253 lines
8.0 KiB
Python
253 lines
8.0 KiB
Python
# This file is dual licensed under the terms of the Apache License, Version
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# 2.0, and the BSD License. See the LICENSE file in the root of this repository
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# for complete details.
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import operator
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import os
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import platform
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import sys
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from typing import Any, Callable, Dict, List, Optional, Tuple, Union
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from ._parser import (
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MarkerAtom,
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MarkerList,
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Op,
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Value,
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Variable,
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parse_marker as _parse_marker,
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)
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from ._tokenizer import ParserSyntaxError
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from .specifiers import InvalidSpecifier, Specifier
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from .utils import canonicalize_name
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__all__ = [
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"InvalidMarker",
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"UndefinedComparison",
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"UndefinedEnvironmentName",
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"Marker",
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"default_environment",
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]
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Operator = Callable[[str, str], bool]
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class InvalidMarker(ValueError):
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"""
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An invalid marker was found, users should refer to PEP 508.
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"""
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class UndefinedComparison(ValueError):
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"""
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An invalid operation was attempted on a value that doesn't support it.
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"""
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class UndefinedEnvironmentName(ValueError):
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"""
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A name was attempted to be used that does not exist inside of the
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environment.
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"""
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def _normalize_extra_values(results: Any) -> Any:
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"""
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Normalize extra values.
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"""
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if isinstance(results[0], tuple):
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lhs, op, rhs = results[0]
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if isinstance(lhs, Variable) and lhs.value == "extra":
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normalized_extra = canonicalize_name(rhs.value)
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rhs = Value(normalized_extra)
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elif isinstance(rhs, Variable) and rhs.value == "extra":
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normalized_extra = canonicalize_name(lhs.value)
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lhs = Value(normalized_extra)
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results[0] = lhs, op, rhs
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return results
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def _format_marker(
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marker: Union[List[str], MarkerAtom, str], first: Optional[bool] = True
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) -> str:
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assert isinstance(marker, (list, tuple, str))
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# Sometimes we have a structure like [[...]] which is a single item list
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# where the single item is itself it's own list. In that case we want skip
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# the rest of this function so that we don't get extraneous () on the
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# outside.
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if (
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isinstance(marker, list)
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and len(marker) == 1
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and isinstance(marker[0], (list, tuple))
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):
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return _format_marker(marker[0])
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if isinstance(marker, list):
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inner = (_format_marker(m, first=False) for m in marker)
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if first:
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return " ".join(inner)
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else:
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return "(" + " ".join(inner) + ")"
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elif isinstance(marker, tuple):
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return " ".join([m.serialize() for m in marker])
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else:
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return marker
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_operators: Dict[str, Operator] = {
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"in": lambda lhs, rhs: lhs in rhs,
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"not in": lambda lhs, rhs: lhs not in rhs,
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"<": operator.lt,
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"<=": operator.le,
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"==": operator.eq,
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"!=": operator.ne,
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">=": operator.ge,
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">": operator.gt,
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}
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def _eval_op(lhs: str, op: Op, rhs: str) -> bool:
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try:
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spec = Specifier("".join([op.serialize(), rhs]))
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except InvalidSpecifier:
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pass
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else:
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return spec.contains(lhs, prereleases=True)
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oper: Optional[Operator] = _operators.get(op.serialize())
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if oper is None:
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raise UndefinedComparison(f"Undefined {op!r} on {lhs!r} and {rhs!r}.")
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return oper(lhs, rhs)
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def _normalize(*values: str, key: str) -> Tuple[str, ...]:
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# PEP 685 – Comparison of extra names for optional distribution dependencies
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# https://peps.python.org/pep-0685/
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# > When comparing extra names, tools MUST normalize the names being
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# > compared using the semantics outlined in PEP 503 for names
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if key == "extra":
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return tuple(canonicalize_name(v) for v in values)
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# other environment markers don't have such standards
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return values
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def _evaluate_markers(markers: MarkerList, environment: Dict[str, str]) -> bool:
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groups: List[List[bool]] = [[]]
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for marker in markers:
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assert isinstance(marker, (list, tuple, str))
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if isinstance(marker, list):
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groups[-1].append(_evaluate_markers(marker, environment))
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elif isinstance(marker, tuple):
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lhs, op, rhs = marker
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if isinstance(lhs, Variable):
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environment_key = lhs.value
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lhs_value = environment[environment_key]
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rhs_value = rhs.value
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else:
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lhs_value = lhs.value
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environment_key = rhs.value
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rhs_value = environment[environment_key]
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lhs_value, rhs_value = _normalize(lhs_value, rhs_value, key=environment_key)
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groups[-1].append(_eval_op(lhs_value, op, rhs_value))
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else:
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assert marker in ["and", "or"]
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if marker == "or":
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groups.append([])
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return any(all(item) for item in groups)
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def format_full_version(info: "sys._version_info") -> str:
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version = "{0.major}.{0.minor}.{0.micro}".format(info)
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kind = info.releaselevel
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if kind != "final":
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version += kind[0] + str(info.serial)
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return version
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def default_environment() -> Dict[str, str]:
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iver = format_full_version(sys.implementation.version)
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implementation_name = sys.implementation.name
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return {
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"implementation_name": implementation_name,
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"implementation_version": iver,
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"os_name": os.name,
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"platform_machine": platform.machine(),
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"platform_release": platform.release(),
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"platform_system": platform.system(),
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"platform_version": platform.version(),
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"python_full_version": platform.python_version(),
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"platform_python_implementation": platform.python_implementation(),
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"python_version": ".".join(platform.python_version_tuple()[:2]),
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"sys_platform": sys.platform,
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}
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class Marker:
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def __init__(self, marker: str) -> None:
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# Note: We create a Marker object without calling this constructor in
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# packaging.requirements.Requirement. If any additional logic is
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# added here, make sure to mirror/adapt Requirement.
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try:
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self._markers = _normalize_extra_values(_parse_marker(marker))
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# The attribute `_markers` can be described in terms of a recursive type:
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# MarkerList = List[Union[Tuple[Node, ...], str, MarkerList]]
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#
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# For example, the following expression:
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# python_version > "3.6" or (python_version == "3.6" and os_name == "unix")
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#
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# is parsed into:
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# [
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# (<Variable('python_version')>, <Op('>')>, <Value('3.6')>),
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# 'and',
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# [
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# (<Variable('python_version')>, <Op('==')>, <Value('3.6')>),
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# 'or',
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# (<Variable('os_name')>, <Op('==')>, <Value('unix')>)
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# ]
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# ]
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except ParserSyntaxError as e:
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raise InvalidMarker(str(e)) from e
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def __str__(self) -> str:
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return _format_marker(self._markers)
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def __repr__(self) -> str:
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return f"<Marker('{self}')>"
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def __hash__(self) -> int:
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return hash((self.__class__.__name__, str(self)))
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def __eq__(self, other: Any) -> bool:
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if not isinstance(other, Marker):
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return NotImplemented
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return str(self) == str(other)
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def evaluate(self, environment: Optional[Dict[str, str]] = None) -> bool:
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"""Evaluate a marker.
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Return the boolean from evaluating the given marker against the
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environment. environment is an optional argument to override all or
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part of the determined environment.
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The environment is determined from the current Python process.
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"""
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current_environment = default_environment()
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current_environment["extra"] = ""
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if environment is not None:
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current_environment.update(environment)
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# The API used to allow setting extra to None. We need to handle this
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# case for backwards compatibility.
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if current_environment["extra"] is None:
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current_environment["extra"] = ""
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return _evaluate_markers(self._markers, current_environment)
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