+        self,
+        check_obj: IbisData,
+        check_output: ir.BooleanScalar,
+    ) -> CheckResult:
+        """Postprocesses the result of applying the check function."""
+        return CheckResult(
+            check_output=check_output,
+            check_passed=check_output,
+            checked_object=check_obj,
+            failure_cases=None,
+        )
+
+    @overload  # type: ignore [no-redef]
+    def postprocess(
+        self,
+        check_obj: IbisData,
+        check_output: ir.BooleanColumn,
+    ) -> CheckResult:
+        """Postprocesses the result of applying the check function."""
+        check_output = check_output.name(CHECK_OUTPUT_KEY)
+        failure_cases = check_obj.table.filter(~check_output)
+        if check_obj.key is not None:
+            failure_cases = failure_cases.select(check_obj.key)
+        return CheckResult(
+            check_output=check_output,
+            check_passed=check_output.all(),
+            checked_object=check_obj,
+            failure_cases=failure_cases,
+        )
+
+    @overload  # type: ignore [no-redef]
+    def postprocess(
+        self,
+        check_obj: IbisData,
+        check_output: ir.Table,
+    ) -> CheckResult:
+        """Postprocesses the result of applying the check function."""
+        passed = check_output[CHECK_OUTPUT_KEY].all()
+        failure_cases = check_output.filter(~_[CHECK_OUTPUT_KEY]).drop(
+            s.endswith(f"__{CHECK_OUTPUT_KEY}__")
+            | select_column(CHECK_OUTPUT_KEY)
+        )
+
+        if check_obj.key is not None:
+            failure_cases = failure_cases.select(check_obj.key)
+        return CheckResult(
+            check_output=check_output.select(CHECK_OUTPUT_KEY),
+            check_passed=passed,
+            checked_object=check_obj,
+            failure_cases=failure_cases,
+        )
+
+    def __call__(
+        self,
+        check_obj: ir.Table,
+        key: Optional[str] = None,
+    ) -> CheckResult:
+        check_obj = self.preprocess(check_obj, key)
+        ibis_data = IbisData(check_obj, key)
+        check_output = self.apply(ibis_data)
+        return self.postprocess(ibis_data, check_output)

pandera/backends/ibis/components.py

@@ -42,10 +42,12 @@ def validate(
 
         # run the checks
         core_checks = [
-            (self.check_dtype, (sample, schema)),
+            self.check_dtype,
+            self.run_checks,
         ]
 
-        for check, args in core_checks:
+        args = (sample, schema)
+        for check in core_checks:
             results = check(*args)
             if isinstance(results, CoreCheckResult):
                 results = [results]
@@ -114,3 +116,34 @@ def check_dtype(
             message=msg,
             failure_cases=failure_cases,
         )
+
+    @validate_scope(scope=ValidationScope.DATA)
+    def run_checks(self, check_obj, schema) -> List[CoreCheckResult]:
+        check_results: List[CoreCheckResult] = []
+        for check_index, check in enumerate(schema.checks):
+            try:
+                check_results.append(
+                    self.run_check(
+                        check_obj,
+                        schema,
+                        check,
+                        check_index,
+                        schema.selector,
+                    )
+                )
+            except Exception as err:  # pylint: disable=broad-except
+                # catch other exceptions that may occur when executing the Check
+                err_msg = f'"{err.args[0]}"' if len(err.args) > 0 else ""
+                msg = f"{err.__class__.__name__}({err_msg})"
+                check_results.append(
+                    CoreCheckResult(
+                        passed=False,
+                        check=check,
+                        check_index=check_index,
+                        reason_code=SchemaErrorReason.CHECK_ERROR,
+                        message=msg,
+                        failure_cases=msg,
+                        original_exc=err,
+                    )
+                )
+        return check_results

pandera/backends/ibis/register.py

@@ -16,6 +16,8 @@ def register_ibis_backends():
     from pandera.api.ibis.container import DataFrameSchema
     from pandera.backends.ibis.components import ColumnBackend
     from pandera.backends.ibis.container import DataFrameSchemaBackend
+    from pandera.backends.ibis.checks import IbisCheckBackend
 
     DataFrameSchema.register_backend(ir.Table, DataFrameSchemaBackend)
     Column.register_backend(ir.Table, ColumnBackend)
+    Check.register_backend(ir.Table, IbisCheckBackend)

pandera/backends/ibis/utils.py

@@ -0,0 +1,10 @@
+"""Utility functions for the Ibis backend."""
+
+from ibis import selectors as s
+
+
+def select_column(*names):
+    """Select a column from a table."""
+    if hasattr(s, "cols"):
+        return s.cols(*names)
+    return s.c(*names)

pandera/backends/pandas/checks.py

@@ -18,7 +18,7 @@
 
 
 class PandasCheckBackend(BaseCheckBackend):
-    """Check backend ofr pandas."""
+    """Check backend for pandas."""
 
     def __init__(self, check: Check):
         """Initializes a check backend object."""

pandera/backends/polars/checks.py

@@ -1,4 +1,4 @@
-"""Check backend for pandas."""
+"""Check backend for polars."""
 
 from functools import partial
 from typing import Optional
@@ -19,7 +19,7 @@
 
 
 class PolarsCheckBackend(BaseCheckBackend):
-    """Check backend ofr pandas."""
+    """Check backend for polars."""
 
     def __init__(self, check: Check):
         """Initializes a check backend object."""

pandera/ibis.py

@@ -6,3 +6,4 @@
 from pandera.api.ibis.components import Column
 from pandera.api.ibis.container import DataFrameSchema
 from pandera.api.ibis.model import DataFrameModel
+from pandera.api.ibis.types import IbisData