aminghadersohi commented on code in PR #43870:
URL: https://github.com/apache/superset/pull/43870#discussion_r4263831906
##########
superset/mcp_service/dataset/schemas.py:
##########
@@ -207,6 +207,16 @@ class DatasetInfo(BaseModel):
url: str | None = Field(None, description="Explore view URL for this
dataset")
sql: str | None = Field(None, description="SQL for virtual datasets")
main_dttm_col: str | None = Field(None, description="Main datetime column")
+ partition_column: str | None = Field(
Review Comment:
These two fields grow the dataset tools' output schemas by 337 B, so
`test_native_inventory_report_matches_registered_tools` fails `unit-tests
(current)`. Rerun it with `SUPERSET_MCP_UPDATE_TOOL_INVENTORY=1` and commit
`native_tool_inventory.json` (no suggestion: that file is outside the diff).
##########
superset/views/datasource/views.py:
##########
@@ -293,6 +425,72 @@ def save(self) -> FlaskResponse:
),
status=409,
)
+ # The mapping's one-transform invariant, against the columns this
+ # request is about to write. `update_from_object` sets every field in
+ # `update_from_object_fields` straight onto the column, so nothing
+ # between here and storage would notice a transform parked on a column
+ # the mapping does not mirror -- invisible in the editor, since no row
+ # but the mapped one renders a transform, and live the moment the
mapped
+ # column resolves back to it. `DatasetDAO.update` runs a model-level
+ # pass for this; this endpoint bypasses that along with the rest of
+ # `UpdateDatasetCommand`.
+ #
+ # Corrected rather than refused, unlike the gates below. Those are
about
+ # a value that may not be stored anywhere; this is about a value in the
+ # wrong place, and the payload a GET-then-POST client sends back
carries
+ # whatever a previous writer left there -- so a 422 would punish the
+ # client that is merely echoing the state it was given.
+ #
+ # Which is also why it runs *first*. A parked transform that is not a
+ # storable expression would otherwise fail the gate below and 422 every
+ # save, leaving the dataset uneditable over a value nobody asked to
+ # keep; dropped here, there is nothing left for that gate to refuse.
+ # What it still guards is the transform this request actually stores,
+ # the one on the mapped column.
+ #
+ # Read from the payload alone, with no fallback to the model: every
+ # field here rides in on `update_from_object`, which writes
+ # `obj.get(attr)` for each one, so what this request says *is* what the
+ # mapping will be.
+ if cleared := drop_unmapped_value_transforms(
+ datasource_dict.get("columns"),
+ partition_column=datasource_dict.get("partition_column"),
+
partition_mapped_column=datasource_dict.get("partition_mapped_column"),
+ main_dttm_col=datasource_dict.get("main_dttm_col"),
+ # So an unchanged echo of stored configuration survives: this
+ # endpoint's own client does GET-then-POST, which is exactly the
+ # shape that looked like a value being parked.
+ stored_by_name={
+ column.column_name: (
+ column.partition_value_transform,
+ bool(column.partition_transform_is_monotonic),
+ )
+ for column in getattr(orm_datasource, "columns", None) or []
+ },
Review Comment:
With the flag on, this endpoint has no model-level pass, so the echo
exemption keeps the transform on the old mapped column; REST PUT's post-pass
clears it. Clearing the override later through this endpoint then re-arms it.
```suggestion
stored_by_name=None
if is_feature_enabled("PARTITION_FILTER_MAPPING")
else {
column.column_name: (
column.partition_value_transform,
bool(column.partition_transform_is_monotonic),
)
for column in getattr(orm_datasource, "columns", None) or []
},
```
##########
superset/connectors/sqla/partition_mapping.py:
##########
@@ -0,0 +1,3128 @@
+# 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.
+"""
+Partition filter mapping.
+
+Datasets on Hadoop-family engines are commonly partitioned on a *technical*
+column -- an epoch integer, a lowercased region key -- that no analyst would
+filter on. Unless a query carries a predicate on that column the engine scans
+every partition.
+
+A dataset owner names one partition column ``p``, one business column that
+filters are mirrored from, and a value transform ``T`` (a SQL expression
+containing a ``:value`` placeholder). Superset then appends an equivalent
+predicate on ``p`` to every query, so chart authors change nothing and queries
+prune.
+
+The load-bearing assumption
+---------------------------
+Everything here reasons about ``T(col) op T(v)``, but what is emitted is
+``p op T(v)`` -- a predicate on a *physically different column*. The step from
+one to the other is::
+
+ p = T(mapped_col) for every row in the table
+
+Superset cannot verify that; it is a property of whatever ETL populates the
+partition column. If that job lags, backfills with different logic, or writes
+the partition key in a different timezone, mirrored predicates silently drop
+real rows. The mapping is only as trustworthy as the pipeline behind it.
+
+Operator safety
+---------------
+A mirrored predicate ``P2`` may only be ``AND``-ed onto a query when the
+original predicate ``P1`` *implies* it:
+
+=========================================== =============================
+Original Safe when
+=========================================== =============================
+``col = v``, ``col IN (...)`` ``T`` is a function *and* the
+ engine compares ``col``
+ byte-exactly
+``col >=|>|<|<= v``, ``TEMPORAL_RANGE`` only if ``T`` is monotonic
+``col != v``, ``NOT IN``, ``LIKE``, ... never
+=========================================== =============================
+
+Monotonic here means non-decreasing, not strictly increasing: a bucketing
+transform such as a day key is monotonic and maps a whole day of timestamps
+onto one value. ``col < v`` then only implies ``T(col) <= T(v)``, so a strict
+bound is mirrored non-strictly -- see `mirror_operator`.
+
+Equality under the engine's own rules
+-------------------------------------
+"``T`` is a function" gives ``col = v`` implies ``T(col) = T(v)`` for *value*
+equality. The engine compares with *SQL* equality, and the two part company
+wherever that comparison is not byte-exact: under a case-insensitive collation
+a stored ``country`` of ``'us'`` satisfies a filter for ``'US'``, while the
+mirror ``region_key = hex('US')`` excludes the row and the chart loses it with
+nothing to indicate why. Trailing-space-insensitive ``CHAR`` comparison says
+the same thing about padding.
+
+So equality and ``IN`` are withdrawn for a *string* mapped column unless the
+engine spec declares ``binary_string_comparison`` -- `equality_mirrors_safely`.
+Numeric and temporal comparison is exact everywhere and is untouched, and range
+mirroring is untouched too: it already rests on the owner declaring ``T``
+order-preserving *with respect to the column's own order*, which is an
+assertion about the very semantics this is checking for.
+
+What the gate cannot see is a column declaring its own collation
+(``country COLLATE NOCASE``) on an otherwise byte-exact engine. Nothing in
+SQLAlchemy's reflection or the engine specs exposes that, so there it remains
+the owner's assumption, like ``p = T(mapped_col)`` itself.
+
+Resolution of the value the engine compares
+-------------------------------------------
+Every row of the table above assumes the engine compares the value the mirror
+was built from. It does not always. A ``DATE`` column compared against
+``'2026-07-06 10:08:11'`` is compared on the date part alone -- whether the
+engine writes the literal itself (``TO_DATE('2026-07-06', 'YYYY-MM-DD')`` on
+Postgres, ``DATE '2026-07-06'`` on Presto, Trino, BigQuery and some two dozen
+others) or applies an implicit cast to a bound string. The filter therefore
+keeps the whole of that day while ``p = T(2026-07-06 10:08:11)`` keeps one
+instant of it: narrower than the predicate it stands in for, which is the one
+thing a mirror may never be.
+
+What an engine throws away is detected from the column's type rather than
+enumerated per engine -- `ExploreMixin._engine_literal_resolution` -- and what
+to do about it is a property of the *operator*, not of the value:
+
+* a bound rounds outward, backward for a lower one and forward for an upper
one,
+ through `ExploreMixin._round_bounds_outward`. The mirror then reads one extra
+ bucket at the edge, and the original predicate is still in the query to
+ exclude the rows that bucket adds.
+* an equality, or one member of an ``IN`` list, has nowhere to widen to: these
+ predicates are ``AND``-ed onto the query, so "or the day either side" is not
+ something the mirror can express. They decline, which costs the query its
+ pruning and nothing else.
+
+So a ``DATE``-typed mapped column mirrors a range at day granularity, and does
+not mirror an equality whose value carries a time of day at all. Map a
+``TIMESTAMP`` column instead and every operator is available again.
+
+Negations are never safe because ``T`` need not be injective:
+``lower(:value)`` with ``country != 'US'`` mirrors to ``region_key != 'us'``,
+which wrongly excludes rows whose ``country`` is already lowercase ``'us'`` --
+rows the original filter *keeps*.
+
+Monotonicity is a property of the transform, not of the column's data type:
+``hour(:value)``, ``date_format(:value, 'dd')`` and ``dayofweek(:value)`` are
+all reasonable transforms on a ``TIMESTAMP`` column and none of them preserve
+ordering. It is therefore declared by the owner, not inferred.
+
+Time grains
+-----------
+A grained filter -- drill-to-detail, mostly -- compares the *truncated* column,
+``trunc(col) op v``, so the raw bounds it carries do not describe the rows it
+keeps. A row in the final partial bucket satisfies ``trunc(col) < until`` while
+``col < until`` excludes it.
+
+Which direction a grain rounds is not knowable from the duration alone, and the
+obvious guess is wrong: ``WEEK_ENDING_SATURDAY`` rounds *forward* on Hive and
+Presto, and Ocient's grains are ``ROUND``, i.e. to nearest. What every grain
+does satisfy is a bound on the displacement::
+
+ |trunc(ts) - ts| < width(grain)
+
+so widening *both* bounds by one bucket width is no narrower than the real
+predicate whichever way the grain rounds -- and it needs no monotonicity of
+``trunc`` itself, which is what rescues Hive's oddly-anchored ``P1W``. Width is
+a property of the grain, not of the engine, which is what makes this
+maintainable; see `grain_bucket_width`. A grain whose SQL an operator supplied
+has no known width, and does not mirror at all.
+"""
+
+from __future__ import annotations
+
+import hashlib
+import logging
+import numbers
+import re
+from collections.abc import Sequence
+from dataclasses import dataclass
+from datetime import date, datetime
+from functools import lru_cache
+from typing import Any, cast, TYPE_CHECKING
+
+import numpy as np
+import pandas as pd
+import sqlalchemy as sa
+from dateutil.relativedelta import relativedelta
+from flask import current_app as app
+from flask_babel import lazy_gettext as _
+from sqlalchemy.engine.interfaces import Dialect
+from sqlalchemy.sql.elements import ColumnElement
+
+from superset.constants import LRU_CACHE_MAX_SIZE, TimeGrain
+from superset.exceptions import (
+ QueryClauseValidationException,
+ SupersetParseError,
+ SupersetSecurityException,
+)
+from superset.extensions import cache_manager, feature_flag_manager
+from superset.sql.parse import SQLScript, SQLStatement
+from superset.superset_typing import FilterValues
+from superset.utils import core as utils, json
+from superset.utils.core import FilterOperator, get_username
+
+if TYPE_CHECKING:
+ from superset.connectors.sqla.models import SqlaTable, TableColumn
+ from superset.db_engine_specs.base import BaseEngineSpec
+ from superset.models.core import Database
+
+logger = logging.getLogger(__name__)
+
+FEATURE_FLAG = "PARTITION_FILTER_MAPPING"
+
+#: Longest transform accepted anywhere. A transform is one SQL expression an
+#: owner types by hand, so this is generous; the point is that it is bounded.
+#: The bound matters because `is_transform_active` parses the stored value on
+#: each Explore load, and an unbounded string would make that parse the
+#: expensive part of rendering a chart.
+#:
+#: The typed column field, the import schema and the preview request each
+#: enforce it through a marshmallow `Length` validator, which is what produces
+#: the per-field message those three callers want. `stored_expression_error`
+#: enforces it too, for the paths that load no schema -- the deprecated
+#: `POST /datasource/save/` is one, and it writes straight through
+#: `update_from_object`.
+MAX_TRANSFORM_LENGTH = 1024
+
+#: Placeholder the owner writes in the transform, e.g.
``unix_timestamp(:value)``.
+#: Matched with word boundaries so ``:values`` is not mistaken for it.
+VALUE_PLACEHOLDER_RE = re.compile(r":value\b")
+
+#: The opening and closing delimiters of each kind of Jinja block. The probe
+#: would render these in a different context at a different time from the chart
+#: query, so a transform holding one is rejected at save time.
+JINJA_BLOCK_DELIMITERS = (("{{", "}}"), ("{%", "%}"), ("{#", "#}"))
+
+#: MySQL and MariaDB "executable comments": ``/*!50000 ... */`` and
+#: ``/*M!50000 ... */`` are comments to every other reader and *statement text*
+#: to those two engines.
+#:
+#: This is the one construct that breaks the premise the probe's shape gates
+#: rest on -- that the parse this module inspects and the statement the engine
+#: runs are the same statement. ``1 /*!50000 + (SELECT secret FROM vault) */``
+#: parses with no sub-query and no FROM, clears `stored_expression_error` and
+#: `probe_sql_is_evaluable` alike, and then reads a table on MySQL. The result
+#: comes back to a dataset owner through the preview's ``emitted_predicate``,
+#: with no RLS applied and no SQL Lab access needed.
+#:
+#: Refused on every engine rather than only the two that honour it. A transform
+#: is a scalar function of ``:value``; there is no legitimate reason for one to
+#: carry a comment of any kind, let alone this one, and a per-engine gate would
+#: store a transform on Postgres that detonates when the dataset is re-pointed
+#: at MySQL.
+EXECUTABLE_COMMENT_RE = re.compile(r"/\*M?!")
+
+#: A PostgreSQL Unicode-escaped identifier, ``U&"..."``.
+#:
+#: The second construct that breaks the premise above, and in the same way:
+#: ``U&"\\0071uery_to_xml"(...)`` parses as an anonymous function whose name is
+#: the *literal* ``\\0071uery_to_xml``, so the function denylist is matching a
+#: name the engine never sees -- PostgreSQL decodes the escape and runs
+#: ``query_to_xml``, handing a dataset owner rows from outside their RLS scope
+#: through the preview's ``emitted_predicate``.
+#:
+#: Normalizing the escapes and re-checking would be the other repair, and is
+#: worse: it means reimplementing one engine's identifier decoding well enough
+#: to be a security boundary. Refusing the construct is exact, and costs
+#: nothing real -- a transform is a scalar function of ``:value``, and there is
+#: no reason to name a function or column through an escape sequence.
+#:
+#: Refused on every engine, like the executable comment, so a transform stored
+#: on SQLite cannot detonate when the dataset is re-pointed at PostgreSQL. The
+#: ``&`` may be separated from the ``U`` by nothing at all, but whitespace or a
+#: comment between the prefix and the string is not accepted by PostgreSQL
+#: either, so the strict form is the whole surface.
+#:
+#: Matched in raw text, so the prefix is refused inside a string literal too.
+#: That is the same trade the executable comment makes and has the same
+#: justification: a gate whose contract is to fire *before* the parse cannot
+#: ask the parse whether the text was quoted. ``concat(:value, 'u&"x"')`` is
+#: refused, which costs an owner nothing anyone writes.
+UNICODE_ESCAPED_IDENTIFIER_RE = re.compile(r'\bU&"', re.IGNORECASE)
+
+#: Substituted for ``:value`` before parsing -- sqlglot rejects a bare
``:value``
+#: on most dialects. Mirrors the ``_JINJA_BLOCK_RE`` -> ``NULL`` trick used by
+#: ``validate_stored_expression``.
+_PARSE_STANDIN = "NULL"
+
+#: Substituted for ``:value`` to find out *where* the placeholder landed, which
+#: `_PARSE_STANDIN` cannot answer: ``NULL`` is a keyword, so after substitution
+#: the parse tree no longer records that a placeholder was ever there. An
+#: identifier does leave a trace -- a column reference -- and one that is
+#: missing is a placeholder the engine will never evaluate.
+#:
+#: Named so it cannot plausibly collide with a real column, but a transform
that
+#: writes it anyway is refused rather than counted. A hand-written occurrence
+#: does not merely make the count disagree: it *supplies* the column reference
a
+#: non-executable placeholder failed to produce, and the two cancel exactly.
See
+#: `placeholder_is_executable`.
+_PLACEHOLDER_STANDIN = "superset_pfm_value_standin"
+
+#: Functions whose value depends on wall-clock time or randomness. The probe
+#: runs in a different session at a different moment from the chart query and
+#: its result is then cached, so any of these freezes a snapshot of probe time
+#: into the emitted predicate: a transform such as
+#: ``datediff(day, :value, LOCALTIMESTAMP)`` for a relative partition key is
+#: evaluated once and then keeps emitting yesterday's answer, so the chart
+#: silently drops rows after midnight.
+#:
+#: Matched by SQL function name, so every engine's spelling of "now" has to be
+#: named -- the ANSI four were not enough. Listed rather than delegated to the
+#: engine specs because the risk is the same everywhere and a spec that had not
+#: got round to declaring its own would fail open; a name no engine has is
+#: inert, so over-listing costs nothing.
+NON_DETERMINISTIC_FUNCTIONS = {
+ # ANSI, and the engines that spell it this way.
+ "CURRENT_DATE",
+ "CURRENT_TIME",
+ "CURRENT_TIMESTAMP",
+ "LOCALTIME",
+ "LOCALTIMESTAMP",
+ "NOW",
+ "RAND",
+ "RANDOM",
+ "UUID",
+ # PostgreSQL. `now()` is statement-stable; these two are not even that.
+ "CLOCK_TIMESTAMP",
+ "STATEMENT_TIMESTAMP",
+ "TIMEOFDAY",
+ # MySQL and MariaDB.
+ "CURDATE",
+ "CURTIME",
+ "SYSDATE",
+ "UTC_DATE",
+ "UTC_TIME",
+ "UTC_TIMESTAMP",
+ "UUID_SHORT",
+ # Oracle.
+ "SYSTIMESTAMP",
+ "SYS_GUID",
+ # SQL Server.
+ "GETDATE",
+ "GETUTCDATE",
+ "SYSDATETIME",
+ "SYSUTCDATETIME",
+ "SYSDATETIMEOFFSET",
+ "NEWID",
+ # BigQuery.
+ "CURRENT_DATETIME",
+ "GENERATE_UUID",
+ # Snowflake.
+ "RANDSTR",
+ "UUID_STRING",
+ # ClickHouse.
+ "NOW64",
+ "RANDCANONICAL",
+ "GENERATEUUIDV4",
+ # H2 and Derby, which the test fixtures use.
+ "RANDOM_UUID",
+}
+
+#: Functions that mean "now" only in their zero-argument form. On Hive and
+#: Impala ``unix_timestamp()`` is the current time while ``unix_timestamp(x)``
+#: -- the canonical transform for this feature -- is pure.
+NON_DETERMINISTIC_WHEN_NILADIC = {"UNIX_TIMESTAMP"}
+
+#: Safe for any function ``T``.
+MIRRORABLE_ALWAYS = {FilterOperator.EQUALS, FilterOperator.IN}
+
+#: Safe only when ``T`` preserves ordering.
+MIRRORABLE_IF_MONOTONIC = {
+ FilterOperator.GREATER_THAN,
+ FilterOperator.GREATER_THAN_OR_EQUALS,
+ FilterOperator.LESS_THAN,
+ FilterOperator.LESS_THAN_OR_EQUALS,
+ FilterOperator.TEMPORAL_RANGE,
+}
+
+
+#: Every operator that can be mirrored under *some* transform. The preview
+#: endpoint accepts these; whether a given one actually mirrors still depends
on
+#: the monotonicity declaration.
+MIRRORABLE_OPERATORS = MIRRORABLE_ALWAYS | MIRRORABLE_IF_MONOTONIC
+
+#: Operators the preview endpoint can construct. `TEMPORAL_RANGE` is mirrored
by
+#: the query path, but as *two* bounds that `_collect_partition_mirror_range`
+#: decomposes a time range into -- the preview request carries sample values,
not
+#: a since/until pair, so there is no range for it to build. The editor never
+#: asks for one either: `previewOperatorFor` sends `>=`, `=` or `IN`.
+PREVIEWABLE_OPERATORS = MIRRORABLE_OPERATORS - {FilterOperator.TEMPORAL_RANGE}
+
+
+class Unmirrorable:
+ """
+ A filter no mirror can stand in for, and why.
+
+ Returned by `ExploreMixin.mirror_probe_request` for a value the engine
+ compares more coarsely than the filter carries, one it cannot render as a
+ literal, one in a time frame the transform would discard, or an ``IN`` list
+ with a member of any of those kinds. An object rather than `None`, because
+ `None` is a filter value in its own right.
+
+ The reason rides along because the preview has to explain the decline to
+ the owner, and the two declines want different advice: "the engine compares
+ less of this value than you typed, so map a column it compares in full" is
+ sound guidance for a `DATE` column and actively misleading for an
+ offset-bearing bound on a `TIMESTAMP` one, which already is such a column.
+ Carried rather than re-derived so the preview's explanation cannot come
+ apart from the chart path's decision.
+
+ Lives here rather than beside that method so the preview can read it too:
+ `superset.models.helpers` imports this module, so these can only cross the
+ boundary in this direction. Both callers recognise the same instances -- a
+ preview that answered "valid" for a request the chart path declines is the
+ drift this is here to prevent.
+ """
+
+ __slots__ = ("reason",)
+
+ def __init__(self, reason: str) -> None:
+ self.reason = reason
+
+ def __repr__(self) -> str:
+ return f"<Unmirrorable {self.reason}>"
+
+
+#: The ordinary decline: whatever the mirror cannot be built from, with the
+#: engine's own comparison resolution as the reason an owner can act on.
+UNMIRRORABLE = Unmirrorable("resolution")
+
+#: A value carrying a UTC offset, declined whatever the column's resolution.
+#: A transform such as ``CAST(:value AS TIMESTAMP)`` drops the offset, so even
+#: an engine that compares the whole instant would be probed in the wrong
+#: frame -- which is not something mapping a different column fixes.
+UNMIRRORABLE_OFFSET = Unmirrorable("offset")
+
+
+def is_unmirrorable(value: Any) -> bool:
+ """Whether `mirror_probe_request` declined this request."""
+ return isinstance(value, Unmirrorable)
+
+
+#: A transform that preserves ordering need not be *strictly* increasing: a day
+#: key such as ``to_char(ts, 'YYYYMMDD')`` maps a whole day of timestamps onto
+#: one value. For such a ``T``, ``col < v`` only implies ``T(col) <= T(v)`` and
+#: ``col > v`` only implies ``T(col) >= T(v)`` -- the rows in the bucket at the
+#: boundary satisfy the non-strict form and not the strict one. A strict mirror
+#: therefore drops rows the filter keeps, which is the one thing a mirror may
+#: never do, so a strict bound is mirrored non-strictly.
+_NON_STRICT_EQUIVALENT = {
+ FilterOperator.GREATER_THAN: FilterOperator.GREATER_THAN_OR_EQUALS,
+ FilterOperator.LESS_THAN: FilterOperator.LESS_THAN_OR_EQUALS,
+}
+
+
+def mirror_operator(operator: FilterOperator) -> FilterOperator:
+ """
+ The operator a mirrored predicate uses to stand in for ``operator``.
+
+ Strict bounds widen; everything else passes through. Idempotent, so it is
+ safe wherever a request may already have been widened.
+
+ The widened bound reads one extra partition at the edge, and the original
+ predicate is still in the query to exclude the rows that partition adds --
+ the same trade as the grain widening and the ``NULL``-partition escape.
+ Declaring the transform strictly increasing would buy that partition back,
+ which is not worth a second property only the owner can vouch for.
+ """
+ return _NON_STRICT_EQUIVALENT.get(operator, operator)
+
+
+def mirrorable_operators(
+ is_monotonic: bool, *, equality_is_safe: bool = True
+) -> set[FilterOperator]:
+ """
+ The operators whose predicates may be mirrored onto the partition column.
+
+ :param is_monotonic: whether the owner declared the transform
+ order-preserving
+ :param equality_is_safe: whether the engine's ``=`` on the mapped column
+ compares the way ``T`` was written against -- see
+ `equality_mirrors_safely`
+
+ Both call sites -- the query path through `PartitionMapping.mirrors` and
the
+ Explore indicator through `partition_filter_mapping_summary` -- come
through
+ here, which is what keeps the glyph from promising pruning the SQL will not
+ do.
+ """
+ operators = MIRRORABLE_ALWAYS if equality_is_safe else set()
+ if is_monotonic:
+ operators = operators | MIRRORABLE_IF_MONOTONIC
+ return set(operators)
+
+
+#: Declared types whose comparison ignores trailing blanks.
+#:
+#: The fixed-width character types, which the SQL standard has compare as
+#: though both sides were padded to the same length -- so ``'US'`` and
+#: ``'US '`` are equal in a ``CHARACTER(3)``, while ``lower()`` of the two is
+#: not. Spelled out rather than matched by prefix because the variable-width
+#: names start with the same letters: ``VARCHAR`` and ``CHARACTER VARYING``
+#: compare the blanks and must not land here.
+PADDED_CHARACTER_TYPES = frozenset(
+ {
+ "CHAR",
+ "NCHAR",
+ # PostgreSQL's own name for ``CHARACTER``, which is what reflection
+ # reports for a ``CHAR(n)`` column there.
+ "BPCHAR",
+ "CHARACTER",
+ "NATIONAL CHAR",
+ "NATIONAL CHARACTER",
+ }
+)
+
+
+def _is_padded_character_type(column: TableColumn) -> bool:
+ """
+ Whether ``column``'s declared type compares without its trailing blanks.
+
+ Read off the declared type rather than the engine spec's resolved one: the
+ specs map ``CHAR`` and ``VARCHAR`` onto the same `sqlalchemy.String`, so
+ the distinction this needs is gone by then. The length suffix is dropped
+ and the name matched against `PADDED_CHARACTER_TYPES`, so an unfamiliar
+ spelling answers ``False`` and the engine-level flag decides as before --
+ this gate adds a decline rather than lifting one. A column with no
+ declared type has nothing to read, and answers the same way.
+ """
+ if not isinstance(column.type, str):
+ return False
+ native = re.sub(r"\s+", " ", column.type.strip().upper())
+ return native.split("(")[0].strip() in PADDED_CHARACTER_TYPES
+
+
+def equality_mirrors_safely(
+ column: TableColumn | None,
+ db_engine_spec: type[BaseEngineSpec],
+) -> bool:
+ """
+ Whether ``col = v`` on this column implies ``T(col) = T(v)`` in the engine.
+
+ The operator matrix calls equality safe "for any function ``T``" because
+ ``T`` is a function, so ``col = v`` gives ``T(col) = T(v)``. That reasons
+ about *value* equality while the engine reasons about *SQL* equality, and
+ the two part company under any comparison that is not byte-exact: with a
+ case-insensitive collation a stored ``country`` of ``'us'`` satisfies a
+ filter for ``'US'``, but the mirror ``region_key = hex('US')`` excludes the
+ row and the chart loses it with no indication why.
Trailing-space-insensitive
+ ``CHAR`` comparison says the same thing about padding.
+
+ Only string columns are at risk; numeric and temporal comparison is exact
+ everywhere. And only equality: range mirroring already requires the owner
+ to declare ``T`` order-preserving *with respect to the column's own order*,
+ which is an assertion about the same comparison semantics this is checking
+ for -- so the declaration covers it where equality has nothing to cover it.
+
+ Padding is asked about per column, because it is a property of the *type*
+ rather than of the engine. ``binary_string_comparison`` speaks for an
+ engine's default text comparison, and on PostgreSQL -- which declares it
+ -- a ``CHAR(2)`` still matches a filter for ``'US '`` against a stored
+ ``'US'``, because the standard says a padded character type compares
+ without its trailing blanks. The mirror ``region_key = lower('US ')`` then
+ excludes the row. So a fixed-width character type declines whatever the
+ engine says, and an engine that ignores trailing blanks on its *variable*
+ types says so by not declaring the flag at all (see `RedshiftEngineSpec`).
+
+ What this cannot see is a column that declares its own collation
+ (``country COLLATE NOCASE``) on an otherwise byte-exact engine. Neither
+ SQLAlchemy's reflection nor the engine specs expose it, so on such a column
+ the assumption stays where ``p = T(mapped_col)`` already is: with the
owner.
+ """
+ if column is None:
+ return True
+ # Ahead of the generic-type question, which a padded type can lose: the
+ # specs map ``CHARACTER`` onto no generic type at all on some engines, and
+ # a fixed-width character type is a string whether or not Superset can say
+ # so from the name.
+ if _is_padded_character_type(column):
+ return False
+ try:
+ is_string = column.type_generic == utils.GenericDataType.STRING
+ except Exception: # pylint: disable=broad-except # noqa: BLE001
+ # An unresolvable type is treated as a string: the gate exists to stop
+ # a silent wrong answer, so it fails closed.
+ return False
+ if not is_string:
+ return True
+ return bool(db_engine_spec.binary_string_comparison)
+
+
+#: How wide one bucket of each built-in time grain is.
+#:
+#: Keyed on the ISO duration a filter carries in its ``grain``. Written out
+#: rather than parsed: four of the week grains are ISO *intervals* with an
+#: anchor (``P1W/1970-01-03T00:00:00Z``) that ``isodate.parse_duration``
+#: rejects outright, and ``PT0.5H`` / ``P0.25Y`` are fractional. A literal
+#: table is also the thing a reviewer can check a line at a time.
+#:
+#: ``relativedelta`` rather than ``timedelta`` so the calendar grains stay
+#: calendar arithmetic: a month is not 30 days.
+GRAIN_BUCKET_WIDTHS: dict[str, relativedelta] = {
+ TimeGrain.SECOND: relativedelta(seconds=1),
+ TimeGrain.FIVE_SECONDS: relativedelta(seconds=5),
+ TimeGrain.THIRTY_SECONDS: relativedelta(seconds=30),
+ TimeGrain.MINUTE: relativedelta(minutes=1),
+ TimeGrain.FIVE_MINUTES: relativedelta(minutes=5),
+ TimeGrain.TEN_MINUTES: relativedelta(minutes=10),
+ TimeGrain.FIFTEEN_MINUTES: relativedelta(minutes=15),
+ TimeGrain.THIRTY_MINUTES: relativedelta(minutes=30),
+ TimeGrain.HALF_HOUR: relativedelta(minutes=30),
+ TimeGrain.HOUR: relativedelta(hours=1),
+ TimeGrain.SIX_HOURS: relativedelta(hours=6),
+ TimeGrain.DAY: relativedelta(days=1),
+ TimeGrain.WEEK: relativedelta(days=7),
+ TimeGrain.WEEK_STARTING_SUNDAY: relativedelta(days=7),
+ TimeGrain.WEEK_STARTING_MONDAY: relativedelta(days=7),
+ TimeGrain.WEEK_ENDING_SATURDAY: relativedelta(days=7),
+ TimeGrain.WEEK_ENDING_SUNDAY: relativedelta(days=7),
+ TimeGrain.MONTH: relativedelta(months=1),
+ TimeGrain.QUARTER: relativedelta(months=3),
+ TimeGrain.QUARTER_YEAR: relativedelta(months=3),
+ TimeGrain.YEAR: relativedelta(years=1),
+}
+
+
+def grain_bucket_width(grain: str | None, engine: str) -> relativedelta | None:
+ """
+ How far a grain's truncation can move a timestamp, or ``None`` if unknown.
+
+ A grained filter compares the *truncated* column, so the raw bounds it
+ carries do not describe the rows it keeps. Widening both bounds by one
+ bucket recovers a predicate that is no narrower than the real one -- see
+ `_collect_partition_mirror_range` for the argument. That only works for a
+ grain whose bucket width Superset knows, which excludes anything an
+ operator supplied.
+
+ :param grain: the ISO duration from the filter's ``grain``
+ :param engine: the engine spec's ``engine``, to check per-engine overrides
+ """
+ if not grain:
+ return None
+
+ # An operator-declared grain carries whatever duration string they typed,
+ # and `TIME_GRAIN_ADDON_EXPRESSIONS` can redefine a *built-in* grain's SQL
+ # per engine -- `P1D` could be anything at all. Neither has a width we can
+ # claim to know, so both fall back to not mirroring.
+ if grain in app.config["TIME_GRAIN_ADDONS"]:
+ return None
+ if grain in app.config["TIME_GRAIN_ADDON_EXPRESSIONS"].get(engine, {}):
+ return None
+
+ return GRAIN_BUCKET_WIDTHS.get(grain)
+
+
+@dataclass(frozen=True)
+class PartitionMapping:
+ """A resolved, usable partition filter mapping."""
+
+ partition_column: str
+ mapped_column: str
+ value_transform: str
+ is_monotonic: bool
+ #: Whether the engine compares the mapped column the way ``T`` was written
+ #: against. Resolved once where the column and the engine are both in hand,
+ #: rather than re-derived at each `mirrors` call.
+ equality_is_safe: bool = True
+
+ def mirrors(self, operator: FilterOperator) -> bool:
+ return operator in mirrorable_operators(
+ self.is_monotonic, equality_is_safe=self.equality_is_safe
+ )
+
+
+def contains_value_placeholder(transform: str | None) -> bool:
+ """Whether the transform contains the ``:value`` placeholder."""
+ return bool(transform) and VALUE_PLACEHOLDER_RE.search(transform or "") is
not None
+
+
+def contains_executable_comment(transform: str | None) -> bool:
+ """Whether the transform carries a MySQL/MariaDB executable comment.
+
+ See `EXECUTABLE_COMMENT_RE`. Answered on raw text, like
+ `contains_jinja` and for the same reason: the whole point is that no
+ parser this module can reach reports the construct at all.
+ """
+ return bool(transform) and EXECUTABLE_COMMENT_RE.search(transform or "")
is not None
+
+
+def contains_unicode_escaped_identifier(transform: str | None) -> bool:
+ """Whether the transform names something through a ``U&"..."`` escape.
+
+ See `UNICODE_ESCAPED_IDENTIFIER_RE`. Answered on raw text for the same
+ reason as the comment above: the parse reports a name the engine does not
+ use, which is exactly what makes the denylist blind to it.
+ """
+ return (
+ bool(transform)
+ and UNICODE_ESCAPED_IDENTIFIER_RE.search(transform or "") is not None
+ )
+
+
+#: Sequence pseudo-columns, which advance a sequence when they are *read*.
+#:
+#: ``orders_seq.NEXTVAL`` parses as a qualified column reference, not a
+#: function call, so neither `SQLStatement.is_mutating` -- which walks function
+#: names -- nor the function denylist can see it. The probe would then run
+#: ``SELECT orders_seq.NEXTVAL + 1 FROM DUAL`` and advance the sequence, again
+#: on every cache expiry, for a dataset editor holding neither SQL Lab nor a
+#: DML grant. Reading one is a write however the parser classifies it.
+#:
+#: The function spelling (``nextval('s')`` on PostgreSQL) is a different shape
+#: and is caught as a function; this is only about the suffix form.
+SEQUENCE_PSEUDO_COLUMNS = frozenset({"nextval", "currval"})
+
+#: The same thing written as a call.
+#:
+#: Only the suffix form parses as a column; `nextval('s')` on PostgreSQL and
+#: DuckDB, `NEXTVAL(s)`/`SETVAL(s, 1)` on MySQL and MariaDB, and SQL Server's
+#: `NEXT VALUE FOR s` all parse as functions. `SQLStatement.is_mutating` walks
+#: function names on PostgreSQL alone -- deliberately, since the same names are
+#: read-only elsewhere -- so every other engine let these through.
+#:
+#: Matched on the name whatever the engine, because advancing a sequence is a
+#: write wherever it happens and a transform has no reason to call one.
+SEQUENCE_FUNCTIONS = frozenset(
+ {"nextval", "setval", "next_value_for", "nextvalfor", "prevval", "lastval"}
+)
+
+
+def references_sequence(statement: SQLStatement) -> bool:
+ """Whether the statement reads or advances a sequence.
+
+ Both spellings: the pseudo-column suffix, which parses as a column (see
+ `SEQUENCE_PSEUDO_COLUMNS`), and the call, which parses as a function (see
+ `SEQUENCE_FUNCTIONS`).
+
+ Answered on the parse rather than on raw text, because position is what
+ makes it the construct: a column or alias merely *called* ``nextval`` is
+ an ordinary column, and a string literal holding the word is text.
+ """
+ return bool(
+ statement.get_column_names() & SEQUENCE_PSEUDO_COLUMNS
+ or statement.get_disallowed_functions(set(SEQUENCE_FUNCTIONS))
+ )
+
+
+def contains_jinja(transform: str | None) -> bool:
+ """
+ Whether the transform contains a balanced Jinja block.
+
+ A block is an opening delimiter followed, anywhere later, by its closing
+ one -- the same thing ``{{.*?}}`` and its two siblings match under
+ ``re.DOTALL``. Scanned with `str.find` rather than that pattern, because a
+ lazy match retried from every opening delimiter is quadratic in a run of
+ them, and this runs on stored transforms with no length bound of its own:
+ `is_transform_active` reads whatever the column holds. The earliest opening
+ delimiter is the only one worth trying, since any closing delimiter after a
+ later one is also after it.
+ """
+ if not transform:
+ return False
+ for opening, closing in JINJA_BLOCK_DELIMITERS:
+ start = transform.find(opening)
+ if start != -1 and transform.find(closing, start + len(opening)) != -1:
+ return True
+ return False
+
+
+def parse_skeleton(transform: str, standin: str = _PARSE_STANDIN) -> str:
+ """
+ The transform with ``:value`` substituted out, ready for a SQL parser.
+
+ ``sanitize_clause`` / sqlglot choke on a bare ``:value`` on most dialects,
+ so the placeholder is swapped for a benign literal first -- the same trick
+ ``validate_stored_expression`` uses for Jinja blocks.
+
+ :param standin: what to substitute. `placeholder_is_executable` passes
+ `_PLACEHOLDER_STANDIN` to find out where the placeholder landed.
+ """
+ # Substituted through a function so `standin` is taken literally. As a
+ # replacement *string* `re.sub` would read backslashes in it as escapes,
+ # and `build_probe_sql` passes rendered SQL here: a filter value containing
+ # `\n` would probe a newline instead of the two characters the predicate
+ # compares, and one containing `\1` would raise outright.
+ return VALUE_PLACEHOLDER_RE.sub(lambda _: standin, transform)
+
+
+#: Prefix the transform is wrapped in before parsing. Its length is subtracted
+#: from any reported column so positions refer to what the owner actually
typed.
+_SELECT_PREFIX = "SELECT "
+
+
+def _parse_skeleton(
+ transform: str, engine: str, standin: str = _PARSE_STANDIN
+) -> SQLStatement | None:
+ """
+ Parse ``SELECT <transform>`` with the placeholder substituted out.
+
+ Returns ``None`` when the transform does not parse.
+ """
+ try:
+ return SQLStatement(
+ f"{_SELECT_PREFIX}{parse_skeleton(transform, standin)}", engine
+ )
+ except SupersetParseError:
+ return None
+
+
+def parse_error_detail(transform: str, engine: str) -> str | None:
+ """
+ Where the parser gave up on the transform.
+
+ Returns ``None`` when it parses, or when the parser offered no position.
+ Note that sqlglot parses unknown functions happily -- a misspelled function
+ name is not a parse error, it is an engine error, and surfaces only when
the
+ transform is evaluated.
+
+ The parser's own ``highlight`` is deliberately dropped: it would name the
+ ``NULL`` we substituted for ``:value``, which is not a token the owner
typed.
+ """
+ try:
+ SQLStatement(f"{_SELECT_PREFIX}{parse_skeleton(transform)}", engine)
+ except SupersetParseError as ex:
+ column = (ex.error.extra or {}).get("column")
+ if not isinstance(column, int):
+ return None
+ return str(
+ _(
+ "syntax error at position %(position)d.",
+ position=_position_in_transform(transform, column),
+ )
+ )
+ return None
+
+
+def _position_in_transform(transform: str, parsed_column: int) -> int:
+ """
+ Map a column in the parsed skeleton back to the transform as typed.
+
+ Two substitutions stand between them: the ``SELECT`` prefix, and every
+ ``:value`` that became a shorter ``NULL``. Without unwinding both, a
+ reported position drifts left by two characters per placeholder ahead of it
+ -- which is worst exactly where transforms usually break, at the end.
+ """
+ position = max(parsed_column - len(_SELECT_PREFIX), 0)
+ shift = len(":value") - len(_PARSE_STANDIN)
+ preceding = sum(
+ 1
+ for index, match in enumerate(VALUE_PLACEHOLDER_RE.finditer(transform))
+ if match.start() - index * shift < position
+ )
+ return position + preceding * shift
+
+
+def placeholder_is_executable(transform: str | None, engine: str) -> bool:
+ """
+ Whether every ``:value`` sits where the engine will evaluate it.
+
+ `contains_value_placeholder` is a regex over raw text, and `parse_skeleton`
+ substitutes before parsing, so neither notices a placeholder that is not in
+ an executable position. Two shapes reach the probe that way, and both are
+ worse than the inactive mapping a malformed transform earns:
+
+ ``':value'`` -- the placeholder inside a string literal. `build_probe_sql`
+ binds it anyway, because SQLAlchemy's own ``text()`` scan is no more
+ literal-aware than the regex, and the dialect then renders the bind
+ *including its own quotes* in the middle of the owner's quotes. A value of
+ ``" || (SELECT secret FROM vault LIMIT 1) || "`` closes the literal and
+ compiles to a working sub-query -- the very read primitive
+ `stored_expression_error` refuses when it is written openly.
+
+ ``1 -- :value`` -- the placeholder inside a comment. The probe's selections
+ are joined on one line, so the comment swallows its own ``AS v0`` alias and
+ everything after it; a single-value probe still returns one column, the
+ constant is accepted as the transform's result, and the mirror then emits
+ ``partition_col = <constant>`` for every filter value. That is wrong rows,
+ not lost pruning.
+
+ Answered structurally: substitute an identifier rather than a keyword and
+ count the column references it produced. A literal holds no column
+ reference and a comment is not parsed at all, so either case comes back
+ short of the number of placeholders the owner wrote.
+
+ Which is why a transform naming the stand-in itself is refused outright.
The
+ count is the whole gate, and a hand-written occurrence pays the difference:
+ ``concat(superset_pfm_value_standin, ':value')`` has one placeholder,
inside
+ a literal that contributes nothing, and one bare reference the owner wrote
--
+ so the counts match and the gate passes a placeholder the engine will never
+ evaluate. The probe then renders the bound value inside the owner's quotes,
+ where a value closing the literal can alias a column of any table the
+ connection can read into the stand-in's name and have the probe hand it
back
+ through the preview. There is no legitimate transform naming this
identifier,
+ so refusing it costs nothing and makes the count mean what it claims.
+ """
+ if not transform:
+ return False
+ if _PLACEHOLDER_STANDIN in transform.lower():
+ # Lowercased on both sides because `count_bare_column_references` is
+ # case-insensitive too: a dialect may normalize an unquoted identifier,
+ # so `SUPERSET_PFM_VALUE_STANDIN` would otherwise balance the count
+ # while slipping past a case-sensitive check here.
+ return False
+ expected = len(VALUE_PLACEHOLDER_RE.findall(transform))
+ if not expected:
+ return False
+ statement = _parse_skeleton(transform, engine, _PLACEHOLDER_STANDIN)
+ if statement is None:
+ return False
+ return statement.count_bare_column_references(_PLACEHOLDER_STANDIN) ==
expected
+
+
+def is_parseable(transform: str | None, engine: str) -> bool:
+ """
+ Whether the transform parses as a single select expression.
+
+ "Single" is the load-bearing word. `SELECT lower(:value), 'x'` parses just
+ as happily as `SELECT lower(:value)`, but it returns two columns per input
+ value, and the probe reads one column per input -- so an `IN` filter would
+ get a predicate built from the wrong halves of the wrong rows. Rejecting
the
+ list here is what lets the probe trust its own column count.
+ """
+ if not transform or not transform.strip():
+ return False
+ statement = _parse_skeleton(transform, engine)
+ return statement is not None and statement.count_select_expressions() == 1
+
+
+def is_bare_expression(transform: str | None, engine: str) -> bool:
+ """
+ Whether the transform is a scalar expression and nothing more.
+
+ `is_parseable` is not enough, because it counts only the projection.
+ ``secret || :value FROM vault`` holds exactly one select expression, so it
+ parses as "a single expression" -- and `build_probe_sql` then emits
+ ``SELECT secret || 'us' AS v0``, where its own alias is read as a table
+ alias on the FROM clause the transform smuggled in. The probe reads a
+ column the owner was never granted and hands it back through the predicate
+ the preview panel renders.
+
+ A transform is a scalar function of ``:value`` by definition -- the whole
+ feature rests on ``partition_col = T(mapped_col)``, which only type-checks
+ for scalar ``T`` -- so there is no legitimate transform with a clause of
+ its own, and none with a sub-query either.
+ """
+ if not transform or not transform.strip():
+ return False
+ statement = _parse_skeleton(transform, engine)
+ return (
+ statement is not None
+ and statement.is_bare_select_expression()
+ and not statement.has_subquery()
+ )
+
+
+def is_unfinished(transform: str | None, engine: str) -> bool:
+ """
+ Whether the transform is not SQL yet, as opposed to the wrong SQL.
+
+ The distinction matters because the two deserve opposite treatment. A
+ half-typed ``unix_timestamp(:value`` is what a text input produces on the
+ way to something valid: a PUT stores it and reports the mapping inactive,
+ so discarding it would mean an export could not round-trip the dataset it
+ came from. ``unix_timestamp(:value); DROP TABLE t`` is not on the way to
+ anything, and has to be refused wherever it is offered.
+
+ Both fail `is_parseable`, and both fail to parse as a single *statement* --
+ so neither of those tells them apart. Parsing as a *script* does: the
+ multi-statement form is two valid statements, while unfinished text is no
+ statement at all.
+ """
+ if not transform or not transform.strip():
+ return False
+ try:
+ SQLScript(f"{_SELECT_PREFIX}{parse_skeleton(transform)}", engine)
+ except SupersetParseError:
+ return True
+ return False
+
+
+def find_non_deterministic_functions(transform: str, engine: str) -> set[str]:
+ """
+ Names of non-deterministic functions the transform calls.
+
+ ``UNIX_TIMESTAMP`` is only reported in its zero-argument form, which means
+ "now" on Hive and Impala; the one-argument form is the canonical temporal
+ transform and stays allowed.
+ """
+ statement = _parse_skeleton(transform, engine)
+ if statement is None:
+ return set()
+
+ found = {
+ name
+ for name in NON_DETERMINISTIC_FUNCTIONS
+ if statement.check_functions_present({name})
+ }
Review Comment:
MySQL also accepts `UTC_DATE`, `UTC_TIME` and `UTC_TIMESTAMP` without
parentheses, which parse as columns, so `datediff(UTC_DATE, :value)` passes
this gate.
```suggestion
found = {
name
for name in NON_DETERMINISTIC_FUNCTIONS
if statement.check_functions_present({name})
}
# MySQL also accepts these without parentheses, which parses as a column.
bare = {"utc_date", "utc_time", "utc_timestamp"} &
statement.get_column_names()
found |= {name.upper() for name in bare}
```
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