Voice et bot modif

venv/lib/python3.12/site-packages/pip/_internal/pyproject.py

@@ -1,18 +1,16 @@
-from __future__ import annotations
-
+import importlib.util
 import os
 from collections import namedtuple
-from typing import Any
+from typing import Any, List, Optional
 
-from pip._vendor.packaging.requirements import InvalidRequirement
+from pip._vendor import tomli
+from pip._vendor.packaging.requirements import InvalidRequirement, Requirement
 
 from pip._internal.exceptions import (
     InstallationError,
     InvalidPyProjectBuildRequires,
     MissingPyProjectBuildRequires,
 )
-from pip._internal.utils.compat import tomllib
-from pip._internal.utils.packaging import get_requirement
 
 
 def _is_list_of_str(obj: Any) -> bool:
@@ -29,11 +27,13 @@ BuildSystemDetails = namedtuple(
 
 
 def load_pyproject_toml(
-    pyproject_toml: str, setup_py: str, req_name: str
-) -> BuildSystemDetails:
+    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
@@ -61,12 +61,62 @@ def load_pyproject_toml(
 
     if has_pyproject:
         with open(pyproject_toml, encoding="utf-8") as f:
-            pp_toml = tomllib.loads(f.read())
+            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 or wheels.
+
+    # We fallback to PEP 517 when without setuptools or without the wheel package,
+    # 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
+    # https://github.com/pypa/pip/issues/8559
+    elif use_pep517 is None:
+        use_pep517 = (
+            has_pyproject
+            or not importlib.util.find_spec("setuptools")
+            or not importlib.util.find_spec("wheel")
+        )
+
+    # 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
@@ -77,6 +127,12 @@ def load_pyproject_toml(
             "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.
 
@@ -95,7 +151,7 @@ def load_pyproject_toml(
     # Each requirement must be valid as per PEP 508
     for requirement in requires:
         try:
-            get_requirement(requirement)
+            Requirement(requirement)
         except InvalidRequirement as error:
             raise InvalidPyProjectBuildRequires(
                 package=req_name,
@@ -104,7 +160,7 @@ def load_pyproject_toml(
 
     backend = build_system.get("build-backend")
     backend_path = build_system.get("backend-path", [])
-    check: list[str] = []
+    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