rusackas commented on code in PR #41803: URL: https://github.com/apache/superset/pull/41803#discussion_r3533009033
########## superset/sql/dialects/trino.py: ########## @@ -0,0 +1,273 @@ +# 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 typing as t + +from sqlglot import exp +from sqlglot.dialects.trino import Trino as SqlglotTrino +from sqlglot.tokens import Token, TokenType + +# Keywords that open a block terminated by ``END`` in Trino SQL routines +# (https://trino.io/docs/current/udf/sql.html). ``CASE`` is included because +# both the ``CASE`` statement and the ``CASE`` expression are terminated by +# ``END``, so counting them keeps the depth balanced either way. +BLOCK_OPENERS = {"BEGIN", "CASE", "IF", "LOOP", "REPEAT", "WHILE"} + +# Keywords that are also scalar functions in Trino (e.g. ``IF(a, b, c)`` and +# ``REPEAT('a', 3)``). When immediately followed by ``(`` they are function +# calls, not block openers. +AMBIGUOUS_OPENERS = {"IF", "REPEAT"} + +BODY_KEYWORDS = ("RETURN", "BEGIN") Review Comment: Added `tuple[str, str]` annotation. ########## superset/sql/dialects/trino.py: ########## @@ -0,0 +1,273 @@ +# 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 typing as t + +from sqlglot import exp +from sqlglot.dialects.trino import Trino as SqlglotTrino +from sqlglot.tokens import Token, TokenType + +# Keywords that open a block terminated by ``END`` in Trino SQL routines +# (https://trino.io/docs/current/udf/sql.html). ``CASE`` is included because +# both the ``CASE`` statement and the ``CASE`` expression are terminated by +# ``END``, so counting them keeps the depth balanced either way. +BLOCK_OPENERS = {"BEGIN", "CASE", "IF", "LOOP", "REPEAT", "WHILE"} + +# Keywords that are also scalar functions in Trino (e.g. ``IF(a, b, c)`` and +# ``REPEAT('a', 3)``). When immediately followed by ``(`` they are function +# calls, not block openers. +AMBIGUOUS_OPENERS = {"IF", "REPEAT"} + +BODY_KEYWORDS = ("RETURN", "BEGIN") + + +class InlineUDF(exp.CTE): + """ + An inline SQL user-defined function declared in a ``WITH`` clause. + + Trino supports declaring UDFs inline as part of a query:: + + WITH FUNCTION meaning_of_life() + RETURNS tinyint + BEGIN + DECLARE a tinyint DEFAULT CAST(6 AS tinyint); + DECLARE b tinyint DEFAULT CAST(7 AS tinyint); + RETURN a * b; + END + SELECT meaning_of_life() + + The function definition is stored verbatim as an opaque string (wrapped + in an ``exp.Var`` so that AST traversal helpers see an expression), since + sqlglot has no representation for SQL routine bodies. Trino does not + allow queries inside SQL UDF bodies, so no table references are hidden + by the opaque representation. + + This subclasses ``exp.CTE`` because ``sqlglot.parser.Parser._parse_with`` + only collects ``exp.CTE`` instances into the ``WITH`` clause. + """ + + arg_types = {"this": True} + + +class Trino(SqlglotTrino): + """ + Custom Trino dialect with support for inline SQL UDFs. + + sqlglot cannot parse Trino SQL routine syntax; see + https://github.com/tobymao/sqlglot/issues/5178. There are two separate + problems: + + 1. The parser splits statements on every semicolon, including the ones + inside a ``BEGIN ... END`` routine body. + 2. The ``FUNCTION`` specification in a ``WITH`` clause is not valid CTE + syntax. + + This dialect keeps routine bodies intact when splitting statements, and + parses inline function specifications into opaque `InlineUDF` nodes that + regenerate verbatim. + + Note that sqlglot's ``Dialect`` metaclass registers subclasses by class + name, so once this module is imported this class also replaces the + built-in dialect for string-based lookups (``dialect="trino"``). This is + intentional, and consistent with how other Superset dialects (e.g. + ``Dremio``) shadow their sqlglot counterparts: the extensions are purely + additive, only activating on syntax that fails to parse upstream. + """ + + class Parser(SqlglotTrino.Parser): + @staticmethod + def _block_depth_delta( + text: str, + prev_text: str, + next_token: Token | None, + ) -> int: + """ + Compute the block nesting change contributed by a routine token. + """ + if text in BLOCK_OPENERS: + if prev_text == "END": + return 0 # block terminator, e.g. `END IF`, `END CASE` + if ( + text in AMBIGUOUS_OPENERS + and next_token + and next_token.token_type == TokenType.L_PAREN + ): + return 0 # scalar function call, e.g. `IF(a, b, c)` + return 1 + if text == "END": + return -1 + return 0 + + def _parse( + self, + parse_method: t.Callable[..., exp.Expression | None], + raw_tokens: list[Token], + sql: str | None = None, + ) -> list[exp.Expression | None]: + """ + Split tokens into statements, keeping routine bodies intact. + + This is a copy of ``sqlglot.parser.Parser._parse`` with one + change: when a statement starts with ``WITH FUNCTION``, ``CREATE + FUNCTION``, or ``CREATE OR REPLACE FUNCTION``, semicolons inside + ``BEGIN ... END`` blocks do not split the statement. + """ + self.reset() + self.sql = sql or "" + + total = len(raw_tokens) + chunks: list[list[Token]] = [[]] + routine_mode = False + depth = 0 + prev_text = "" + Review Comment: Added `bool`/`int`/`str` annotations to `routine_mode`, `depth`, and `prev_text`. ########## superset/sql/dialects/trino.py: ########## @@ -0,0 +1,273 @@ +# 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 typing as t + +from sqlglot import exp +from sqlglot.dialects.trino import Trino as SqlglotTrino +from sqlglot.tokens import Token, TokenType + +# Keywords that open a block terminated by ``END`` in Trino SQL routines +# (https://trino.io/docs/current/udf/sql.html). ``CASE`` is included because +# both the ``CASE`` statement and the ``CASE`` expression are terminated by +# ``END``, so counting them keeps the depth balanced either way. +BLOCK_OPENERS = {"BEGIN", "CASE", "IF", "LOOP", "REPEAT", "WHILE"} + +# Keywords that are also scalar functions in Trino (e.g. ``IF(a, b, c)`` and +# ``REPEAT('a', 3)``). When immediately followed by ``(`` they are function +# calls, not block openers. +AMBIGUOUS_OPENERS = {"IF", "REPEAT"} + +BODY_KEYWORDS = ("RETURN", "BEGIN") + + +class InlineUDF(exp.CTE): + """ + An inline SQL user-defined function declared in a ``WITH`` clause. + + Trino supports declaring UDFs inline as part of a query:: + + WITH FUNCTION meaning_of_life() + RETURNS tinyint + BEGIN + DECLARE a tinyint DEFAULT CAST(6 AS tinyint); + DECLARE b tinyint DEFAULT CAST(7 AS tinyint); + RETURN a * b; + END + SELECT meaning_of_life() + + The function definition is stored verbatim as an opaque string (wrapped + in an ``exp.Var`` so that AST traversal helpers see an expression), since + sqlglot has no representation for SQL routine bodies. Trino does not + allow queries inside SQL UDF bodies, so no table references are hidden + by the opaque representation. + + This subclasses ``exp.CTE`` because ``sqlglot.parser.Parser._parse_with`` + only collects ``exp.CTE`` instances into the ``WITH`` clause. + """ + + arg_types = {"this": True} + + +class Trino(SqlglotTrino): + """ + Custom Trino dialect with support for inline SQL UDFs. + + sqlglot cannot parse Trino SQL routine syntax; see + https://github.com/tobymao/sqlglot/issues/5178. There are two separate + problems: + + 1. The parser splits statements on every semicolon, including the ones + inside a ``BEGIN ... END`` routine body. + 2. The ``FUNCTION`` specification in a ``WITH`` clause is not valid CTE + syntax. + + This dialect keeps routine bodies intact when splitting statements, and + parses inline function specifications into opaque `InlineUDF` nodes that + regenerate verbatim. + + Note that sqlglot's ``Dialect`` metaclass registers subclasses by class + name, so once this module is imported this class also replaces the + built-in dialect for string-based lookups (``dialect="trino"``). This is + intentional, and consistent with how other Superset dialects (e.g. + ``Dremio``) shadow their sqlglot counterparts: the extensions are purely + additive, only activating on syntax that fails to parse upstream. + """ + + class Parser(SqlglotTrino.Parser): + @staticmethod + def _block_depth_delta( + text: str, + prev_text: str, + next_token: Token | None, + ) -> int: + """ + Compute the block nesting change contributed by a routine token. + """ + if text in BLOCK_OPENERS: + if prev_text == "END": + return 0 # block terminator, e.g. `END IF`, `END CASE` + if ( + text in AMBIGUOUS_OPENERS + and next_token + and next_token.token_type == TokenType.L_PAREN + ): + return 0 # scalar function call, e.g. `IF(a, b, c)` + return 1 + if text == "END": + return -1 + return 0 + + def _parse( + self, + parse_method: t.Callable[..., exp.Expression | None], + raw_tokens: list[Token], + sql: str | None = None, + ) -> list[exp.Expression | None]: + """ + Split tokens into statements, keeping routine bodies intact. + + This is a copy of ``sqlglot.parser.Parser._parse`` with one + change: when a statement starts with ``WITH FUNCTION``, ``CREATE + FUNCTION``, or ``CREATE OR REPLACE FUNCTION``, semicolons inside + ``BEGIN ... END`` blocks do not split the statement. + """ + self.reset() + self.sql = sql or "" + + total = len(raw_tokens) + chunks: list[list[Token]] = [[]] + routine_mode = False + depth = 0 + prev_text = "" + + for i, token in enumerate(raw_tokens): + if token.token_type == TokenType.SEMICOLON and depth <= 0: + if token.comments: + chunks.append([token]) + if i < total - 1: + chunks.append([]) + routine_mode = False + depth = 0 + prev_text = "" + continue + + chunk = chunks[-1] + chunk.append(token) + + if token.token_type == TokenType.FUNCTION and not routine_mode: + heads = [tok.token_type for tok in chunk[:-1]] + routine_mode = heads in ( + [TokenType.WITH], + [TokenType.CREATE], + [TokenType.CREATE, TokenType.OR, TokenType.REPLACE], + ) + elif routine_mode: + text = token.text.upper() + next_token = raw_tokens[i + 1] if i < total - 1 else None + depth += self._block_depth_delta(text, prev_text, next_token) + + prev_text = token.text.upper() + + self._chunks = chunks + return self._parse_batch_statements( + parse_method=parse_method, + sep_first_statement=False, + ) + + def _parse_cte(self) -> exp.CTE | None: + """ + Parse a single entry in a ``WITH`` clause. + + An entry starting with the ``FUNCTION`` keyword followed by an + identifier is an inline UDF specification; anything else + (including a CTE named "function") is handled by sqlglot. + """ + if ( + self._curr + and self._curr.token_type == TokenType.FUNCTION + and self._next + and self._next.token_type + not in (TokenType.ALIAS, TokenType.L_PAREN, TokenType.COMMA) + ): + return self._parse_inline_udf() + + return super()._parse_cte() + + def _parse_inline_udf(self) -> InlineUDF: + """ + Consume an inline UDF specification and return it verbatim. + + The specification is ``FUNCTION name(params) RETURNS type`` plus + optional routine characteristics, followed by a body that is + either ``RETURN expression`` or a ``BEGIN ... END`` block. + """ + start = self._curr + self._advance() + + # scan for the start of the function body, skipping over the + # signature, return type, and routine characteristics + paren_depth = 0 + body: str | None = None Review Comment: Added `int` annotation. ########## tests/unit_tests/sql/dialects/trino_tests.py: ########## @@ -0,0 +1,239 @@ +# 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. + +import pytest +import sqlglot + +from superset.exceptions import SupersetParseError +from superset.sql.dialects.trino import InlineUDF, Trino +from superset.sql.parse import SQLScript, SQLStatement, Table + +# example from https://trino.io/docs/current/udf/sql/begin.html, reported in +# https://github.com/apache/superset/issues/26162 +INLINE_UDF = """ Review Comment: Added `str` annotation. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
