3 from collections
import namedtuple
4 from typing
import Any
, List
, Optional
6 from pip
._vendor
import tomli
7 from pip
._vendor
.packaging
.requirements
import InvalidRequirement
, Requirement
9 from pip
._internal
.exceptions
import (
11 InvalidPyProjectBuildRequires
,
12 MissingPyProjectBuildRequires
,
16 def _is_list_of_str(obj
: Any
) -> bool:
17 return isinstance(obj
, list) and all(isinstance(item
, str) for item
in obj
)
20 def make_pyproject_path(unpacked_source_directory
: str) -> str:
21 return os
.path
.join(unpacked_source_directory
, "pyproject.toml")
24 BuildSystemDetails
= namedtuple(
25 "BuildSystemDetails", ["requires", "backend", "check", "backend_path"]
29 def load_pyproject_toml(
30 use_pep517
: Optional
[bool], pyproject_toml
: str, setup_py
: str, req_name
: str
31 ) -> Optional
[BuildSystemDetails
]:
32 """Load the pyproject.toml file.
35 use_pep517 - Has the user requested PEP 517 processing? None
36 means the user hasn't explicitly specified.
37 pyproject_toml - Location of the project's pyproject.toml file
38 setup_py - Location of the project's setup.py file
39 req_name - The name of the requirement we're processing (for
43 None if we should use the legacy code path, otherwise a tuple
45 requirements from pyproject.toml,
46 name of PEP 517 backend,
47 requirements we should check are installed after setting
48 up the build environment
49 directory paths to import the backend from (backend-path),
50 relative to the project root.
53 has_pyproject
= os
.path
.isfile(pyproject_toml
)
54 has_setup
= os
.path
.isfile(setup_py
)
56 if not has_pyproject
and not has_setup
:
57 raise InstallationError(
58 f
"{req_name} does not appear to be a Python project: "
59 f
"neither 'setup.py' nor 'pyproject.toml' found."
63 with
open(pyproject_toml
, encoding
="utf-8") as f
:
64 pp_toml
= tomli
.loads(f
.read())
65 build_system
= pp_toml
.get("build-system")
69 # The following cases must use PEP 517
70 # We check for use_pep517 being non-None and falsey because that means
71 # the user explicitly requested --no-use-pep517. The value 0 as
72 # opposed to False can occur when the value is provided via an
73 # environment variable or config file option (due to the quirk of
74 # strtobool() returning an integer in pip's configuration code).
75 if has_pyproject
and not has_setup
:
76 if use_pep517
is not None and not use_pep517
:
77 raise InstallationError(
78 "Disabling PEP 517 processing is invalid: "
79 "project does not have a setup.py"
82 elif build_system
and "build-backend" in build_system
:
83 if use_pep517
is not None and not use_pep517
:
84 raise InstallationError(
85 "Disabling PEP 517 processing is invalid: "
86 "project specifies a build backend of {} "
87 "in pyproject.toml".format(build_system
["build-backend"])
91 # If we haven't worked out whether to use PEP 517 yet,
92 # and the user hasn't explicitly stated a preference,
93 # we do so if the project has a pyproject.toml file
94 # or if we cannot import setuptools.
96 # We fallback to PEP 517 when without setuptools,
97 # so setuptools can be installed as a default build backend.
99 # https://discuss.python.org/t/pip-without-setuptools-could-the-experience-be-improved/11810/9
100 elif use_pep517
is None:
101 use_pep517
= has_pyproject
or not importlib
.util
.find_spec("setuptools")
103 # At this point, we know whether we're going to use PEP 517.
104 assert use_pep517
is not None
106 # If we're using the legacy code path, there is nothing further
111 if build_system
is None:
112 # Either the user has a pyproject.toml with no build-system
113 # section, or the user has no pyproject.toml, but has opted in
114 # explicitly via --use-pep517.
115 # In the absence of any explicit backend specification, we
116 # assume the setuptools backend that most closely emulates the
117 # traditional direct setup.py execution, and require wheel and
118 # a version of setuptools that supports that backend.
121 "requires": ["setuptools>=40.8.0", "wheel"],
122 "build-backend": "setuptools.build_meta:__legacy__",
125 # If we're using PEP 517, we have build system information (either
126 # from pyproject.toml, or defaulted by the code above).
127 # Note that at this point, we do not know if the user has actually
128 # specified a backend, though.
129 assert build_system
is not None
131 # Ensure that the build-system section in pyproject.toml conforms
134 # Specifying the build-system table but not the requires key is invalid
135 if "requires" not in build_system
:
136 raise MissingPyProjectBuildRequires(package
=req_name
)
138 # Error out if requires is not a list of strings
139 requires
= build_system
["requires"]
140 if not _is_list_of_str(requires
):
141 raise InvalidPyProjectBuildRequires(
143 reason
="It is not a list of strings.",
146 # Each requirement must be valid as per PEP 508
147 for requirement
in requires
:
149 Requirement(requirement
)
150 except InvalidRequirement
as error
:
151 raise InvalidPyProjectBuildRequires(
153 reason
=f
"It contains an invalid requirement: {requirement!r}",
156 backend
= build_system
.get("build-backend")
157 backend_path
= build_system
.get("backend-path", [])
158 check
: List
[str] = []
160 # If the user didn't specify a backend, we assume they want to use
161 # the setuptools backend. But we can't be sure they have included
162 # a version of setuptools which supplies the backend. So we
163 # make a note to check that this requirement is present once
164 # we have set up the environment.
165 # This is quite a lot of work to check for a very specific case. But
166 # the problem is, that case is potentially quite common - projects that
167 # adopted PEP 518 early for the ability to specify requirements to
168 # execute setup.py, but never considered needing to mention the build
169 # tools themselves. The original PEP 518 code had a similar check (but
170 # implemented in a different way).
171 backend
= "setuptools.build_meta:__legacy__"
172 check
= ["setuptools>=40.8.0"]
174 return BuildSystemDetails(requires
, backend
, check
, backend_path
)