from __future__ import annotations import contextlib import functools import operator import os import shutil import subprocess import sys import tempfile import urllib.request import warnings from typing import Iterator if sys.version_info < (3, 12): from setuptools.extern.backports import tarfile else: import tarfile @contextlib.contextmanager def pushd(dir: str | os.PathLike) -> Iterator[str | os.PathLike]: """ >>> tmp_path = getfixture('tmp_path') >>> with pushd(tmp_path): ... assert os.getcwd() == os.fspath(tmp_path) >>> assert os.getcwd() != os.fspath(tmp_path) """ orig = os.getcwd() os.chdir(dir) try: yield dir finally: os.chdir(orig) @contextlib.contextmanager def tarball( url, target_dir: str | os.PathLike | None = None ) -> Iterator[str | os.PathLike]: """ Get a tarball, extract it, yield, then clean up. >>> import urllib.request >>> url = getfixture('tarfile_served') >>> target = getfixture('tmp_path') / 'out' >>> tb = tarball(url, target_dir=target) >>> import pathlib >>> with tb as extracted: ... contents = pathlib.Path(extracted, 'contents.txt').read_text(encoding='utf-8') >>> assert not os.path.exists(extracted) """ if target_dir is None: target_dir = os.path.basename(url).replace('.tar.gz', '').replace('.tgz', '') # In the tar command, use --strip-components=1 to strip the first path and # then # use -C to cause the files to be extracted to {target_dir}. This ensures # that we always know where the files were extracted. os.mkdir(target_dir) try: req = urllib.request.urlopen(url) with tarfile.open(fileobj=req, mode='r|*') as tf: tf.extractall(path=target_dir, filter=strip_first_component) yield target_dir finally: shutil.rmtree(target_dir) def strip_first_component( member: tarfile.TarInfo, path, ) -> tarfile.TarInfo: _, member.name = member.name.split('/', 1) return member def _compose(*cmgrs): """ Compose any number of dependent context managers into a single one. The last, innermost context manager may take arbitrary arguments, but each successive context manager should accept the result from the previous as a single parameter. Like :func:`jaraco.functools.compose`, behavior works from right to left, so the context manager should be indicated from outermost to innermost. Example, to create a context manager to change to a temporary directory: >>> temp_dir_as_cwd = _compose(pushd, temp_dir) >>> with temp_dir_as_cwd() as dir: ... assert os.path.samefile(os.getcwd(), dir) """ def compose_two(inner, outer): def composed(*args, **kwargs): with inner(*args, **kwargs) as saved, outer(saved) as res: yield res return contextlib.contextmanager(composed) return functools.reduce(compose_two, reversed(cmgrs)) tarball_cwd = _compose(pushd, tarball) @contextlib.contextmanager def tarball_context(*args, **kwargs): warnings.warn( "tarball_context is deprecated. Use tarball or tarball_cwd instead.", DeprecationWarning, stacklevel=2, ) pushd_ctx = kwargs.pop('pushd', pushd) with tarball(*args, **kwargs) as tball, pushd_ctx(tball) as dir: yield dir def infer_compression(url): """ Given a URL or filename, infer the compression code for tar. >>> infer_compression('http://foo/bar.tar.gz') 'z' >>> infer_compression('http://foo/bar.tgz') 'z' >>> infer_compression('file.bz') 'j' >>> infer_compression('file.xz') 'J' """ warnings.warn( "infer_compression is deprecated with no replacement", DeprecationWarning, stacklevel=2, ) # cheat and just assume it's the last two characters compression_indicator = url[-2:] mapping = dict(gz='z', bz='j', xz='J') # Assume 'z' (gzip) if no match return mapping.get(compression_indicator, 'z') @contextlib.contextmanager def temp_dir(remover=shutil.rmtree): """ Create a temporary directory context. Pass a custom remover to override the removal behavior. >>> import pathlib >>> with temp_dir() as the_dir: ... assert os.path.isdir(the_dir) ... _ = pathlib.Path(the_dir).joinpath('somefile').write_text('contents', encoding='utf-8') >>> assert not os.path.exists(the_dir) """ temp_dir = tempfile.mkdtemp() try: yield temp_dir finally: remover(temp_dir) @contextlib.contextmanager def repo_context(url, branch=None, quiet=True, dest_ctx=temp_dir): """ Check out the repo indicated by url. If dest_ctx is supplied, it should be a context manager to yield the target directory for the check out. """ exe = 'git' if 'git' in url else 'hg' with dest_ctx() as repo_dir: cmd = [exe, 'clone', url, repo_dir] if branch: cmd.extend(['--branch', branch]) devnull = open(os.path.devnull, 'w') stdout = devnull if quiet else None subprocess.check_call(cmd, stdout=stdout) yield repo_dir def null(): """ A null context suitable to stand in for a meaningful context. >>> with null() as value: ... assert value is None This context is most useful when dealing with two or more code branches but only some need a context. Wrap the others in a null context to provide symmetry across all options. """ warnings.warn( "null is deprecated. Use contextlib.nullcontext", DeprecationWarning, stacklevel=2, ) return contextlib.nullcontext() class ExceptionTrap: """ A context manager that will catch certain exceptions and provide an indication they occurred. >>> with ExceptionTrap() as trap: ... raise Exception() >>> bool(trap) True >>> with ExceptionTrap() as trap: ... pass >>> bool(trap) False >>> with ExceptionTrap(ValueError) as trap: ... raise ValueError("1 + 1 is not 3") >>> bool(trap) True >>> trap.value ValueError('1 + 1 is not 3') >>> trap.tb <traceback object at ...> >>> with ExceptionTrap(ValueError) as trap: ... raise Exception() Traceback (most recent call last): ... Exception >>> bool(trap) False """ exc_info = None, None, None def __init__(self, exceptions=(Exception,)): self.exceptions = exceptions def __enter__(self): return self @property def type(self): return self.exc_info[0] @property def value(self): return self.exc_info[1] @property def tb(self): return self.exc_info[2] def __exit__(self, *exc_info): type = exc_info[0] matches = type and issubclass(type, self.exceptions) if matches: self.exc_info = exc_info return matches def __bool__(self): return bool(self.type) def raises(self, func, *, _test=bool): """ Wrap func and replace the result with the truth value of the trap (True if an exception occurred). First, give the decorator an alias to support Python 3.8 Syntax. >>> raises = ExceptionTrap(ValueError).raises Now decorate a function that always fails. >>> @raises ... def fail(): ... raise ValueError('failed') >>> fail() True """ @functools.wraps(func) def wrapper(*args, **kwargs): with ExceptionTrap(self.exceptions) as trap: func(*args, **kwargs) return _test(trap) return wrapper def passes(self, func): """ Wrap func and replace the result with the truth value of the trap (True if no exception). First, give the decorator an alias to support Python 3.8 Syntax. >>> passes = ExceptionTrap(ValueError).passes Now decorate a function that always fails. >>> @passes ... def fail(): ... raise ValueError('failed') >>> fail() False """ return self.raises(func, _test=operator.not_) class suppress(contextlib.suppress, contextlib.ContextDecorator): """ A version of contextlib.suppress with decorator support. >>> @suppress(KeyError) ... def key_error(): ... {}[''] >>> key_error() """ class on_interrupt(contextlib.ContextDecorator): """ Replace a KeyboardInterrupt with SystemExit(1) >>> def do_interrupt(): ... raise KeyboardInterrupt() >>> on_interrupt('error')(do_interrupt)() Traceback (most recent call last): ... SystemExit: 1 >>> on_interrupt('error', code=255)(do_interrupt)() Traceback (most recent call last): ... SystemExit: 255 >>> on_interrupt('suppress')(do_interrupt)() >>> with __import__('pytest').raises(KeyboardInterrupt): ... on_interrupt('ignore')(do_interrupt)() """ def __init__(self, action='error', /, code=1): self.action = action self.code = code def __enter__(self): return self def __exit__(self, exctype, excinst, exctb): if exctype is not KeyboardInterrupt or self.action == 'ignore': return elif self.action == 'error': raise SystemExit(self.code) from excinst return self.action == 'suppress'