JezK
Edit File: pyproject.py
import importlib.util import os from collections import namedtuple from typing import Any, List, Optional from pip._vendor import tomli from pip._vendor.packaging.requirements import InvalidRequirement, Requirement from pip._internal.exceptions import ( InstallationError, InvalidPyProjectBuildRequires, MissingPyProjectBuildRequires, ) def _is_list_of_str(obj: Any) -> bool: return isinstance(obj, list) and all(isinstance(item, str) for item in obj) def make_pyproject_path(unpacked_source_directory: str) -> str: return os.path.join(unpacked_source_directory, "pyproject.toml") BuildSystemDetails = namedtuple( "BuildSystemDetails", ["requires", "backend", "check", "backend_path"] ) def load_pyproject_toml( use_pep517: Optional[bool], pyproject_toml: str, setup_py: str, req_name: str ) -> Optional[BuildSystemDetails]: """Load the pyproject.toml file. Parameters: use_pep517 - Has the user requested PEP 517 processing? None means the user hasn't explicitly specified. pyproject_toml - Location of the project's pyproject.toml file setup_py - Location of the project's setup.py file req_name - The name of the requirement we're processing (for error reporting) Returns: None if we should use the legacy code path, otherwise a tuple ( requirements from pyproject.toml, name of PEP 517 backend, requirements we should check are installed after setting up the build environment directory paths to import the backend from (backend-path), relative to the project root. ) """ has_pyproject = os.path.isfile(pyproject_toml) has_setup = os.path.isfile(setup_py) if not has_pyproject and not has_setup: raise InstallationError( f"{req_name} does not appear to be a Python project: " f"neither 'setup.py' nor 'pyproject.toml' found." ) if has_pyproject: with open(pyproject_toml, encoding="utf-8") as f: pp_toml = tomli.loads(f.read()) build_system = pp_toml.get("build-system") else: build_system = None # The following cases must use PEP 517 # We check for use_pep517 being non-None and falsey because that means # the user explicitly requested --no-use-pep517. The value 0 as # opposed to False can occur when the value is provided via an # environment variable or config file option (due to the quirk of # strtobool() returning an integer in pip's configuration code). if has_pyproject and not has_setup: if use_pep517 is not None and not use_pep517: raise InstallationError( "Disabling PEP 517 processing is invalid: " "project does not have a setup.py" ) use_pep517 = True elif build_system and "build-backend" in build_system: if use_pep517 is not None and not use_pep517: raise InstallationError( "Disabling PEP 517 processing is invalid: " "project specifies a build backend of {} " "in pyproject.toml".format(build_system["build-backend"]) ) use_pep517 = True # If we haven't worked out whether to use PEP 517 yet, # and the user hasn't explicitly stated a preference, # we do so if the project has a pyproject.toml file # or if we cannot import setuptools. # We fallback to PEP 517 when without setuptools, # so setuptools can be installed as a default build backend. # For more info see: # https://discuss.python.org/t/pip-without-setuptools-could-the-experience-be-improved/11810/9 elif use_pep517 is None: use_pep517 = has_pyproject or not importlib.util.find_spec("setuptools") # At this point, we know whether we're going to use PEP 517. assert use_pep517 is not None # If we're using the legacy code path, there is nothing further # for us to do here. if not use_pep517: return None if build_system is None: # Either the user has a pyproject.toml with no build-system # section, or the user has no pyproject.toml, but has opted in # explicitly via --use-pep517. # In the absence of any explicit backend specification, we # assume the setuptools backend that most closely emulates the # traditional direct setup.py execution, and require wheel and # a version of setuptools that supports that backend. build_system = { "requires": ["setuptools>=40.8.0", "wheel"], "build-backend": "setuptools.build_meta:__legacy__", } # If we're using PEP 517, we have build system information (either # from pyproject.toml, or defaulted by the code above). # Note that at this point, we do not know if the user has actually # specified a backend, though. assert build_system is not None # Ensure that the build-system section in pyproject.toml conforms # to PEP 518. # Specifying the build-system table but not the requires key is invalid if "requires" not in build_system: raise MissingPyProjectBuildRequires(package=req_name) # Error out if requires is not a list of strings requires = build_system["requires"] if not _is_list_of_str(requires): raise InvalidPyProjectBuildRequires( package=req_name, reason="It is not a list of strings.", ) # Each requirement must be valid as per PEP 508 for requirement in requires: try: Requirement(requirement) except InvalidRequirement as error: raise InvalidPyProjectBuildRequires( package=req_name, reason=f"It contains an invalid requirement: {requirement!r}", ) from error backend = build_system.get("build-backend") backend_path = build_system.get("backend-path", []) check: List[str] = [] if backend is None: # If the user didn't specify a backend, we assume they want to use # the setuptools backend. But we can't be sure they have included # a version of setuptools which supplies the backend. So we # make a note to check that this requirement is present once # we have set up the environment. # This is quite a lot of work to check for a very specific case. But # the problem is, that case is potentially quite common - projects that # adopted PEP 518 early for the ability to specify requirements to # execute setup.py, but never considered needing to mention the build # tools themselves. The original PEP 518 code had a similar check (but # implemented in a different way). backend = "setuptools.build_meta:__legacy__" check = ["setuptools>=40.8.0"] return BuildSystemDetails(requires, backend, check, backend_path)