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#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2020 The Matrix.org Foundation C.I.C.
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
from types import TracebackType
from typing import (
Any,
Callable,
Iterator,
Mapping,
Protocol,
Sequence,
)
"""
Some very basic protocol definitions for the DB-API2 classes specified in PEP-249
"""
SQLQueryParameters = Sequence[Any] | Mapping[str, Any]
class Cursor(Protocol):
def execute(self, sql: str, parameters: SQLQueryParameters = ...) -> Any: ...
def executemany(
self, sql: str, parameters: Sequence[SQLQueryParameters]
) -> Any: ...
def fetchone(self) -> tuple | None: ...
def fetchmany(self, size: int | None = ...) -> list[tuple]: ...
def fetchall(self) -> list[tuple]: ...
@property
def description(
self,
) -> Sequence[Any] | None:
# At the time of writing, Synapse only assumes that `column[0]: str` for each
# `column in description`. Since this is hard to express in the type system, and
# as this is rarely used in Synapse, we deem `column: Any` good enough.
...
@property
def rowcount(self) -> int:
return 0
def __iter__(self) -> Iterator[tuple]: ...
def close(self) -> None: ...
class Connection(Protocol):
def cursor(self) -> Cursor: ...
def close(self) -> None: ...
def commit(self) -> None: ...
def rollback(self) -> None: ...
def __enter__(self) -> "Connection": ...
def __exit__(
self,
exc_type: type[BaseException] | None,
exc_value: BaseException | None,
traceback: TracebackType | None,
) -> bool | None: ...
class DBAPI2Module(Protocol):
"""The module-level attributes that we use from PEP 249.
This is NOT a comprehensive stub for the entire DBAPI2."""
__name__: str
# Exceptions. See https://peps.python.org/pep-0249/#exceptions
# For our specific drivers:
# - Python's sqlite3 module doesn't contains the same descriptions as the
# DBAPI2 spec, see https://docs.python.org/3/library/sqlite3.html#exceptions
# - Psycopg2 maps every Postgres error code onto a unique exception class which
# extends from this hierarchy. See
# https://docs.python.org/3/library/sqlite3.html?highlight=sqlite3#exceptions
# https://www.postgresql.org/docs/current/errcodes-appendix.html#ERRCODES-TABLE
#
# Note: rather than
# x: T
# we write
# @property
# def x(self) -> T: ...
# which expresses that the protocol attribute `x` is read-only. The mypy docs
# https://mypy.readthedocs.io/en/latest/common_issues.html#covariant-subtyping-of-mutable-protocol-members-is-rejected
# explain why this is necessary for safety. TL;DR: we shouldn't be able to write
# to `x`, only read from it. See also https://github.com/python/mypy/issues/6002 .
@property
def Warning(self) -> type[Exception]: ...
@property
def Error(self) -> type[Exception]: ...
# Errors are divided into `InterfaceError`s (something went wrong in the database
# driver) and `DatabaseError`s (something went wrong in the database). These are
# both subclasses of `Error`, but we can't currently express this in type
# annotations due to https://github.com/python/mypy/issues/8397
@property
def InterfaceError(self) -> type[Exception]: ...
@property
def DatabaseError(self) -> type[Exception]: ...
# Everything below is a subclass of `DatabaseError`.
# Roughly: the database rejected a nonsensical value. Examples:
# - An integer was too big for its data type.
# - An invalid date time was provided.
# - A string contained a null code point.
@property
def DataError(self) -> type[Exception]: ...
# Roughly: something went wrong in the database, but it's not within the application
# programmer's control. Examples:
# - We failed to establish a connection to the database.
# - The connection to the database was lost.
# - A deadlock was detected.
# - A serialisation failure occurred.
# - The database ran out of resources, such as storage, memory, connections, etc.
# - The database encountered an error from the operating system.
@property
def OperationalError(self) -> type[Exception]: ...
# Roughly: we've given the database data which breaks a rule we asked it to enforce.
# Examples:
# - Stop, criminal scum! You violated the foreign key constraint
# - Also check constraints, non-null constraints, etc.
@property
def IntegrityError(self) -> type[Exception]: ...
# Roughly: something went wrong within the database server itself.
@property
def InternalError(self) -> type[Exception]: ...
# Roughly: the application did something silly that needs to be fixed. Examples:
# - We don't have permissions to do something.
# - We tried to create a table with duplicate column names.
# - We tried to use a reserved name.
# - We referred to a column that doesn't exist.
@property
def ProgrammingError(self) -> type[Exception]: ...
# Roughly: we've tried to do something that this database doesn't support.
@property
def NotSupportedError(self) -> type[Exception]: ...
# We originally wrote
# def connect(self, *args, **kwargs) -> Connection: ...
# But mypy doesn't seem to like that because sqlite3.connect takes a mandatory
# positional argument. We can't make that part of the signature though, because
# psycopg2.connect doesn't have a mandatory positional argument. Instead, we use
# the following slightly unusual workaround.
@property
def connect(self) -> Callable[..., Connection]: ...
__all__ = ["Cursor", "Connection", "DBAPI2Module"]
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