from __future__ import absolute_import import io import os import sys from collections import namedtuple from pip._vendor import six, toml from pip._vendor.packaging.requirements import InvalidRequirement, Requirement from pip._internal.exceptions import InstallationError from pip._internal.utils.typing import MYPY_CHECK_RUNNING if MYPY_CHECK_RUNNING: from typing import Any, Optional, List def _is_list_of_str(obj): # type: (Any) -> bool return ( isinstance(obj, list) and all(isinstance(item, six.string_types) for item in obj) ) def make_pyproject_path(unpacked_source_directory): # type: (str) -> str path = os.path.join(unpacked_source_directory, 'pyproject.toml') # Python2 __file__ should not be unicode if six.PY2 and isinstance(path, six.text_type): path = path.encode(sys.getfilesystemencoding()) return path BuildSystemDetails = namedtuple('BuildSystemDetails', [ 'requires', 'backend', 'check', 'backend_path' ]) def load_pyproject_toml( use_pep517, # type: Optional[bool] pyproject_toml, # type: str setup_py, # type: str req_name # type: str ): # type: (...) -> 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 has_pyproject: with io.open(pyproject_toml, encoding="utf-8") as f: pp_toml = toml.load(f) 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. elif use_pep517 is None: use_pep517 = has_pyproject # 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. error_template = ( "{package} has a pyproject.toml file that does not comply " "with PEP 518: {reason}" ) # Specifying the build-system table but not the requires key is invalid if "requires" not in build_system: raise InstallationError( error_template.format(package=req_name, reason=( "it has a 'build-system' table but not " "'build-system.requires' which is mandatory in the table" )) ) # Error out if requires is not a list of strings requires = build_system["requires"] if not _is_list_of_str(requires): raise InstallationError(error_template.format( package=req_name, reason="'build-system.requires' is not a list of strings.", )) # Each requirement must be valid as per PEP 508 for requirement in requires: try: Requirement(requirement) except InvalidRequirement: raise InstallationError( error_template.format( package=req_name, reason=( "'build-system.requires' contains an invalid " "requirement: {!r}".format(requirement) ), ) ) backend = build_system.get("build-backend") backend_path = build_system.get("backend-path", []) check = [] # type: 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, or wheel # (which is needed by the backend) in their requirements. So we # make a note to check that those requirements are 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", "wheel"] return BuildSystemDetails(requires, backend, check, backend_path)