481 lines
17 KiB
Python
481 lines
17 KiB
Python
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"""
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Environments are a way to activate different Python versions or Virtualenvs for
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static analysis. The Python binary in that environment is going to be executed.
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"""
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import os
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import sys
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import hashlib
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import filecmp
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from collections import namedtuple
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from jedi._compatibility import highest_pickle_protocol, which
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from jedi.cache import memoize_method, time_cache
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from jedi.inference.compiled.subprocess import CompiledSubprocess, \
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InferenceStateSameProcess, InferenceStateSubprocess
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import parso
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_VersionInfo = namedtuple('VersionInfo', 'major minor micro')
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_SUPPORTED_PYTHONS = ['3.8', '3.7', '3.6', '3.5', '2.7']
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_SAFE_PATHS = ['/usr/bin', '/usr/local/bin']
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_CONDA_VAR = 'CONDA_PREFIX'
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_CURRENT_VERSION = '%s.%s' % (sys.version_info.major, sys.version_info.minor)
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class InvalidPythonEnvironment(Exception):
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"""
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If you see this exception, the Python executable or Virtualenv you have
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been trying to use is probably not a correct Python version.
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"""
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class _BaseEnvironment(object):
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@memoize_method
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def get_grammar(self):
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version_string = '%s.%s' % (self.version_info.major, self.version_info.minor)
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return parso.load_grammar(version=version_string)
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@property
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def _sha256(self):
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try:
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return self._hash
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except AttributeError:
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self._hash = _calculate_sha256_for_file(self.executable)
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return self._hash
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def _get_info():
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return (
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sys.executable,
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sys.prefix,
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sys.version_info[:3],
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)
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class Environment(_BaseEnvironment):
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"""
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This class is supposed to be created by internal Jedi architecture. You
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should not create it directly. Please use create_environment or the other
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functions instead. It is then returned by that function.
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"""
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_subprocess = None
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def __init__(self, executable):
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self._start_executable = executable
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# Initialize the environment
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self._get_subprocess()
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def _get_subprocess(self):
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if self._subprocess is not None and not self._subprocess.is_crashed:
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return self._subprocess
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try:
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self._subprocess = CompiledSubprocess(self._start_executable)
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info = self._subprocess._send(None, _get_info)
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except Exception as exc:
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raise InvalidPythonEnvironment(
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"Could not get version information for %r: %r" % (
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self._start_executable,
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exc))
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# Since it could change and might not be the same(?) as the one given,
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# set it here.
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self.executable = info[0]
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"""
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The Python executable, matches ``sys.executable``.
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"""
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self.path = info[1]
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"""
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The path to an environment, matches ``sys.prefix``.
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"""
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self.version_info = _VersionInfo(*info[2])
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"""
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Like :data:`sys.version_info`: a tuple to show the current
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Environment's Python version.
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"""
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# py2 sends bytes via pickle apparently?!
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if self.version_info.major == 2:
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self.executable = self.executable.decode()
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self.path = self.path.decode()
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# Adjust pickle protocol according to host and client version.
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self._subprocess._pickle_protocol = highest_pickle_protocol([
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sys.version_info, self.version_info])
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return self._subprocess
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def __repr__(self):
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version = '.'.join(str(i) for i in self.version_info)
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return '<%s: %s in %s>' % (self.__class__.__name__, version, self.path)
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def get_inference_state_subprocess(self, inference_state):
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return InferenceStateSubprocess(inference_state, self._get_subprocess())
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@memoize_method
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def get_sys_path(self):
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"""
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The sys path for this environment. Does not include potential
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modifications from e.g. appending to :data:`sys.path`.
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:returns: list of str
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"""
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# It's pretty much impossible to generate the sys path without actually
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# executing Python. The sys path (when starting with -S) itself depends
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# on how the Python version was compiled (ENV variables).
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# If you omit -S when starting Python (normal case), additionally
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# site.py gets executed.
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return self._get_subprocess().get_sys_path()
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class _SameEnvironmentMixin(object):
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def __init__(self):
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self._start_executable = self.executable = sys.executable
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self.path = sys.prefix
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self.version_info = _VersionInfo(*sys.version_info[:3])
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class SameEnvironment(_SameEnvironmentMixin, Environment):
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pass
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class InterpreterEnvironment(_SameEnvironmentMixin, _BaseEnvironment):
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def get_inference_state_subprocess(self, inference_state):
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return InferenceStateSameProcess(inference_state)
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def get_sys_path(self):
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return sys.path
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def _get_virtual_env_from_var(env_var='VIRTUAL_ENV'):
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"""Get virtualenv environment from VIRTUAL_ENV environment variable.
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It uses `safe=False` with ``create_environment``, because the environment
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variable is considered to be safe / controlled by the user solely.
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"""
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var = os.environ.get(env_var)
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if var:
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# Under macOS in some cases - notably when using Pipenv - the
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# sys.prefix of the virtualenv is /path/to/env/bin/.. instead of
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# /path/to/env so we need to fully resolve the paths in order to
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# compare them.
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if os.path.realpath(var) == os.path.realpath(sys.prefix):
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return _try_get_same_env()
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try:
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return create_environment(var, safe=False)
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except InvalidPythonEnvironment:
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pass
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def _calculate_sha256_for_file(path):
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sha256 = hashlib.sha256()
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with open(path, 'rb') as f:
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for block in iter(lambda: f.read(filecmp.BUFSIZE), b''):
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sha256.update(block)
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return sha256.hexdigest()
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def get_default_environment():
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"""
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Tries to return an active Virtualenv or conda environment.
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If there is no VIRTUAL_ENV variable or no CONDA_PREFIX variable set
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set it will return the latest Python version installed on the system. This
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makes it possible to use as many new Python features as possible when using
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autocompletion and other functionality.
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:returns: :class:`.Environment`
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"""
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virtual_env = _get_virtual_env_from_var()
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if virtual_env is not None:
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return virtual_env
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conda_env = _get_virtual_env_from_var(_CONDA_VAR)
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if conda_env is not None:
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return conda_env
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return _try_get_same_env()
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def _try_get_same_env():
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env = SameEnvironment()
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if not os.path.basename(env.executable).lower().startswith('python'):
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# This tries to counter issues with embedding. In some cases (e.g.
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# VIM's Python Mac/Windows, sys.executable is /foo/bar/vim. This
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# happens, because for Mac a function called `_NSGetExecutablePath` is
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# used and for Windows `GetModuleFileNameW`. These are both platform
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# specific functions. For all other systems sys.executable should be
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# alright. However here we try to generalize:
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#
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# 1. Check if the executable looks like python (heuristic)
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# 2. In case it's not try to find the executable
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# 3. In case we don't find it use an interpreter environment.
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#
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# The last option will always work, but leads to potential crashes of
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# Jedi - which is ok, because it happens very rarely and even less,
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# because the code below should work for most cases.
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if os.name == 'nt':
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# The first case would be a virtualenv and the second a normal
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# Python installation.
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checks = (r'Scripts\python.exe', 'python.exe')
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else:
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# For unix it looks like Python is always in a bin folder.
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checks = (
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'bin/python%s.%s' % (sys.version_info[0], sys.version[1]),
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'bin/python%s' % (sys.version_info[0]),
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'bin/python',
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)
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for check in checks:
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guess = os.path.join(sys.exec_prefix, check)
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if os.path.isfile(guess):
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# Bingo - We think we have our Python.
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return Environment(guess)
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# It looks like there is no reasonable Python to be found.
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return InterpreterEnvironment()
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# If no virtualenv is found, use the environment we're already
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# using.
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return env
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def get_cached_default_environment():
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var = os.environ.get('VIRTUAL_ENV') or os.environ.get(_CONDA_VAR)
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environment = _get_cached_default_environment()
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# Under macOS in some cases - notably when using Pipenv - the
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# sys.prefix of the virtualenv is /path/to/env/bin/.. instead of
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# /path/to/env so we need to fully resolve the paths in order to
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# compare them.
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if var and os.path.realpath(var) != os.path.realpath(environment.path):
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_get_cached_default_environment.clear_cache()
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return _get_cached_default_environment()
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return environment
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@time_cache(seconds=10 * 60) # 10 Minutes
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def _get_cached_default_environment():
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try:
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return get_default_environment()
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except InvalidPythonEnvironment:
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# It's possible that `sys.executable` is wrong. Typically happens
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# when Jedi is used in an executable that embeds Python. For further
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# information, have a look at:
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# https://github.com/davidhalter/jedi/issues/1531
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return InterpreterEnvironment()
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def find_virtualenvs(paths=None, **kwargs):
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"""
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:param paths: A list of paths in your file system to be scanned for
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Virtualenvs. It will search in these paths and potentially execute the
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Python binaries.
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:param safe: Default True. In case this is False, it will allow this
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function to execute potential `python` environments. An attacker might
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be able to drop an executable in a path this function is searching by
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default. If the executable has not been installed by root, it will not
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be executed.
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:param use_environment_vars: Default True. If True, the VIRTUAL_ENV
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variable will be checked if it contains a valid VirtualEnv.
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CONDA_PREFIX will be checked to see if it contains a valid conda
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environment.
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:yields: :class:`.Environment`
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"""
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def py27_comp(paths=None, safe=True, use_environment_vars=True):
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if paths is None:
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paths = []
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_used_paths = set()
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if use_environment_vars:
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# Using this variable should be safe, because attackers might be
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# able to drop files (via git) but not environment variables.
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virtual_env = _get_virtual_env_from_var()
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if virtual_env is not None:
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yield virtual_env
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_used_paths.add(virtual_env.path)
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conda_env = _get_virtual_env_from_var(_CONDA_VAR)
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if conda_env is not None:
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yield conda_env
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_used_paths.add(conda_env.path)
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for directory in paths:
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if not os.path.isdir(directory):
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continue
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directory = os.path.abspath(directory)
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for path in os.listdir(directory):
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path = os.path.join(directory, path)
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if path in _used_paths:
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# A path shouldn't be inferred twice.
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continue
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_used_paths.add(path)
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try:
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executable = _get_executable_path(path, safe=safe)
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yield Environment(executable)
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except InvalidPythonEnvironment:
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pass
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return py27_comp(paths, **kwargs)
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def find_system_environments():
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"""
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Ignores virtualenvs and returns the Python versions that were installed on
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your system. This might return nothing, if you're running Python e.g. from
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a portable version.
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The environments are sorted from latest to oldest Python version.
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:yields: :class:`.Environment`
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"""
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for version_string in _SUPPORTED_PYTHONS:
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try:
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yield get_system_environment(version_string)
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except InvalidPythonEnvironment:
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pass
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# TODO: this function should probably return a list of environments since
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# multiple Python installations can be found on a system for the same version.
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def get_system_environment(version):
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"""
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Return the first Python environment found for a string of the form 'X.Y'
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where X and Y are the major and minor versions of Python.
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:raises: :exc:`.InvalidPythonEnvironment`
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:returns: :class:`.Environment`
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"""
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exe = which('python' + version)
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if exe:
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if exe == sys.executable:
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return SameEnvironment()
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return Environment(exe)
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if os.name == 'nt':
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for exe in _get_executables_from_windows_registry(version):
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try:
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return Environment(exe)
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except InvalidPythonEnvironment:
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pass
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raise InvalidPythonEnvironment("Cannot find executable python%s." % version)
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def create_environment(path, safe=True):
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"""
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Make it possible to manually create an Environment object by specifying a
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Virtualenv path or an executable path.
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:raises: :exc:`.InvalidPythonEnvironment`
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:returns: :class:`.Environment`
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"""
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if os.path.isfile(path):
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_assert_safe(path, safe)
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return Environment(path)
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return Environment(_get_executable_path(path, safe=safe))
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def _get_executable_path(path, safe=True):
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"""
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Returns None if it's not actually a virtual env.
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"""
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if os.name == 'nt':
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python = os.path.join(path, 'Scripts', 'python.exe')
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else:
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python = os.path.join(path, 'bin', 'python')
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if not os.path.exists(python):
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raise InvalidPythonEnvironment("%s seems to be missing." % python)
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_assert_safe(python, safe)
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return python
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def _get_executables_from_windows_registry(version):
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# The winreg module is named _winreg on Python 2.
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try:
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import winreg
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except ImportError:
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import _winreg as winreg
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# TODO: support Python Anaconda.
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sub_keys = [
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r'SOFTWARE\Python\PythonCore\{version}\InstallPath',
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r'SOFTWARE\Wow6432Node\Python\PythonCore\{version}\InstallPath',
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r'SOFTWARE\Python\PythonCore\{version}-32\InstallPath',
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r'SOFTWARE\Wow6432Node\Python\PythonCore\{version}-32\InstallPath'
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]
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for root_key in [winreg.HKEY_CURRENT_USER, winreg.HKEY_LOCAL_MACHINE]:
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for sub_key in sub_keys:
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sub_key = sub_key.format(version=version)
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try:
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with winreg.OpenKey(root_key, sub_key) as key:
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prefix = winreg.QueryValueEx(key, '')[0]
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exe = os.path.join(prefix, 'python.exe')
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if os.path.isfile(exe):
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yield exe
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except WindowsError:
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pass
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def _assert_safe(executable_path, safe):
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if safe and not _is_safe(executable_path):
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raise InvalidPythonEnvironment(
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"The python binary is potentially unsafe.")
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def _is_safe(executable_path):
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# Resolve sym links. A venv typically is a symlink to a known Python
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# binary. Only virtualenvs copy symlinks around.
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real_path = os.path.realpath(executable_path)
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if _is_unix_safe_simple(real_path):
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return True
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# Just check the list of known Python versions. If it's not in there,
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|
# it's likely an attacker or some Python that was not properly
|
||
|
# installed in the system.
|
||
|
for environment in find_system_environments():
|
||
|
if environment.executable == real_path:
|
||
|
return True
|
||
|
|
||
|
# If the versions don't match, just compare the binary files. If we
|
||
|
# don't do that, only venvs will be working and not virtualenvs.
|
||
|
# venvs are symlinks while virtualenvs are actual copies of the
|
||
|
# Python files.
|
||
|
# This still means that if the system Python is updated and the
|
||
|
# virtualenv's Python is not (which is probably never going to get
|
||
|
# upgraded), it will not work with Jedi. IMO that's fine, because
|
||
|
# people should just be using venv. ~ dave
|
||
|
if environment._sha256 == _calculate_sha256_for_file(real_path):
|
||
|
return True
|
||
|
return False
|
||
|
|
||
|
|
||
|
def _is_unix_safe_simple(real_path):
|
||
|
if _is_unix_admin():
|
||
|
# In case we are root, just be conservative and
|
||
|
# only execute known paths.
|
||
|
return any(real_path.startswith(p) for p in _SAFE_PATHS)
|
||
|
|
||
|
uid = os.stat(real_path).st_uid
|
||
|
# The interpreter needs to be owned by root. This means that it wasn't
|
||
|
# written by a user and therefore attacking Jedi is not as simple.
|
||
|
# The attack could look like the following:
|
||
|
# 1. A user clones a repository.
|
||
|
# 2. The repository has an innocent looking folder called foobar. jedi
|
||
|
# searches for the folder and executes foobar/bin/python --version if
|
||
|
# there's also a foobar/bin/activate.
|
||
|
# 3. The attacker has gained code execution, since he controls
|
||
|
# foobar/bin/python.
|
||
|
return uid == 0
|
||
|
|
||
|
|
||
|
def _is_unix_admin():
|
||
|
try:
|
||
|
return os.getuid() == 0
|
||
|
except AttributeError:
|
||
|
return False # Windows
|