def get_pep_518_info(self):
"""Get a list of the packages required to build the project, if any,
and a flag indicating whether pyproject.toml is present, indicating
that the build should be isolated.
Build requirements can be specified in a pyproject.toml, as described
in PEP 518. If this file exists but doesn't specify build
requirements, pip will default to installing setuptools and wheel.
"""
if os.path.isfile(self.pyproject_toml):
with open(self.pyproject_toml) as f:
pp_toml = pytoml.load(f)
build_sys = pp_toml.get('build-system', {})
return (build_sys.get('requires', ['setuptools', 'wheel']), True)
return (['setuptools', 'wheel'], False)
def build(source_dir, dist, dest=None):
pyproject = os.path.join(source_dir, 'pyproject.toml')
dest = os.path.join(source_dir, dest or 'dist')
mkdir_p(dest)
with open(pyproject) as f:
pyproject_data = pytoml.load(f)
# Ensure the mandatory data can be loaded
buildsys = pyproject_data['build-system']
requires = buildsys['requires']
backend = buildsys['build-backend']
hooks = Pep517HookCaller(source_dir, backend)
with BuildEnvironment() as env:
env.pip_install(requires)
_do_build(hooks, env, dist, dest)
def get_pep_518_info(self):
"""Get PEP 518 build-time requirements.
Returns the list of the packages required to build the project,
specified as per PEP 518 within the package. If `pyproject.toml` is not
present, returns None to signify not using the same.
"""
# If pyproject.toml does not exist, don't do anything.
if not os.path.isfile(self.pyproject_toml):
return None
error_template = (
"{package} has a pyproject.toml file that does not comply "
"with PEP 518: {reason}")
with io.open(self.pyproject_toml, encoding="utf-8") as f:
pp_toml = pytoml.load(f)
# If there is no build-system table, just use setuptools and wheel.
if "build-system" not in pp_toml:
return ["setuptools", "wheel"]
# Specifying the build-system table but not the requires key is invalid
build_system = pp_toml["build-system"]
if "requires" not in build_system:
raise InstallationError(
error_template.format(
package=self,
reason=
("it has a 'build-system' table but not "
"'build-system.requires' which is mandatory in the table"
)))
# Error out if it's not a list of strings
requires = build_system["requires"]
if not _is_list_of_str(requires):
raise InstallationError(
error_template.format(
package=self,
reason="'build-system.requires' is not a list of strings.",
))
return requires
def load_pyproject_toml(
use_pep517, # type: Optional[bool]
pyproject_toml, # type: str
setup_py, # type: str
req_name # type: str
):
# type: (...) -> Optional[Tuple[List[str], str, List[str]]]
"""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
)
"""
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 = pytoml.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.",
))
backend = build_system.get("build-backend")
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 (requires, backend, check)
def _load_pyproject(source_dir):
with open(os.path.join(source_dir, 'pyproject.toml')) as f:
pyproject_data = pytoml.load(f)
buildsys = pyproject_data['build-system']
return buildsys['requires'], buildsys['build-backend']