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- # 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.
- from __future__ import annotations
- import operator
- import os
- import platform
- import sys
- from typing import AbstractSet, Any, Callable, Literal, TypedDict, Union, cast
- from ._parser import MarkerAtom, MarkerList, Op, Value, Variable
- from ._parser import parse_marker as _parse_marker
- from ._tokenizer import ParserSyntaxError
- from .specifiers import InvalidSpecifier, Specifier
- from .utils import canonicalize_name
- __all__ = [
- "EvaluateContext",
- "InvalidMarker",
- "Marker",
- "UndefinedComparison",
- "UndefinedEnvironmentName",
- "default_environment",
- ]
- Operator = Callable[[str, Union[str, AbstractSet[str]]], bool]
- EvaluateContext = Literal["metadata", "lock_file", "requirement"]
- MARKERS_ALLOWING_SET = {"extras", "dependency_groups"}
- 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.
- """
- class Environment(TypedDict):
- implementation_name: str
- """The implementation's identifier, e.g. ``'cpython'``."""
- implementation_version: str
- """
- The implementation's version, e.g. ``'3.13.0a2'`` for CPython 3.13.0a2, or
- ``'7.3.13'`` for PyPy3.10 v7.3.13.
- """
- os_name: str
- """
- The value of :py:data:`os.name`. The name of the operating system dependent module
- imported, e.g. ``'posix'``.
- """
- platform_machine: str
- """
- Returns the machine type, e.g. ``'i386'``.
- An empty string if the value cannot be determined.
- """
- platform_release: str
- """
- The system's release, e.g. ``'2.2.0'`` or ``'NT'``.
- An empty string if the value cannot be determined.
- """
- platform_system: str
- """
- The system/OS name, e.g. ``'Linux'``, ``'Windows'`` or ``'Java'``.
- An empty string if the value cannot be determined.
- """
- platform_version: str
- """
- The system's release version, e.g. ``'#3 on degas'``.
- An empty string if the value cannot be determined.
- """
- python_full_version: str
- """
- The Python version as string ``'major.minor.patchlevel'``.
- Note that unlike the Python :py:data:`sys.version`, this value will always include
- the patchlevel (it defaults to 0).
- """
- platform_python_implementation: str
- """
- A string identifying the Python implementation, e.g. ``'CPython'``.
- """
- python_version: str
- """The Python version as string ``'major.minor'``."""
- sys_platform: str
- """
- This string contains a platform identifier that can be used to append
- platform-specific components to :py:data:`sys.path`, for instance.
- For Unix systems, except on Linux and AIX, this is the lowercased OS name as
- returned by ``uname -s`` with the first part of the version as returned by
- ``uname -r`` appended, e.g. ``'sunos5'`` or ``'freebsd8'``, at the time when Python
- was built.
- """
- 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: list[str] | MarkerAtom | str, first: bool | None = 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 | AbstractSet[str]) -> bool:
- if isinstance(rhs, str):
- try:
- spec = Specifier("".join([op.serialize(), rhs]))
- except InvalidSpecifier:
- pass
- else:
- return spec.contains(lhs, prereleases=True)
- oper: Operator | None = _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(
- lhs: str, rhs: str | AbstractSet[str], key: str
- ) -> tuple[str, str | AbstractSet[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":
- assert isinstance(rhs, str), "extra value must be a string"
- return (canonicalize_name(lhs), canonicalize_name(rhs))
- if key in MARKERS_ALLOWING_SET:
- if isinstance(rhs, str): # pragma: no cover
- return (canonicalize_name(lhs), canonicalize_name(rhs))
- else:
- return (canonicalize_name(lhs), {canonicalize_name(v) for v in rhs})
- # other environment markers don't have such standards
- return lhs, rhs
- def _evaluate_markers(
- markers: MarkerList, environment: dict[str, str | AbstractSet[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]
- assert isinstance(lhs_value, str), "lhs must be a string"
- 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 = f"{info.major}.{info.minor}.{info.micro}"
- kind = info.releaselevel
- if kind != "final":
- version += kind[0] + str(info.serial)
- return version
- def default_environment() -> Environment:
- 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:
- # [
- # (<Variable('python_version')>, <Op('>')>, <Value('3.6')>),
- # 'and',
- # [
- # (<Variable('python_version')>, <Op('==')>, <Value('3.6')>),
- # 'or',
- # (<Variable('os_name')>, <Op('==')>, <Value('unix')>)
- # ]
- # ]
- 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"<Marker('{self}')>"
- 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: dict[str, str] | None = None,
- context: EvaluateContext = "metadata",
- ) -> 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 *context* parameter specifies what
- context the markers are being evaluated for, which influences what markers
- are considered valid. Acceptable values are "metadata" (for core metadata;
- default), "lock_file", and "requirement" (i.e. all other situations).
- The environment is determined from the current Python process.
- """
- current_environment = cast(
- "dict[str, str | AbstractSet[str]]", default_environment()
- )
- if context == "lock_file":
- current_environment.update(
- extras=frozenset(), dependency_groups=frozenset()
- )
- elif context == "metadata":
- 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 "extra" in current_environment and current_environment["extra"] is None:
- current_environment["extra"] = ""
- return _evaluate_markers(
- self._markers, _repair_python_full_version(current_environment)
- )
- def _repair_python_full_version(
- env: dict[str, str | AbstractSet[str]],
- ) -> dict[str, str | AbstractSet[str]]:
- """
- Work around platform.python_version() returning something that is not PEP 440
- compliant for non-tagged Python builds.
- """
- python_full_version = cast(str, env["python_full_version"])
- if python_full_version.endswith("+"):
- env["python_full_version"] = f"{python_full_version}local"
- return env
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