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