| 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, 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) |
