mirror of
https://github.com/python/cpython.git
synced 2025-10-31 18:28:49 +00:00
294 lines
12 KiB
Python
294 lines
12 KiB
Python
"""runpy.py - locating and running Python code using the module namespace
|
|
|
|
Provides support for locating and running Python scripts using the Python
|
|
module namespace instead of the native filesystem.
|
|
|
|
This allows Python code to play nicely with non-filesystem based PEP 302
|
|
importers when locating support scripts as well as when importing modules.
|
|
"""
|
|
# Written by Nick Coghlan <ncoghlan at gmail.com>
|
|
# to implement PEP 338 (Executing Modules as Scripts)
|
|
|
|
|
|
import sys
|
|
import importlib.machinery # importlib first so we can test #15386 via -m
|
|
import importlib.util
|
|
import types
|
|
from pkgutil import read_code, get_importer
|
|
|
|
__all__ = [
|
|
"run_module", "run_path",
|
|
]
|
|
|
|
class _TempModule(object):
|
|
"""Temporarily replace a module in sys.modules with an empty namespace"""
|
|
def __init__(self, mod_name):
|
|
self.mod_name = mod_name
|
|
self.module = types.ModuleType(mod_name)
|
|
self._saved_module = []
|
|
|
|
def __enter__(self):
|
|
mod_name = self.mod_name
|
|
try:
|
|
self._saved_module.append(sys.modules[mod_name])
|
|
except KeyError:
|
|
pass
|
|
sys.modules[mod_name] = self.module
|
|
return self
|
|
|
|
def __exit__(self, *args):
|
|
if self._saved_module:
|
|
sys.modules[self.mod_name] = self._saved_module[0]
|
|
else:
|
|
del sys.modules[self.mod_name]
|
|
self._saved_module = []
|
|
|
|
class _ModifiedArgv0(object):
|
|
def __init__(self, value):
|
|
self.value = value
|
|
self._saved_value = self._sentinel = object()
|
|
|
|
def __enter__(self):
|
|
if self._saved_value is not self._sentinel:
|
|
raise RuntimeError("Already preserving saved value")
|
|
self._saved_value = sys.argv[0]
|
|
sys.argv[0] = self.value
|
|
|
|
def __exit__(self, *args):
|
|
self.value = self._sentinel
|
|
sys.argv[0] = self._saved_value
|
|
|
|
# TODO: Replace these helpers with importlib._bootstrap_external functions.
|
|
def _run_code(code, run_globals, init_globals=None,
|
|
mod_name=None, mod_spec=None,
|
|
pkg_name=None, script_name=None):
|
|
"""Helper to run code in nominated namespace"""
|
|
if init_globals is not None:
|
|
run_globals.update(init_globals)
|
|
if mod_spec is None:
|
|
loader = None
|
|
fname = script_name
|
|
cached = None
|
|
else:
|
|
loader = mod_spec.loader
|
|
fname = mod_spec.origin
|
|
cached = mod_spec.cached
|
|
if pkg_name is None:
|
|
pkg_name = mod_spec.parent
|
|
run_globals.update(__name__ = mod_name,
|
|
__file__ = fname,
|
|
__cached__ = cached,
|
|
__doc__ = None,
|
|
__loader__ = loader,
|
|
__package__ = pkg_name,
|
|
__spec__ = mod_spec)
|
|
exec(code, run_globals)
|
|
return run_globals
|
|
|
|
def _run_module_code(code, init_globals=None,
|
|
mod_name=None, mod_spec=None,
|
|
pkg_name=None, script_name=None):
|
|
"""Helper to run code in new namespace with sys modified"""
|
|
fname = script_name if mod_spec is None else mod_spec.origin
|
|
with _TempModule(mod_name) as temp_module, _ModifiedArgv0(fname):
|
|
mod_globals = temp_module.module.__dict__
|
|
_run_code(code, mod_globals, init_globals,
|
|
mod_name, mod_spec, pkg_name, script_name)
|
|
# Copy the globals of the temporary module, as they
|
|
# may be cleared when the temporary module goes away
|
|
return mod_globals.copy()
|
|
|
|
# Helper to get the full name, spec and code for a module
|
|
def _get_module_details(mod_name, error=ImportError):
|
|
if mod_name.startswith("."):
|
|
raise error("Relative module names not supported")
|
|
pkg_name, _, _ = mod_name.rpartition(".")
|
|
if pkg_name:
|
|
# Try importing the parent to avoid catching initialization errors
|
|
try:
|
|
__import__(pkg_name)
|
|
except ImportError as e:
|
|
# If the parent or higher ancestor package is missing, let the
|
|
# error be raised by find_spec() below and then be caught. But do
|
|
# not allow other errors to be caught.
|
|
if e.name is None or (e.name != pkg_name and
|
|
not pkg_name.startswith(e.name + ".")):
|
|
raise
|
|
# Warn if the module has already been imported under its normal name
|
|
existing = sys.modules.get(mod_name)
|
|
if existing is not None and not hasattr(existing, "__path__"):
|
|
from warnings import warn
|
|
msg = "{mod_name!r} found in sys.modules after import of " \
|
|
"package {pkg_name!r}, but prior to execution of " \
|
|
"{mod_name!r}; this may result in unpredictable " \
|
|
"behaviour".format(mod_name=mod_name, pkg_name=pkg_name)
|
|
warn(RuntimeWarning(msg))
|
|
|
|
try:
|
|
spec = importlib.util.find_spec(mod_name)
|
|
except (ImportError, AttributeError, TypeError, ValueError) as ex:
|
|
# This hack fixes an impedance mismatch between pkgutil and
|
|
# importlib, where the latter raises other errors for cases where
|
|
# pkgutil previously raised ImportError
|
|
msg = "Error while finding module specification for {!r} ({}: {})"
|
|
raise error(msg.format(mod_name, type(ex).__name__, ex)) from ex
|
|
if spec is None:
|
|
raise error("No module named %s" % mod_name)
|
|
if spec.submodule_search_locations is not None:
|
|
if mod_name == "__main__" or mod_name.endswith(".__main__"):
|
|
raise error("Cannot use package as __main__ module")
|
|
try:
|
|
pkg_main_name = mod_name + ".__main__"
|
|
return _get_module_details(pkg_main_name, error)
|
|
except error as e:
|
|
if mod_name not in sys.modules:
|
|
raise # No module loaded; being a package is irrelevant
|
|
raise error(("%s; %r is a package and cannot " +
|
|
"be directly executed") %(e, mod_name))
|
|
loader = spec.loader
|
|
if loader is None:
|
|
raise error("%r is a namespace package and cannot be executed"
|
|
% mod_name)
|
|
try:
|
|
code = loader.get_code(mod_name)
|
|
except ImportError as e:
|
|
raise error(format(e)) from e
|
|
if code is None:
|
|
raise error("No code object available for %s" % mod_name)
|
|
return mod_name, spec, code
|
|
|
|
class _Error(Exception):
|
|
"""Error that _run_module_as_main() should report without a traceback"""
|
|
|
|
# XXX ncoghlan: Should this be documented and made public?
|
|
# (Current thoughts: don't repeat the mistake that lead to its
|
|
# creation when run_module() no longer met the needs of
|
|
# mainmodule.c, but couldn't be changed because it was public)
|
|
def _run_module_as_main(mod_name, alter_argv=True):
|
|
"""Runs the designated module in the __main__ namespace
|
|
|
|
Note that the executed module will have full access to the
|
|
__main__ namespace. If this is not desirable, the run_module()
|
|
function should be used to run the module code in a fresh namespace.
|
|
|
|
At the very least, these variables in __main__ will be overwritten:
|
|
__name__
|
|
__file__
|
|
__cached__
|
|
__loader__
|
|
__package__
|
|
"""
|
|
try:
|
|
if alter_argv or mod_name != "__main__": # i.e. -m switch
|
|
mod_name, mod_spec, code = _get_module_details(mod_name, _Error)
|
|
else: # i.e. directory or zipfile execution
|
|
mod_name, mod_spec, code = _get_main_module_details(_Error)
|
|
except _Error as exc:
|
|
msg = "%s: %s" % (sys.executable, exc)
|
|
sys.exit(msg)
|
|
main_globals = sys.modules["__main__"].__dict__
|
|
if alter_argv:
|
|
sys.argv[0] = mod_spec.origin
|
|
return _run_code(code, main_globals, None,
|
|
"__main__", mod_spec)
|
|
|
|
def run_module(mod_name, init_globals=None,
|
|
run_name=None, alter_sys=False):
|
|
"""Execute a module's code without importing it
|
|
|
|
Returns the resulting top level namespace dictionary
|
|
"""
|
|
mod_name, mod_spec, code = _get_module_details(mod_name)
|
|
if run_name is None:
|
|
run_name = mod_name
|
|
if alter_sys:
|
|
return _run_module_code(code, init_globals, run_name, mod_spec)
|
|
else:
|
|
# Leave the sys module alone
|
|
return _run_code(code, {}, init_globals, run_name, mod_spec)
|
|
|
|
def _get_main_module_details(error=ImportError):
|
|
# Helper that gives a nicer error message when attempting to
|
|
# execute a zipfile or directory by invoking __main__.py
|
|
# Also moves the standard __main__ out of the way so that the
|
|
# preexisting __loader__ entry doesn't cause issues
|
|
main_name = "__main__"
|
|
saved_main = sys.modules[main_name]
|
|
del sys.modules[main_name]
|
|
try:
|
|
return _get_module_details(main_name)
|
|
except ImportError as exc:
|
|
if main_name in str(exc):
|
|
raise error("can't find %r module in %r" %
|
|
(main_name, sys.path[0])) from exc
|
|
raise
|
|
finally:
|
|
sys.modules[main_name] = saved_main
|
|
|
|
|
|
def _get_code_from_file(run_name, fname):
|
|
# Check for a compiled file first
|
|
with open(fname, "rb") as f:
|
|
code = read_code(f)
|
|
if code is None:
|
|
# That didn't work, so try it as normal source code
|
|
with open(fname, "rb") as f:
|
|
code = compile(f.read(), fname, 'exec')
|
|
return code, fname
|
|
|
|
def run_path(path_name, init_globals=None, run_name=None):
|
|
"""Execute code located at the specified filesystem location
|
|
|
|
Returns the resulting top level namespace dictionary
|
|
|
|
The file path may refer directly to a Python script (i.e.
|
|
one that could be directly executed with execfile) or else
|
|
it may refer to a zipfile or directory containing a top
|
|
level __main__.py script.
|
|
"""
|
|
if run_name is None:
|
|
run_name = "<run_path>"
|
|
pkg_name = run_name.rpartition(".")[0]
|
|
importer = get_importer(path_name)
|
|
# Trying to avoid importing imp so as to not consume the deprecation warning.
|
|
is_NullImporter = False
|
|
if type(importer).__module__ == 'imp':
|
|
if type(importer).__name__ == 'NullImporter':
|
|
is_NullImporter = True
|
|
if isinstance(importer, type(None)) or is_NullImporter:
|
|
# Not a valid sys.path entry, so run the code directly
|
|
# execfile() doesn't help as we want to allow compiled files
|
|
code, fname = _get_code_from_file(run_name, path_name)
|
|
return _run_module_code(code, init_globals, run_name,
|
|
pkg_name=pkg_name, script_name=fname)
|
|
else:
|
|
# Finder is defined for path, so add it to
|
|
# the start of sys.path
|
|
sys.path.insert(0, path_name)
|
|
try:
|
|
# Here's where things are a little different from the run_module
|
|
# case. There, we only had to replace the module in sys while the
|
|
# code was running and doing so was somewhat optional. Here, we
|
|
# have no choice and we have to remove it even while we read the
|
|
# code. If we don't do this, a __loader__ attribute in the
|
|
# existing __main__ module may prevent location of the new module.
|
|
mod_name, mod_spec, code = _get_main_module_details()
|
|
with _TempModule(run_name) as temp_module, \
|
|
_ModifiedArgv0(path_name):
|
|
mod_globals = temp_module.module.__dict__
|
|
return _run_code(code, mod_globals, init_globals,
|
|
run_name, mod_spec, pkg_name).copy()
|
|
finally:
|
|
try:
|
|
sys.path.remove(path_name)
|
|
except ValueError:
|
|
pass
|
|
|
|
|
|
if __name__ == "__main__":
|
|
# Run the module specified as the next command line argument
|
|
if len(sys.argv) < 2:
|
|
print("No module specified for execution", file=sys.stderr)
|
|
else:
|
|
del sys.argv[0] # Make the requested module sys.argv[0]
|
|
_run_module_as_main(sys.argv[0])
|