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Diffstat (limited to 'setuptools/command/editable_wheel.py')
| -rw-r--r-- | setuptools/command/editable_wheel.py | 776 |
1 files changed, 776 insertions, 0 deletions
diff --git a/setuptools/command/editable_wheel.py b/setuptools/command/editable_wheel.py new file mode 100644 index 00000000..a44d24be --- /dev/null +++ b/setuptools/command/editable_wheel.py @@ -0,0 +1,776 @@ +""" +Create a wheel that, when installed, will make the source package 'editable' +(add it to the interpreter's path, including metadata) per PEP 660. Replaces +'setup.py develop'. + +.. note:: + One of the mechanisms briefly mentioned in PEP 660 to implement editable installs is + to create a separated directory inside ``build`` and use a .pth file to point to that + directory. In the context of this file such directory is referred as + *auxiliary build directory* or ``auxiliary_dir``. +""" + +import logging +import os +import re +import shutil +import sys +import traceback +import warnings +from contextlib import suppress +from enum import Enum +from inspect import cleandoc +from itertools import chain +from pathlib import Path +from tempfile import TemporaryDirectory +from typing import ( + TYPE_CHECKING, + Dict, + Iterable, + Iterator, + List, + Mapping, + Optional, + Tuple, + TypeVar, + Union, +) + +from setuptools import Command, SetuptoolsDeprecationWarning, errors, namespaces +from setuptools.discovery import find_package_path +from setuptools.dist import Distribution + +if TYPE_CHECKING: + from wheel.wheelfile import WheelFile # noqa + +if sys.version_info >= (3, 8): + from typing import Protocol +elif TYPE_CHECKING: + from typing_extensions import Protocol +else: + from abc import ABC as Protocol + +_Path = Union[str, Path] +_P = TypeVar("_P", bound=_Path) +_logger = logging.getLogger(__name__) + + +class _EditableMode(Enum): + """ + Possible editable installation modes: + `lenient` (new files automatically added to the package - DEFAULT); + `strict` (requires a new installation when files are added/removed); or + `compat` (attempts to emulate `python setup.py develop` - DEPRECATED). + """ + + STRICT = "strict" + LENIENT = "lenient" + COMPAT = "compat" # TODO: Remove `compat` after Dec/2022. + + @classmethod + def convert(cls, mode: Optional[str]) -> "_EditableMode": + if not mode: + return _EditableMode.LENIENT # default + + _mode = mode.upper() + if _mode not in _EditableMode.__members__: + raise errors.OptionError(f"Invalid editable mode: {mode!r}. Try: 'strict'.") + + if _mode == "COMPAT": + msg = """ + The 'compat' editable mode is transitional and will be removed + in future versions of `setuptools`. + Please adapt your code accordingly to use either the 'strict' or the + 'lenient' modes. + + For more information, please check: + https://setuptools.pypa.io/en/latest/userguide/development_mode.html + """ + warnings.warn(msg, SetuptoolsDeprecationWarning) + + return _EditableMode[_mode] + + +_STRICT_WARNING = """ +New or renamed files may not be automatically picked up without a new installation. +""" + +_LENIENT_WARNING = """ +Options like `package-data`, `include/exclude-package-data` or +`packages.find.exclude/include` may have no effect. +""" + + +class editable_wheel(Command): + """Build 'editable' wheel for development. + (This command is reserved for internal use of setuptools). + """ + + description = "create a PEP 660 'editable' wheel" + + user_options = [ + ("dist-dir=", "d", "directory to put final built distributions in"), + ("dist-info-dir=", "I", "path to a pre-build .dist-info directory"), + ("mode=", None, cleandoc(_EditableMode.__doc__ or "")), + ] + + def initialize_options(self): + self.dist_dir = None + self.dist_info_dir = None + self.project_dir = None + self.mode = None + + def finalize_options(self): + dist = self.distribution + self.project_dir = dist.src_root or os.curdir + self.package_dir = dist.package_dir or {} + self.dist_dir = Path(self.dist_dir or os.path.join(self.project_dir, "dist")) + + def run(self): + try: + self.dist_dir.mkdir(exist_ok=True) + self._ensure_dist_info() + + # Add missing dist_info files + bdist_wheel = self.reinitialize_command("bdist_wheel") + bdist_wheel.write_wheelfile(self.dist_info_dir) + + self._create_wheel_file(bdist_wheel) + except Exception as ex: + traceback.print_exc() + msg = """ + Support for editable installs via PEP 660 was recently introduced + in `setuptools`. If you are seeing this error, please report to: + + https://github.com/pypa/setuptools/issues + + Meanwhile you can try the legacy behavior by setting an + environment variable and trying to install again: + + SETUPTOOLS_ENABLE_FEATURES="legacy-editable" + """ + raise errors.InternalError(cleandoc(msg)) from ex + + def _ensure_dist_info(self): + if self.dist_info_dir is None: + dist_info = self.reinitialize_command("dist_info") + dist_info.output_dir = self.dist_dir + dist_info.finalize_options() + dist_info.run() + self.dist_info_dir = dist_info.dist_info_dir + else: + assert str(self.dist_info_dir).endswith(".dist-info") + assert Path(self.dist_info_dir, "METADATA").exists() + + def _install_namespaces(self, installation_dir, pth_prefix): + # XXX: Only required to support the deprecated namespace practice + dist = self.distribution + if not dist.namespace_packages: + return + + src_root = Path(self.project_dir, self.pakcage_dir.get("", ".")).resolve() + installer = _NamespaceInstaller(dist, installation_dir, pth_prefix, src_root) + installer.install_namespaces() + + def _find_egg_info_dir(self) -> Optional[str]: + parent_dir = Path(self.dist_info_dir).parent if self.dist_info_dir else Path() + candidates = map(str, parent_dir.glob("*.egg-info")) + return next(candidates, None) + + def _configure_build( + self, name: str, unpacked_wheel: _Path, build_lib: _Path, tmp_dir: _Path + ): + """Configure commands to behave in the following ways: + + - Build commands can write to ``build_lib`` if they really want to... + (but this folder is expected to be ignored and modules are expected to live + in the project directory...) + - Binary extensions should be built in-place (editable_mode = True) + - Data/header/script files are not part of the "editable" specification + so they are written directly to the unpacked_wheel directory. + """ + # Non-editable files (data, headers, scripts) are written directly to the + # unpacked_wheel + + dist = self.distribution + wheel = str(unpacked_wheel) + build_lib = str(build_lib) + data = str(Path(unpacked_wheel, f"{name}.data", "data")) + headers = str(Path(unpacked_wheel, f"{name}.data", "headers")) + scripts = str(Path(unpacked_wheel, f"{name}.data", "scripts")) + + # egg-info may be generated again to create a manifest (used for package data) + egg_info = dist.reinitialize_command("egg_info", reinit_subcommands=True) + egg_info.egg_base = str(tmp_dir) + egg_info.ignore_egg_info_in_manifest = True + + build = dist.reinitialize_command("build", reinit_subcommands=True) + install = dist.reinitialize_command("install", reinit_subcommands=True) + + build.build_platlib = build.build_purelib = build.build_lib = build_lib + install.install_purelib = install.install_platlib = install.install_lib = wheel + install.install_scripts = build.build_scripts = scripts + install.install_headers = headers + install.install_data = data + + install_scripts = dist.get_command_obj("install_scripts") + install_scripts.no_ep = True + + build.build_temp = str(tmp_dir) + + build_py = dist.get_command_obj("build_py") + build_py.compile = False + build_py.existing_egg_info_dir = self._find_egg_info_dir() + + self._set_editable_mode() + + build.ensure_finalized() + install.ensure_finalized() + + def _set_editable_mode(self): + """Set the ``editable_mode`` flag in the build sub-commands""" + dist = self.distribution + build = dist.get_command_obj("build") + for cmd_name in build.get_sub_commands(): + cmd = dist.get_command_obj(cmd_name) + if hasattr(cmd, "editable_mode"): + cmd.editable_mode = True + + def _collect_build_outputs(self) -> Tuple[List[str], Dict[str, str]]: + files: List[str] = [] + mapping: Dict[str, str] = {} + build = self.get_finalized_command("build") + + for cmd_name in build.get_sub_commands(): + cmd = self.get_finalized_command(cmd_name) + if hasattr(cmd, "get_outputs"): + files.extend(cmd.get_outputs() or []) + if hasattr(cmd, "get_output_mapping"): + mapping.update(cmd.get_output_mapping() or {}) + + return files, mapping + + def _run_build_commands( + self, dist_name: str, unpacked_wheel: _Path, build_lib: _Path, tmp_dir: _Path + ) -> Tuple[List[str], Dict[str, str]]: + self._configure_build(dist_name, unpacked_wheel, build_lib, tmp_dir) + self.run_command("build") + files, mapping = self._collect_build_outputs() + self._run_install("headers") + self._run_install("scripts") + self._run_install("data") + return files, mapping + + def _create_wheel_file(self, bdist_wheel): + from wheel.wheelfile import WheelFile + + dist_info = self.get_finalized_command("dist_info") + dist_name = dist_info.name + tag = "-".join(bdist_wheel.get_tag()) + build_tag = "0.editable" # According to PEP 427 needs to start with digit + archive_name = f"{dist_name}-{build_tag}-{tag}.whl" + wheel_path = Path(self.dist_dir, archive_name) + if wheel_path.exists(): + wheel_path.unlink() + + unpacked_wheel = TemporaryDirectory(suffix=archive_name) + build_lib = TemporaryDirectory(suffix=".build-lib") + build_tmp = TemporaryDirectory(suffix=".build-temp") + + with unpacked_wheel as unpacked, build_lib as lib, build_tmp as tmp: + unpacked_dist_info = Path(unpacked, Path(self.dist_info_dir).name) + shutil.copytree(self.dist_info_dir, unpacked_dist_info) + self._install_namespaces(unpacked, dist_info.name) + files, mapping = self._run_build_commands(dist_name, unpacked, lib, tmp) + strategy = self._select_strategy(dist_name, tag, lib) + with strategy, WheelFile(wheel_path, "w") as wheel_obj: + strategy(wheel_obj, files, mapping) + wheel_obj.write_files(unpacked) + + return wheel_path + + def _run_install(self, category: str): + has_category = getattr(self.distribution, f"has_{category}", None) + if has_category and has_category(): + _logger.info(f"Installing {category} as non editable") + self.run_command(f"install_{category}") + + def _select_strategy( + self, + name: str, + tag: str, + build_lib: _Path, + ) -> "EditableStrategy": + """Decides which strategy to use to implement an editable installation.""" + build_name = f"__editable__.{name}-{tag}" + project_dir = Path(self.project_dir) + mode = _EditableMode.convert(self.mode) + + if mode is _EditableMode.STRICT: + auxiliary_dir = _empty_dir(Path(self.project_dir, "build", build_name)) + return _LinkTree(self.distribution, name, auxiliary_dir, build_lib) + + packages = _find_packages(self.distribution) + has_simple_layout = _simple_layout(packages, self.package_dir, project_dir) + is_compat_mode = mode is _EditableMode.COMPAT + if set(self.package_dir) == {""} and has_simple_layout or is_compat_mode: + # src-layout(ish) is relatively safe for a simple pth file + src_dir = self.package_dir.get("", ".") + return _StaticPth(self.distribution, name, [Path(project_dir, src_dir)]) + + # Use a MetaPathFinder to avoid adding accidental top-level packages/modules + return _TopLevelFinder(self.distribution, name) + + +class EditableStrategy(Protocol): + def __call__(self, wheel: "WheelFile", files: List[str], mapping: Dict[str, str]): + ... + + def __enter__(self): + ... + + def __exit__(self, _exc_type, _exc_value, _traceback): + ... + + +class _StaticPth: + def __init__(self, dist: Distribution, name: str, path_entries: List[Path]): + self.dist = dist + self.name = name + self.path_entries = path_entries + + def __call__(self, wheel: "WheelFile", files: List[str], mapping: Dict[str, str]): + entries = "\n".join((str(p.resolve()) for p in self.path_entries)) + contents = bytes(f"{entries}\n", "utf-8") + wheel.writestr(f"__editable__.{self.name}.pth", contents) + + def __enter__(self): + msg = f""" + Editable install will be performed using .pth file to extend `sys.path` with: + {self.path_entries!r} + """ + _logger.warning(msg + _LENIENT_WARNING) + return self + + def __exit__(self, _exc_type, _exc_value, _traceback): + ... + + +class _LinkTree(_StaticPth): + """ + Creates a ``.pth`` file that points to a link tree in the ``auxiliary_dir``. + + This strategy will only link files (not dirs), so it can be implemented in + any OS, even if that means using hardlinks instead of symlinks. + + By collocating ``auxiliary_dir`` and the original source code, limitations + with hardlinks should be avoided. + """ + def __init__( + self, dist: Distribution, + name: str, + auxiliary_dir: _Path, + build_lib: _Path, + ): + self.auxiliary_dir = Path(auxiliary_dir) + self.build_lib = Path(build_lib).resolve() + self._file = dist.get_command_obj("build_py").copy_file + super().__init__(dist, name, [self.auxiliary_dir]) + + def __call__(self, wheel: "WheelFile", files: List[str], mapping: Dict[str, str]): + self._create_links(files, mapping) + super().__call__(wheel, files, mapping) + + def _normalize_output(self, file: str) -> Optional[str]: + # Files relative to build_lib will be normalized to None + with suppress(ValueError): + path = Path(file).resolve().relative_to(self.build_lib) + return str(path).replace(os.sep, '/') + return None + + def _create_file(self, relative_output: str, src_file: str, link=None): + dest = self.auxiliary_dir / relative_output + if not dest.parent.is_dir(): + dest.parent.mkdir(parents=True) + self._file(src_file, dest, link=link) + + def _create_links(self, outputs, output_mapping): + self.auxiliary_dir.mkdir(parents=True, exist_ok=True) + link_type = "sym" if _can_symlink_files(self.auxiliary_dir) else "hard" + mappings = { + self._normalize_output(k): v + for k, v in output_mapping.items() + } + mappings.pop(None, None) # remove files that are not relative to build_lib + + for output in outputs: + relative = self._normalize_output(output) + if relative and relative not in mappings: + self._create_file(relative, output) + + for relative, src in mappings.items(): + self._create_file(relative, src, link=link_type) + + def __enter__(self): + msg = "Strict editable install will be performed using a link tree.\n" + _logger.warning(msg + _STRICT_WARNING) + return self + + def __exit__(self, _exc_type, _exc_value, _traceback): + msg = f"""\n + Strict editable installation performed using the auxiliary directory: + {self.auxiliary_dir} + + Please be careful to not remove this directory, otherwise you might not be able + to import/use your package. + """ + warnings.warn(msg, InformationOnly) + + +class _TopLevelFinder: + def __init__(self, dist: Distribution, name: str): + self.dist = dist + self.name = name + + def __call__(self, wheel: "WheelFile", files: List[str], mapping: Dict[str, str]): + src_root = self.dist.src_root or os.curdir + top_level = chain(_find_packages(self.dist), _find_top_level_modules(self.dist)) + package_dir = self.dist.package_dir or {} + roots = _find_package_roots(top_level, package_dir, src_root) + + namespaces_: Dict[str, List[str]] = dict(chain( + _find_namespaces(self.dist.packages, roots), + ((ns, []) for ns in _find_virtual_namespaces(roots)), + )) + + name = f"__editable__.{self.name}.finder" + finder = _make_identifier(name) + content = bytes(_finder_template(name, roots, namespaces_), "utf-8") + wheel.writestr(f"{finder}.py", content) + + content = bytes(f"import {finder}; {finder}.install()", "utf-8") + wheel.writestr(f"__editable__.{self.name}.pth", content) + + def __enter__(self): + msg = "Editable install will be performed using a meta path finder.\n" + _logger.warning(msg + _LENIENT_WARNING) + return self + + def __exit__(self, _exc_type, _exc_value, _traceback): + ... + + +def _can_symlink_files(base_dir: Path) -> bool: + with TemporaryDirectory(dir=str(base_dir.resolve())) as tmp: + path1, path2 = Path(tmp, "file1.txt"), Path(tmp, "file2.txt") + path1.write_text("file1", encoding="utf-8") + with suppress(AttributeError, NotImplementedError, OSError): + os.symlink(path1, path2) + if path2.is_symlink() and path2.read_text(encoding="utf-8") == "file1": + return True + + try: + os.link(path1, path2) # Ensure hard links can be created + except Exception as ex: + msg = ( + "File system does not seem to support either symlinks or hard links. " + "Strict editable installs require one of them to be supported." + ) + raise LinksNotSupported(msg) from ex + return False + + +def _simple_layout( + packages: Iterable[str], package_dir: Dict[str, str], project_dir: Path +) -> bool: + """Return ``True`` if: + - all packages are contained by the same parent directory, **and** + - all packages become importable if the parent directory is added to ``sys.path``. + + >>> _simple_layout(['a'], {"": "src"}, "/tmp/myproj") + True + >>> _simple_layout(['a', 'a.b'], {"": "src"}, "/tmp/myproj") + True + >>> _simple_layout(['a', 'a.b'], {}, "/tmp/myproj") + True + >>> _simple_layout(['a', 'a.a1', 'a.a1.a2', 'b'], {"": "src"}, "/tmp/myproj") + True + >>> _simple_layout(['a', 'a.a1', 'a.a1.a2', 'b'], {"a": "a", "b": "b"}, ".") + True + >>> _simple_layout(['a', 'a.a1', 'a.a1.a2', 'b'], {"a": "_a", "b": "_b"}, ".") + False + >>> _simple_layout(['a', 'a.a1', 'a.a1.a2', 'b'], {"a": "_a"}, "/tmp/myproj") + False + >>> _simple_layout(['a', 'a.a1', 'a.a1.a2', 'b'], {"a.a1.a2": "_a2"}, ".") + False + >>> _simple_layout(['a', 'a.b'], {"": "src", "a.b": "_ab"}, "/tmp/myproj") + False + """ + layout = { + pkg: find_package_path(pkg, package_dir, project_dir) + for pkg in packages + } + if not layout: + return False + parent = os.path.commonpath([_parent_path(k, v) for k, v in layout.items()]) + return all( + _normalize_path(Path(parent, *key.split('.'))) == _normalize_path(value) + for key, value in layout.items() + ) + + +def _parent_path(pkg, pkg_path): + """Infer the parent path containing a package, that if added to ``sys.path`` would + allow importing that package. + When ``pkg`` is directly mapped into a directory with a different name, return its + own path. + >>> _parent_path("a", "src/a") + 'src' + >>> _parent_path("b", "src/c") + 'src/c' + """ + parent = pkg_path[:-len(pkg)] if pkg_path.endswith(pkg) else pkg_path + return parent.rstrip("/" + os.sep) + + +def _find_packages(dist: Distribution) -> Iterator[str]: + yield from iter(dist.packages or []) + + py_modules = dist.py_modules or [] + nested_modules = [mod for mod in py_modules if "." in mod] + if dist.ext_package: + yield dist.ext_package + else: + ext_modules = dist.ext_modules or [] + nested_modules += [x.name for x in ext_modules if "." in x.name] + + for module in nested_modules: + package, _, _ = module.rpartition(".") + yield package + + +def _find_top_level_modules(dist: Distribution) -> Iterator[str]: + py_modules = dist.py_modules or [] + yield from (mod for mod in py_modules if "." not in mod) + + if not dist.ext_package: + ext_modules = dist.ext_modules or [] + yield from (x.name for x in ext_modules if "." not in x.name) + + +def _find_package_roots( + packages: Iterable[str], + package_dir: Mapping[str, str], + src_root: _Path, +) -> Dict[str, str]: + pkg_roots: Dict[str, str] = { + pkg: _absolute_root(find_package_path(pkg, package_dir, src_root)) + for pkg in sorted(packages) + } + + return _remove_nested(pkg_roots) + + +def _absolute_root(path: _Path) -> str: + """Works for packages and top-level modules""" + path_ = Path(path) + parent = path_.parent + + if path_.exists(): + return str(path_.resolve()) + else: + return str(parent.resolve() / path_.name) + + +def _find_virtual_namespaces(pkg_roots: Dict[str, str]) -> Iterator[str]: + """By carefully designing ``package_dir``, it is possible to implement the logical + structure of PEP 420 in a package without the corresponding directories. + This function will try to find this kind of namespaces. + """ + for pkg in pkg_roots: + if "." not in pkg: + continue + parts = pkg.split(".") + for i in range(len(parts) - 1, 0, -1): + partial_name = ".".join(parts[:i]) + path = Path(find_package_path(partial_name, pkg_roots, "")) + if not path.exists(): + yield partial_name + + +def _find_namespaces( + packages: List[str], pkg_roots: Dict[str, str] +) -> Iterator[Tuple[str, List[str]]]: + for pkg in packages: + path = find_package_path(pkg, pkg_roots, "") + if Path(path).exists() and not Path(path, "__init__.py").exists(): + yield (pkg, [path]) + + +def _remove_nested(pkg_roots: Dict[str, str]) -> Dict[str, str]: + output = dict(pkg_roots.copy()) + + for pkg, path in reversed(list(pkg_roots.items())): + if any( + pkg != other and _is_nested(pkg, path, other, other_path) + for other, other_path in pkg_roots.items() + ): + output.pop(pkg) + + return output + + +def _is_nested(pkg: str, pkg_path: str, parent: str, parent_path: str) -> bool: + """ + Return ``True`` if ``pkg`` is nested inside ``parent`` both logically and in the + file system. + >>> _is_nested("a.b", "path/a/b", "a", "path/a") + True + >>> _is_nested("a.b", "path/a/b", "a", "otherpath/a") + False + >>> _is_nested("a.b", "path/a/b", "c", "path/c") + False + """ + norm_pkg_path = _normalize_path(pkg_path) + rest = pkg.replace(parent, "").strip(".").split(".") + return ( + pkg.startswith(parent) + and norm_pkg_path == _normalize_path(Path(parent_path, *rest)) + ) + + +def _normalize_path(filename: _Path) -> str: + """Normalize a file/dir name for comparison purposes""" + # See pkg_resources.normalize_path + file = os.path.abspath(filename) if sys.platform == 'cygwin' else filename + return os.path.normcase(os.path.realpath(os.path.normpath(file))) + + +def _empty_dir(dir_: _P) -> _P: + """Create a directory ensured to be empty. Existing files may be removed.""" + shutil.rmtree(dir_, ignore_errors=True) + os.makedirs(dir_) + return dir_ + + +def _make_identifier(name: str) -> str: + """Make a string safe to be used as Python identifier. + >>> _make_identifier("12abc") + '_12abc' + >>> _make_identifier("__editable__.myns.pkg-78.9.3_local") + '__editable___myns_pkg_78_9_3_local' + """ + safe = re.sub(r'\W|^(?=\d)', '_', name) + assert safe.isidentifier() + return safe + + +class _NamespaceInstaller(namespaces.Installer): + def __init__(self, distribution, installation_dir, editable_name, src_root): + self.distribution = distribution + self.src_root = src_root + self.installation_dir = installation_dir + self.editable_name = editable_name + self.outputs = [] + + def _get_target(self): + """Installation target.""" + return os.path.join(self.installation_dir, self.editable_name) + + def _get_root(self): + """Where the modules/packages should be loaded from.""" + return repr(str(self.src_root)) + + +_FINDER_TEMPLATE = """\ +import sys +from importlib.machinery import ModuleSpec +from importlib.machinery import all_suffixes as module_suffixes +from importlib.util import spec_from_file_location +from itertools import chain +from pathlib import Path + +MAPPING = {mapping!r} +NAMESPACES = {namespaces!r} +PATH_PLACEHOLDER = {name!r} + ".__path_hook__" + + +class _EditableFinder: # MetaPathFinder + @classmethod + def find_spec(cls, fullname, path=None, target=None): + for pkg, pkg_path in reversed(list(MAPPING.items())): + if fullname.startswith(pkg): + rest = fullname.replace(pkg, "").strip(".").split(".") + return cls._find_spec(fullname, Path(pkg_path, *rest)) + + return None + + @classmethod + def _find_spec(cls, fullname, candidate_path): + init = candidate_path / "__init__.py" + candidates = (candidate_path.with_suffix(x) for x in module_suffixes()) + for candidate in chain([init], candidates): + if candidate.exists(): + return spec_from_file_location(fullname, candidate) + + +class _EditableNamespaceFinder: # PathEntryFinder + @classmethod + def _path_hook(cls, path): + if path == PATH_PLACEHOLDER: + return cls + raise ImportError + + @classmethod + def _paths(cls, fullname): + # Ensure __path__ is not empty for the spec to be considered a namespace. + return NAMESPACES[fullname] or MAPPING.get(fullname) or [PATH_PLACEHOLDER] + + @classmethod + def find_spec(cls, fullname, target=None): + if fullname in NAMESPACES: + spec = ModuleSpec(fullname, None, is_package=True) + spec.submodule_search_locations = cls._paths(fullname) + return spec + return None + + @classmethod + def find_module(cls, fullname): + return None + + +def install(): + if not any(finder == _EditableFinder for finder in sys.meta_path): + sys.meta_path.append(_EditableFinder) + + if not NAMESPACES: + return + + if not any(hook == _EditableNamespaceFinder._path_hook for hook in sys.path_hooks): + # PathEntryFinder is needed to create NamespaceSpec without private APIS + sys.path_hooks.append(_EditableNamespaceFinder._path_hook) + if PATH_PLACEHOLDER not in sys.path: + sys.path.append(PATH_PLACEHOLDER) # Used just to trigger the path hook +""" + + +def _finder_template( + name: str, mapping: Mapping[str, str], namespaces: Dict[str, List[str]] +) -> str: + """Create a string containing the code for the``MetaPathFinder`` and + ``PathEntryFinder``. + """ + mapping = dict(sorted(mapping.items(), key=lambda p: p[0])) + return _FINDER_TEMPLATE.format(name=name, mapping=mapping, namespaces=namespaces) + + +class InformationOnly(UserWarning): + """Currently there is no clear way of displaying messages to the users + that use the setuptools backend directly via ``pip``. + The only thing that might work is a warning, although it is not the + most appropriate tool for the job... + """ + + +class LinksNotSupported(errors.FileError): + """File system does not seem to support either symlinks or hard links.""" |