Nominatim/nominatim/typing.py

# SPDX-License-Identifier: GPL-2.0-only
#
# This file is part of Nominatim. (https://nominatim.org)
#
# Copyright (C) 2023 by the Nominatim developer community.
# For a full list of authors see the git log.
"""
Type definitions for typing annotations.

Complex type definitions are moved here, to keep the source files readable.
"""
from typing import Any, Union, Mapping, TypeVar, Sequence, TYPE_CHECKING

# Generics variable names do not confirm to naming styles, ignore globally here.
# pylint: disable=invalid-name,abstract-method,multiple-statements
# pylint: disable=missing-class-docstring,useless-import-alias

if TYPE_CHECKING:
    import psycopg2.sql
    import psycopg2.extensions
    import psycopg2.extras
    import os

StrPath = Union[str, 'os.PathLike[str]']

SysEnv = Mapping[str, str]

# psycopg2-related types

Query = Union[str, bytes, 'psycopg2.sql.Composable']

T_ResultKey = TypeVar('T_ResultKey', int, str)

class DictCursorResult(Mapping[str, Any]):
    def __getitem__(self, x: Union[int, str]) -> Any: ...

DictCursorResults = Sequence[DictCursorResult]

T_cursor = TypeVar('T_cursor', bound='psycopg2.extensions.cursor')

# The following typing features require typing_extensions to work
# on all supported Python versions.
# Only require this for type checking but not for normal operations.

if TYPE_CHECKING:
    from typing_extensions import (Protocol as Protocol,
                                   Final as Final,
                                   TypedDict as TypedDict)
else:
    Protocol = object
    Final = 'Final'
    TypedDict = dict


# SQLAlchemy introduced generic types in version 2.0 making typing
# incompatible with older versions. Add wrappers here so we don't have
# to litter the code with bare-string types.

if TYPE_CHECKING:
    import sqlalchemy as sa
    from typing_extensions import (TypeAlias as TypeAlias)
else:
    TypeAlias = str

SaSelect: TypeAlias = 'sa.Select[Any]'
SaRow: TypeAlias = 'sa.Row[Any]'
SaColumn: TypeAlias = 'sa.ColumnElement[Any]'
SaLabel: TypeAlias = 'sa.Label[Any]'
SaFromClause: TypeAlias = 'sa.FromClause'
SaSelectable: TypeAlias = 'sa.Selectable'