Copilot commented on code in PR #69575:
URL: https://github.com/apache/airflow/pull/69575#discussion_r3567854636


##########
providers/common/dataquality/src/airflow/providers/common/dataquality/backends/object_storage.py:
##########
@@ -0,0 +1,250 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+"""
+Object-storage results backend.
+
+Each DQ check writes a keyed JSON document plus read indexes optimized for the 
UI:
+
+    runs/by_task/dag_id=<dag>/task_id=<task>/date=<2026-07-04>/<run_uid>.json
+        Canonical run record: ``{"run": ..., "results": [...], "summary": 
...}``.
+
+    
runs/by_task_instance/dag_id=<dag>/task_id=<task>/<safe_run_id>__<map_index>.json
+        Latest result for a task-instance page. Last write wins across retries.
+
+    
rules/by_task_rule/dag_id=<dag>/task_id=<task>/rule_uid=<uid>/<started_at>__<run_uid>.json
+        One rule result plus run context: ``{"run": ..., "result": ...}``.
+
+The duplicate files are intentional read indexes: DQ tasks write once, while 
the UI reads
+many times. Keeping these indexes avoids scanning all task runs for common UI 
views.
+"""
+
+from __future__ import annotations
+
+import json
+import logging
+from datetime import datetime, timezone
+from typing import Any
+
+from airflow.providers.common.dataquality.results import DQRun, RuleResult, 
build_summary
+from airflow.sdk import ObjectStoragePath
+
+log = logging.getLogger(__name__)
+
+
+class ObjectStorageResultsBackend:
+    """Persist DQ results as JSON files via ``ObjectStoragePath``."""
+
+    def __init__(self, results_path: str, conn_id: str | None = None) -> None:
+        self.root = ObjectStoragePath(results_path, conn_id=conn_id)
+
+    def write_run(self, run: DQRun, results: list[RuleResult]) -> None:
+        timestamp = run.started_at or datetime.now(tz=timezone.utc).isoformat()
+        payload = self._build_run_payload(run, results)
+
+        self._write_run_file(run, timestamp[:10], payload)
+        self._write_task_instance_index(run, payload)
+        self._write_rule_indexes(run, results, timestamp)
+
+    def read_task_rule_history(
+        self, dag_id: str, task_id: str, rule_uid: str, limit: int = 100, 
before: str | None = None
+    ) -> dict[str, Any]:
+        """Return recent results for one rule produced by one task, newest 
first."""
+        rule_dir = (
+            self.root
+            / "rules"
+            / "by_task_rule"
+            / f"dag_id={dag_id}"
+            / f"task_id={task_id}"
+            / f"rule_uid={rule_uid}"
+        )
+        return self._read_rule_history_dir(rule_dir, limit, before)
+
+    def read_task_runs(
+        self, dag_id: str, task_id: str, limit: int = 50, before: str | None = 
None
+    ) -> dict[str, Any]:
+        """
+        Return recent data quality runs for one task, newest first.
+
+        Returns ``{"items": [...], "next_cursor": ...}``. ``before`` is the 
opaque
+        ``next_cursor`` from the previous page, so "load more" only reads runs 
it hasn't
+        shown yet. ``next_cursor`` is set by reading one extra entry past 
``limit``: cheap
+        on every page except the last one, where there's no way to confirm 
history is
+        exhausted without walking to the end.
+
+        ``date=`` partition names sort correctly as plain strings, so 
directories are walked
+        newest-first and scanning stops as soon as ``limit + 1`` matching runs 
have been
+        collected — a task with years of history doesn't pay for a full scan 
on every page.
+        """
+        task_dir = self.root / "runs" / "by_task" / f"dag_id={dag_id}" / 
f"task_id={task_id}"
+        if not task_dir.exists():
+            return {"items": [], "next_cursor": None}
+
+        date_dirs = sorted((path for path in task_dir.iterdir() if 
path.is_dir()), reverse=True)
+        runs = []
+        for date_dir in date_dirs:
+            for path in date_dir.iterdir():
+                if not path.name.endswith(".json"):
+                    continue
+                payload = self._read_json(path)
+                if payload is None:
+                    continue
+                cursor = self._get_run_payload_cursor(payload)
+                if before is not None and cursor >= before:
+                    continue
+                runs.append(payload)
+            if len(runs) > limit:
+                break

Review Comment:
   `read_task_runs()` reads *every* JSON file in the newest `date=` directory 
before checking `limit`, which can be very expensive for tasks with lots of 
history in a single day. Consider stopping the inner loop as soon as `limit + 
1` items are collected so pagination avoids unnecessary object-store 
listings/reads.



##########
providers/common/dataquality/src/airflow/providers/common/dataquality/operators/dq_check.py:
##########
@@ -0,0 +1,255 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+from __future__ import annotations
+
+import logging
+from collections.abc import Sequence
+from datetime import datetime, timezone
+from typing import TYPE_CHECKING, Any, cast
+
+from airflow.providers.common.dataquality.assets import DQ_RESULT_EXTRA_KEY, 
get_asset_quality_config
+from airflow.providers.common.dataquality.backends import 
get_backend_from_config
+from airflow.providers.common.dataquality.engines.sql import SQLDQEngine
+from airflow.providers.common.dataquality.exceptions import DQCheckFailedError
+from airflow.providers.common.dataquality.results import (
+    ERROR,
+    FAIL,
+    PASS,
+    WARN,
+    DQRun,
+    RuleResult,
+    build_summary,
+)
+from airflow.providers.common.dataquality.rules import RuleSet, describe_rule
+from airflow.providers.common.sql.operators.sql import BaseSQLOperator
+from airflow.sdk.definitions._internal.types import SET_DURING_EXECUTION
+
+if TYPE_CHECKING:
+    from airflow.providers.common.dataquality.engines.sql import Observation
+    from airflow.providers.common.dataquality.rules.rule import Condition, 
Dimension
+    from airflow.providers.common.sql.hooks.sql import DbApiHook
+    from airflow.sdk import Asset, Context
+
+log = logging.getLogger(__name__)
+
+FAIL_ON_CHOICES = ("error", "warn", "never")
+
+
+class DQCheckOperator(BaseSQLOperator):
+    """
+    Run a ruleset against a table and persist per-rule results to the 
configured results store.
+
+    Every rule is evaluated and recorded regardless of the task outcome. 
Execution errors
+    (a check query failing) always fail the task; rule failures fail the task 
according to
+    ``fail_on``.
+
+    :param ruleset: A 
:class:`~airflow.providers.common.dataquality.rules.RuleSet`, its dict form, or 
a path
+        to a YAML ruleset file. Optional when ``asset`` carries one.
+    :param table: The table to run checks against. Optional when ``asset`` 
carries one
+        (falling back to the asset name).
+    :param asset: An asset decorated with 
:func:`~airflow.providers.common.dataquality.assets.asset_quality`.
+        Supplies defaults for ``ruleset``, ``table``, and ``conn_id`` 
(explicit arguments
+        win) and is automatically added to the task's outlets so its asset 
events carry
+        the check summary.
+    :param partition_clause: Predicate ANDed into every built-in check's WHERE 
clause,
+        e.g. ``"ds = '{{ ds }}'"``.
+    :param fail_on: Severity that fails the task: ``error`` (default — 
warn-severity rule
+        failures are recorded but don't fail), ``warn`` (any rule failure 
fails), or
+        ``never`` (only execution errors fail).
+    :param conn_id: Connection to the database to check (any 
``DbApiHook``-compatible type).
+    :param database: Optional database/schema overriding the connection's 
default.
+
+    Results are persisted to the backend configured under 
``[common.dataquality] results_path``; when that's
+    unset, checks still run but no history is persisted. There is no 
per-operator override --
+    all checks in a deployment share one results store.
+    """
+
+    template_fields: Sequence[str] = ("table", "partition_clause", 
*BaseSQLOperator.template_fields)
+    ui_color: str = "#87ceeb"
+
+    def __init__(
+        self,
+        *,
+        ruleset: RuleSet | dict[str, Any] | str | None = None,
+        table: str | None = None,
+        asset: Asset | None = None,
+        partition_clause: str | None = None,
+        fail_on: str = "error",
+        **kwargs,
+    ) -> None:
+        if asset is not None:
+            config = get_asset_quality_config(asset) or {}
+            ruleset = ruleset if ruleset is not None else config.get("ruleset")
+            table = table or config.get("table") or asset.name
+            kwargs.setdefault("conn_id", config.get("conn_id"))
+            outlets = list(kwargs.get("outlets") or [])
+            if asset not in outlets:
+                outlets.append(asset)
+            kwargs["outlets"] = outlets
+        super().__init__(**kwargs)

Review Comment:
   When `asset` is provided but its quality config does not include `conn_id`, 
`kwargs.setdefault("conn_id", config.get("conn_id"))` sets `conn_id=None`, 
which later causes `BaseSQLOperator.get_db_hook()` to fail with an unclear 
error. Only default `conn_id` from the asset when it is set, and fail fast with 
a clear ValueError when `conn_id` is still missing after initialization.



##########
providers/common/dataquality/src/airflow/providers/common/dataquality/example_dags/example_dq_ruleset_from_yaml.py:
##########
@@ -0,0 +1,83 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+"""
+Example DAG: load a ruleset from a YAML file instead of declaring it in Python.
+
+A path string is accepted anywhere a 
:class:`~airflow.providers.common.dataquality.rules.RuleSet` is --
+``DQCheckOperator(ruleset=...)``, ``@task.dq_check(ruleset=...)``, and
+:func:`~airflow.providers.common.dataquality.assets.asset_quality` all resolve 
it via
+:meth:`~airflow.providers.common.dataquality.rules.RuleSet.from_file` at 
Dag-parse time. This keeps rules
+editable by people who don't write Python -- a data steward can change 
``orders_ruleset.yaml``
+without touching the Dag file.
+"""
+
+from __future__ import annotations
+
+import os
+from datetime import datetime
+from pathlib import Path
+
+from airflow.providers.common.dataquality.operators.dq_check import 
DQCheckOperator
+from airflow.providers.common.sql.operators.sql import SQLExecuteQueryOperator
+from airflow.sdk import DAG
+
+DAG_ID = "example_dq_ruleset_from_yaml"
+CONN_ID = "sqlite_default"
+TABLE_NAME = "dq_yaml_orders"
+RESULTS_PATH = Path("/tmp/airflow_dq_example/results")
+RULESET_FILE = Path(__file__).parent / "orders_ruleset.yaml"
+
+os.environ.setdefault("AIRFLOW__DQ__RESULTS_PATH", f"file://{RESULTS_PATH}")

Review Comment:
   The provider reads `results_path` from the `[common.dataquality]` config 
section, so `AIRFLOW__DQ__RESULTS_PATH` will not configure the results backend. 
Use `AIRFLOW__COMMON_DATAQUALITY__RESULTS_PATH` here so the example actually 
persists results.



##########
providers/common/dataquality/src/airflow/providers/common/dataquality/example_dags/example_dq_require_quality.py:
##########
@@ -0,0 +1,120 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+"""
+Example DAGs: gate a consumer Dag on the data quality score of the asset that 
triggers it.
+
+Two Dags, wired together only through the ``dq_gated_orders`` asset:
+
+- ``example_dq_require_quality_producer`` checks a table and produces the 
asset.
+  
:class:`~airflow.providers.common.dataquality.operators.dq_check.DQCheckOperator`
 attaches its summary
+  (including the quality ``score``) to the asset event automatically because 
the asset carries
+  quality config attached with 
:func:`~airflow.providers.common.dataquality.assets.asset_quality`.
+- ``example_dq_require_quality_consumer`` is scheduled by that asset. Its 
first task, built by
+  :func:`~airflow.providers.common.dataquality.assets.require_quality`, reads 
the score off the triggering
+  asset event and short-circuits -- skipping every downstream task -- when 
it's missing or
+  below ``min_score``. Downstream tasks never see a run triggered by a bad 
batch of data.
+"""
+
+from __future__ import annotations
+
+import os
+from datetime import datetime
+from pathlib import Path
+
+from airflow.providers.common.dataquality.assets import asset_quality, 
require_quality
+from airflow.providers.common.dataquality.operators.dq_check import 
DQCheckOperator
+from airflow.providers.common.dataquality.rules import DQRule, RuleSet
+from airflow.providers.common.sql.operators.sql import SQLExecuteQueryOperator
+from airflow.sdk import DAG, Asset, task
+
+CONN_ID = "sqlite_default"
+TABLE_NAME = "dq_gated_orders"
+RESULTS_PATH = Path("/tmp/airflow_dq_example/results")
+
+os.environ.setdefault("AIRFLOW__DQ__RESULTS_PATH", f"file://{RESULTS_PATH}")

Review Comment:
   The provider reads `results_path` from the `[common.dataquality]` config 
section (env var name is derived from `section.replace('.', '_')`), so 
`AIRFLOW__DQ__RESULTS_PATH` will not configure the results backend. Use 
`AIRFLOW__COMMON_DATAQUALITY__RESULTS_PATH` here so the example actually 
persists results.



##########
airflow-core/tests/unit/always/test_project_structure.py:
##########
@@ -107,6 +107,7 @@ def test_providers_modules_should_have_tests(self):
             
"providers/common/compat/tests/unit/common/compat/standard/test_utils.py",
             
"providers/common/messaging/tests/unit/common/messaging/providers/test_base_provider.py",
             
"providers/common/messaging/tests/unit/common/messaging/providers/test_sqs.py",
+            
"providers/common/dataquality/tests/unit/common/dataquality/test_exceptions.py",

Review Comment:
   This adds 
`providers/common/dataquality/tests/unit/common/dataquality/test_exceptions.py` 
to `OVERLOOKED_TESTS`, which suppresses the missing-tests check rather than 
fixing it. Since this PR introduces the `exceptions.py` module, please add the 
missing `test_exceptions.py` file (even a minimal import/instantiation test) 
and remove this entry from `OVERLOOKED_TESTS`.



##########
providers/common/dataquality/src/airflow/providers/common/dataquality/example_dags/example_dq_check_custom_sql.py:
##########
@@ -0,0 +1,112 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+"""
+Example DAG: ``custom_sql`` for checks the built-in catalog can't express.
+
+Built-in checks (``null_count``, ``min``, ``max``, ...) are all single-column. 
The moment a
+rule needs to compare two columns, join against another table, or use a SQL 
function the
+built-in catalog doesn't cover (or that your database's ``DbApiHook`` doesn't 
support -- see
+"Supported checks and databases" in the provider docs), ``custom_sql`` is the 
escape hatch:
+any statement that resolves to a single scalar, evaluated the same way as a 
built-in check.
+"""
+
+from __future__ import annotations
+
+import os
+from datetime import datetime
+from pathlib import Path
+
+from airflow.providers.common.dataquality.operators.dq_check import 
DQCheckOperator
+from airflow.providers.common.dataquality.rules import DQRule, RuleSet, 
Severity
+from airflow.providers.common.sql.operators.sql import SQLExecuteQueryOperator
+from airflow.sdk import DAG
+
+DAG_ID = "example_dq_check_custom_sql"
+CONN_ID = "sqlite_default"
+TABLE_NAME = "dq_custom_sql_orders"
+RESULTS_PATH = Path("/tmp/airflow_dq_example/results")
+
+os.environ.setdefault("AIRFLOW__DQ__RESULTS_PATH", f"file://{RESULTS_PATH}")

Review Comment:
   The provider reads `results_path` from the `[common.dataquality]` config 
section, so `AIRFLOW__DQ__RESULTS_PATH` will not configure the results backend. 
Use `AIRFLOW__COMMON_DATAQUALITY__RESULTS_PATH` here so the example actually 
persists results.



##########
providers/common/dataquality/src/airflow/providers/common/dataquality/example_dags/example_dq_check_decorator_dynamic.py:
##########
@@ -0,0 +1,94 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+"""
+Example DAG: ``@task.dq_check`` with a runtime ruleset.
+
+``table`` (or ``asset``) is declared as a decorator argument, exactly like the 
plain operator.
+``ruleset`` may be declared at Dag-parse time, or returned by the decorated 
function at
+execution time. This is useful when an upstream task, variable, or generated 
value decides which
+ruleset to run.
+"""
+
+from __future__ import annotations
+
+import os
+from datetime import datetime
+from pathlib import Path
+
+from airflow.providers.common.dataquality.rules import DQRule, RuleSet
+from airflow.providers.common.sql.operators.sql import SQLExecuteQueryOperator
+from airflow.sdk import DAG, task
+
+DAG_ID = "example_dq_check_decorator_dynamic"
+CONN_ID = "sqlite_default"
+TABLE_NAME = "dq_dynamic_orders"
+RESULTS_PATH = Path("/tmp/airflow_dq_example/results")
+
+os.environ.setdefault("AIRFLOW__DQ__RESULTS_PATH", f"file://{RESULTS_PATH}")

Review Comment:
   The provider reads `results_path` from the `[common.dataquality]` config 
section, so `AIRFLOW__DQ__RESULTS_PATH` will not configure the results backend. 
Use `AIRFLOW__COMMON_DATAQUALITY__RESULTS_PATH` here so the example actually 
persists results.



##########
providers/common/dataquality/src/airflow/providers/common/dataquality/example_dags/example_dq_llm_generated_ruleset.py:
##########
@@ -0,0 +1,128 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+"""
+Example DAG: generate a ``RuleSet`` with an LLM, guided by the 
``dataquality-rule-authoring`` skill.
+
+Requires the optional ``apache-airflow-providers-common-ai[skills]`` package 
and a configured
+LLM connection (``llm_conn_id``); this Dag is not registered when common.ai 
isn't installed.
+
+An LLM is asked to propose data quality rules for a table's columns. Its 
``system_prompt``
+points it at the ``dataquality-rule-authoring`` skill shipped with this 
provider (via
+``AgentSkillsToolset``), so it knows the exact ``RuleSet``/``DQRule`` schema, 
the built-in check
+catalog, and the ``Condition`` grammar, instead of guessing at field or check 
names.
+``output_type=RuleSet`` makes pydantic-ai validate -- and self-correct -- the 
model's output
+against the real ``RuleSet`` model before the task completes, so a malformed 
rule never reaches
+``DQCheckOperator`` in the first place.
+
+The generated ``RuleSet`` is then returned by ``@task.dq_check`` at runtime, 
since the real
+ruleset doesn't exist until the LLM task runs.
+"""
+
+from __future__ import annotations
+
+import os
+from datetime import datetime
+from pathlib import Path
+
+from airflow.providers.common.dataquality.rules import RuleSet
+from airflow.providers.common.sql.operators.sql import SQLExecuteQueryOperator
+from airflow.sdk import DAG, task
+
+try:
+    from airflow.providers.common.ai.toolsets.skills import AgentSkillsToolset
+except ImportError:
+    AgentSkillsToolset = None  # type: ignore[assignment,misc]
+
+DAG_ID = "example_dq_llm_generated_ruleset"
+CONN_ID = "sqlite_default"
+TABLE_NAME = "dq_llm_orders"
+RESULTS_PATH = Path("/tmp/airflow_dq_example/results")
+# The skill ships next to this Dag's package, not next to this file -- resolve 
relative to
+# __file__ so the path holds regardless of the Dag processor's working 
directory.
+SKILLS_DIR = Path(__file__).parent.parent / "skills" / 
"dataquality-rule-authoring"
+
+os.environ.setdefault("AIRFLOW__DQ__RESULTS_PATH", f"file://{RESULTS_PATH}")

Review Comment:
   The provider reads `results_path` from the `[common.dataquality]` config 
section, so `AIRFLOW__DQ__RESULTS_PATH` will not configure the results backend. 
Use `AIRFLOW__COMMON_DATAQUALITY__RESULTS_PATH` here so the example actually 
persists results.



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