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issue #590: rework ParentEnumerationMethod to recursively handle bad modules

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In the worst case it will start with sys.path and resolve everything
from scratch.
new-serialization
David Wilson 5 years ago
parent 4caca80962
commit bdf6f1b9a9
3 changed files with 140 additions and 42 deletions
Show Stats Download Patch File Download Diff File

133
mitogen/master.py
Unescape Escape View File

@ -535,18 +535,20 @@ class SysModulesMethod(FinderMethod):
Find `fullname` using its :data:`__file__` attribute.
"""
module = sys.modules.get(fullname)
LOG.debug('_get_module_via_sys_modules(%r) -> %r', fullname, module)
if getattr(module, '__name__', None) != fullname:
LOG.debug('sys.modules[%r].__name__ does not match %r, assuming '
'this is a hacky module alias and ignoring it',
fullname, fullname)
return
if not isinstance(module, types.ModuleType):
LOG.debug('%r: sys.modules[%r] absent or not a regular module',
self, fullname)
return
LOG.debug('_get_module_via_sys_modules(%r) -> %r', fullname, module)
alleged_name = getattr(module, '__name__', None)
if alleged_name != fullname:
LOG.debug('sys.modules[%r].__name__ is incorrect, assuming '
'this is a hacky module alias and ignoring it. '
'Got %r, module object: %r',
fullname, alleged_name, module)
return
path = _py_filename(getattr(module, '__file__', ''))
if not path:
return
@ -573,43 +575,57 @@ class SysModulesMethod(FinderMethod):
class ParentEnumerationMethod(FinderMethod):
"""
Attempt to fetch source code by examining the module's (hopefully less
insane) parent package. Required for older versions of
:mod:`ansible.compat.six`, :mod:`plumbum.colors`, and Ansible 2.8
:mod:`ansible.module_utils.distro`.
insane) parent package, and if no insane parents exist, simply use
:mod:`sys.path` to search for it from scratch on the filesystem using the
normal Python lookup mechanism.
This is required for older versions of :mod:`ansible.compat.six`,
:mod:`plumbum.colors`, Ansible 2.8 :mod:`ansible.module_utils.distro` and
its submodule :mod:`ansible.module_utils.distro._distro`.
When some package dynamically replaces itself in :data:`sys.modules`, but
only conditionally according to some program logic, it is possible that
children may attempt to load modules and subpackages from it that can no
longer be resolved by examining a (corrupted) parent.
For cases like :mod:`ansible.module_utils.distro`, this must handle cases
where a package transmuted itself into a totally unrelated module during
import and vice versa.
import and vice versa, where :data:`sys.modules` is replaced with junk that
makes it impossible to discover the loaded module using the in-memory
module object or any parent package's :data:`__path__`, since they have all
been overwritten. Some men just want to watch the world burn.
"""
def find(self, fullname):
def _find_sane_parent(self, fullname):
"""
See implementation for a description of how this works.
Iteratively search :data:`sys.modules` for the least indirect parent of
`fullname` that is loaded and contains a :data:`__path__` attribute.
:return:
`(parent_name, path, modpath)` tuple, where:
* `modname`: canonical name of the found package, or the empty
string if none is found.
* `search_path`: :data:`__path__` attribute of the least
indirect parent found, or :data:`None` if no indirect parent
was found.
* `modpath`: list of module name components leading from `path`
to the target module.
"""
if fullname not in sys.modules:
# Don't attempt this unless a module really exists in sys.modules,
# else we could return junk.
return
pkgname, _, modname = str_rpartition(to_text(fullname), u'.')
pkg = sys.modules.get(pkgname)
if pkg is None or not hasattr(pkg, '__file__'):
LOG.debug('%r: %r is not a package or lacks __file__ attribute',
self, pkgname)
return
pkg_path = [os.path.dirname(pkg.__file__)]
try:
fp, path, (suffix, _, kind) = imp.find_module(modname, pkg_path)
except ImportError:
e = sys.exc_info()[1]
LOG.debug('%r: imp.find_module(%r, %r) -> %s',
self, modname, [pkg_path], e)
return None
if kind == imp.PKG_DIRECTORY:
return self._found_package(fullname, path)
else:
return self._found_module(fullname, path, fp)
path = None
modpath = []
while True:
pkgname, _, modname = str_rpartition(to_text(fullname), u'.')
modpath.insert(0, modname)
if not pkgname:
return [], None, modpath
pkg = sys.modules.get(pkgname)
path = getattr(pkg, '__path__', None)
if pkg and path:
return pkgname.split('.'), path, modpath
LOG.debug('%r: %r lacks __path__ attribute', self, pkgname)
fullname = pkgname
def _found_package(self, fullname, path):
path = os.path.join(path, '__init__.py')
@ -638,6 +654,47 @@ class ParentEnumerationMethod(FinderMethod):
source = source.encode('utf-8')
return path, source, is_pkg
def _find_one_component(self, modname, search_path):
try:
#fp, path, (suffix, _, kind) = imp.find_module(modname, search_path)
return imp.find_module(modname, search_path)
except ImportError:
e = sys.exc_info()[1]
LOG.debug('%r: imp.find_module(%r, %r) -> %s',
self, modname, [search_path], e)
return None
def find(self, fullname):
"""
See implementation for a description of how this works.
"""
#if fullname not in sys.modules:
# Don't attempt this unless a module really exists in sys.modules,
# else we could return junk.
#return
fullname = to_text(fullname)
modname, search_path, modpath = self._find_sane_parent(fullname)
while True:
tup = self._find_one_component(modpath.pop(0), search_path)
if tup is None:
return None
fp, path, (suffix, _, kind) = tup
if modpath:
# Still more components to descent. Result must be a package
if fp:
fp.close()
if kind != imp.PKG_DIRECTORY:
LOG.debug('%r: %r appears to be child of non-package %r',
self, fullname, path)
return None
search_path = [path]
elif kind == imp.PKG_DIRECTORY:
return self._found_package(fullname, path)
else:
return self._found_module(fullname, path, fp)
class ModuleFinder(object):
"""

39
tests/module_finder_test.py
Unescape Escape View File

@ -180,6 +180,7 @@ class GetModuleViaParentEnumerationTest(testlib.TestCase):
'pkg_like_ansible.module_utils.distro._distro'
)
# ensure we can resolve the subpackage.
path, src, is_pkg = self.call('pkg_like_ansible.module_utils.distro')
modpath = os.path.join(MODS_DIR,
'pkg_like_ansible/module_utils/distro/__init__.py')
@ -187,6 +188,44 @@ class GetModuleViaParentEnumerationTest(testlib.TestCase):
self.assertEquals(src, open(modpath, 'rb').read())
self.assertEquals(is_pkg, True)
# ensure we can resolve a child of the subpackage.
path, src, is_pkg = self.call(
'pkg_like_ansible.module_utils.distro._distro'
)
modpath = os.path.join(MODS_DIR,
'pkg_like_ansible/module_utils/distro/_distro.py')
self.assertEquals(path, modpath)
self.assertEquals(src, open(modpath, 'rb').read())
self.assertEquals(is_pkg, False)
def test_ansible_module_utils_system_distro_succeeds(self):
# #590: a package that turns itself into a module.
# #590: a package that turns itself into a module.
import pkg_like_ansible.module_utils.sys_distro as d
self.assertEquals(d.I_AM, "the system module that replaced the subpackage")
self.assertEquals(
sys.modules['pkg_like_ansible.module_utils.sys_distro'].__name__,
'system_distro'
)
# ensure we can resolve the subpackage.
path, src, is_pkg = self.call('pkg_like_ansible.module_utils.sys_distro')
modpath = os.path.join(MODS_DIR,
'pkg_like_ansible/module_utils/sys_distro/__init__.py')
self.assertEquals(path, modpath)
self.assertEquals(src, open(modpath, 'rb').read())
self.assertEquals(is_pkg, True)
# ensure we can resolve a child of the subpackage.
path, src, is_pkg = self.call(
'pkg_like_ansible.module_utils.sys_distro._distro'
)
modpath = os.path.join(MODS_DIR,
'pkg_like_ansible/module_utils/sys_distro/_distro.py')
self.assertEquals(path, modpath)
self.assertEquals(src, open(modpath, 'rb').read())
self.assertEquals(is_pkg, False)
class ResolveRelPathTest(testlib.TestCase):
klass = mitogen.master.ModuleFinder

10
tests/responder_test.py
Unescape Escape View File

@ -158,14 +158,16 @@ class BrokenModulesTest(testlib.TestCase):
self.assertEquals(1, len(router._async_route.mock_calls))
self.assertEquals(1, responder.get_module_count)
self.assertEquals(0, responder.good_load_module_count)
self.assertEquals(0, responder.good_load_module_size)
self.assertEquals(1, responder.bad_load_module_count)
self.assertEquals(1, responder.good_load_module_count)
self.assertEquals(7642, responder.good_load_module_size)
self.assertEquals(0, responder.bad_load_module_count)
call = router._async_route.mock_calls[0]
msg, = call[1]
self.assertEquals(mitogen.core.LOAD_MODULE, msg.handle)
self.assertIsInstance(msg.unpickle(), tuple)
tup = msg.unpickle()
self.assertIsInstance(tup, tuple)
class ForwardTest(testlib.RouterMixin, testlib.TestCase):

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