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Issue #14285: Do not catch __init__.py exceptions in runpy 

Initialize package before calling find_spec() for __main__, so that we do not
incorrectly handle exceptions from __init__.py. When runpy is used from the
Python CLI, use an internal exception rather than ImportError, to avoid
catching unexpected exceptions.

Also remove exception message rewriting in _run_module_as_main(), because it
seems to be redundant with the _get_main_module_details() function.
This commit is contained in:
Martin Panter 2015-12-03 01:23:10 +00:00
parent 6648bf5661
commit 657257edb6
4 changed files with 110 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
Lib/runpy.py
View File

@ -99,7 +99,7 @@ def _run_module_code(code, init_globals=None,
return mod_globals.copy()
# Helper to get the loader, code and filename for a module
def _get_module_details(mod_name):
def _get_module_details(mod_name, error=ImportError):
try:
spec = importlib.util.find_spec(mod_name)
except (ImportError, AttributeError, TypeError, ValueError) as ex:
@ -107,27 +107,34 @@ def _get_module_details(mod_name):
# importlib, where the latter raises other errors for cases where
# pkgutil previously raised ImportError
msg = "Error while finding spec for {!r} ({}: {})"
raise ImportError(msg.format(mod_name, type(ex), ex)) from ex
raise error(msg.format(mod_name, type(ex), ex)) from ex
if spec is None:
raise ImportError("No module named %s" % mod_name)
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 ImportError("Cannot use package as __main__ module")
raise error("Cannot use package as __main__ module")
__import__(mod_name) # Do not catch exceptions initializing package
try:
pkg_main_name = mod_name + ".__main__"
return _get_module_details(pkg_main_name)
except ImportError as e:
raise ImportError(("%s; %r is a package and cannot " +
raise error(("%s; %r is a package and cannot " +
"be directly executed") %(e, mod_name))
loader = spec.loader
if loader is None:
raise ImportError("%r is a namespace package and cannot be executed"
raise error("%r is a namespace package and cannot be executed"
% mod_name)
code = loader.get_code(mod_name)
try:
code = loader.get_code(mod_name)
except ImportError as e:
raise error(format(e)) from e
if code is None:
raise ImportError("No code object available for %s" % mod_name)
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
@ -148,20 +155,11 @@ def _run_module_as_main(mod_name, alter_argv=True):
"""
try:
if alter_argv or mod_name != "__main__": # i.e. -m switch
mod_name, mod_spec, code = _get_module_details(mod_name)
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()
except ImportError as exc:
# Try to provide a good error message
# for directories, zip files and the -m switch
if alter_argv:
# For -m switch, just display the exception
info = str(exc)
else:
# For directories/zipfiles, let the user
# know what the code was looking for
info = "can't find '__main__' module in %r" % sys.argv[0]
msg = "%s: %s" % (sys.executable, info)
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:
@ -184,7 +182,7 @@ def run_module(mod_name, init_globals=None,
# Leave the sys module alone
return _run_code(code, {}, init_globals, run_name, mod_spec)
def _get_main_module_details():
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
@ -196,7 +194,7 @@ def _get_main_module_details():
return _get_module_details(main_name)
except ImportError as exc:
if main_name in str(exc):
raise ImportError("can't find %r module in %r" %
raise error("can't find %r module in %r" %
(main_name, sys.path[0])) from exc
raise
finally:

71
Lib/test/test_cmd_line_script.py
View File

@ -397,20 +397,73 @@ class CmdLineTest(unittest.TestCase):
script_name, script_name, '', '',
importlib.machinery.SourceFileLoader)
@contextlib.contextmanager
def setup_test_pkg(self, *args):
with support.temp_dir() as script_dir, \
support.change_cwd(path=script_dir):
pkg_dir = os.path.join(script_dir, 'test_pkg')
make_pkg(pkg_dir, *args)
yield pkg_dir
def check_dash_m_failure(self, *args):
rc, out, err = assert_python_failure('-m', *args, __isolated=False)
if verbose > 1:
print(repr(out))
self.assertEqual(rc, 1)
return err
def test_dash_m_error_code_is_one(self):
# If a module is invoked with the -m command line flag
# and results in an error that the return code to the
# shell is '1'
with support.temp_dir() as script_dir:
with support.change_cwd(path=script_dir):
pkg_dir = os.path.join(script_dir, 'test_pkg')
make_pkg(pkg_dir)
script_name = _make_test_script(pkg_dir, 'other',
"if __name__ == '__main__': raise ValueError")
rc, out, err = assert_python_failure('-m', 'test_pkg.other', *example_args)
if verbose > 1:
print(repr(out))
with self.setup_test_pkg() as pkg_dir:
script_name = _make_test_script(pkg_dir, 'other',
"if __name__ == '__main__': raise ValueError")
err = self.check_dash_m_failure('test_pkg.other', *example_args)
self.assertIn(b'ValueError', err)
def test_dash_m_errors(self):
# Exercise error reporting for various invalid package executions
tests = (
('builtins', br'No code object available'),
('builtins.x', br'Error while finding spec.*AttributeError'),
('builtins.x.y', br'Error while finding spec.*'
br'ImportError.*No module named.*not a package'),
('os.path', br'loader.*cannot handle'),
('importlib', br'No module named.*'
br'is a package and cannot be directly executed'),
('importlib.nonexistant', br'No module named'),
)
for name, regex in tests:
with self.subTest(name):
rc, _, err = assert_python_failure('-m', name)
self.assertEqual(rc, 1)
self.assertRegex(err, regex)
self.assertNotIn(b'Traceback', err)
def test_dash_m_init_traceback(self):
# These were wrapped in an ImportError and tracebacks were
# suppressed; see Issue 14285
exceptions = (ImportError, AttributeError, TypeError, ValueError)
for exception in exceptions:
exception = exception.__name__
init = "raise {0}('Exception in __init__.py')".format(exception)
with self.subTest(exception), \
self.setup_test_pkg(init) as pkg_dir:
err = self.check_dash_m_failure('test_pkg')
self.assertIn(exception.encode('ascii'), err)
self.assertIn(b'Exception in __init__.py', err)
self.assertIn(b'Traceback', err)
def test_dash_m_main_traceback(self):
# Ensure that an ImportError's traceback is reported
with self.setup_test_pkg() as pkg_dir:
main = "raise ImportError('Exception in __main__ module')"
_make_test_script(pkg_dir, '__main__', main)
err = self.check_dash_m_failure('test_pkg')
self.assertIn(b'ImportError', err)
self.assertIn(b'Exception in __main__ module', err)
self.assertIn(b'Traceback', err)
def test_pep_409_verbiage(self):
# Make sure PEP 409 syntax properly suppresses

22
Lib/test/test_runpy.py
View File

@ -439,6 +439,28 @@ from ..uncle.cousin import nephew
if verbose > 1: print("Testing package depth:", depth)
self._check_package(depth)
def test_run_package_init_exceptions(self):
# These were previously wrapped in an ImportError; see Issue 14285
result = self._make_pkg("", 1, "__main__")
pkg_dir, _, mod_name, _ = result
mod_name = mod_name.replace(".__main__", "")
self.addCleanup(self._del_pkg, pkg_dir, 1, mod_name)
init = os.path.join(pkg_dir, "__runpy_pkg__", "__init__.py")
exceptions = (ImportError, AttributeError, TypeError, ValueError)
for exception in exceptions:
name = exception.__name__
with self.subTest(name):
source = "raise {0}('{0} in __init__.py.')".format(name)
with open(init, "wt", encoding="ascii") as mod_file:
mod_file.write(source)
try:
run_module(mod_name)
except exception as err:
self.assertNotIn("finding spec", format(err))
else:
self.fail("Nothing raised; expected {}".format(name))
def test_run_package_in_namespace_package(self):
for depth in range(1, 4):
if verbose > 1: print("Testing package depth:", depth)

5
Misc/NEWS
View File

@ -22,6 +22,11 @@ Core and Builtins
Library
-------
- Issue #14285: When executing a package with the "python -m package" option,
and package initialization fails, a proper traceback is now reported. The
"runpy" module now lets exceptions from package initialization pass back to
the caller, rather than raising ImportError.
- Issue #25177: Fixed problem with the mean of very small and very large
numbers. As a side effect, statistics.mean and statistics.variance should
be significantly faster.