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bpo-21736: Set __file__ on frozen stdlib modules. (gh-28656) 

Currently frozen modules do not have __file__ set.  In their spec, origin is set to "frozen" and they are marked as not having a location.  (Similarly, for frozen packages __path__ is set to an empty list.)  However, for frozen stdlib modules we are able to extrapolate __file__ as long as we can determine the stdlib directory at runtime.  (We now do so since gh-28586.)  Having __file__ set is helpful for a number of reasons.  Likewise, having a non-empty __path__ means we can import submodules of a frozen package from the filesystem (e.g. we could partially freeze the encodings module).

This change sets __file__ (and adds to __path__) for frozen stdlib modules.  It uses sys._stdlibdir (from gh-28586) and the frozen module alias information (from gh-28655).  All that work is done in FrozenImporter (in Lib/importlib/_bootstrap.py). 
 Also, if a frozen module is imported before importlib is bootstrapped (during interpreter initialization) then we fix up that module and its spec during the importlib bootstrapping step (i.e. imporlib._bootstrap._setup()) to match what gets set by FrozenImporter, including setting the file info (if the stdlib dir is known).  To facilitate this, modules imported using PyImport_ImportFrozenModule() have __origname__ set using the frozen module alias info.  __origname__ is popped off during importlib bootstrap.

(To be clear, even with this change the new code to set __file__ during fixups in imporlib._bootstrap._setup() doesn't actually get triggered yet.  This is because sys._stdlibdir hasn't been set yet in interpreter initialization at the point importlib is bootstrapped.  However, we do fix up such modules at that point to otherwise match the result of importing through FrozenImporter, just not the __file__ and __path__ parts.  Doing so will require changes in the order in which things happen during interpreter initialization.  That can be addressed separately.  Once it is, the file-related fixup code from this PR will kick in.)

Here are things this change does not do:

* set __file__ for non-stdlib modules (no way of knowing the parent dir)
* set __file__ if the stdlib dir is not known (nor assume the expense of finding it)
* relatedly, set __file__ if the stdlib is in a zip file
* verify that the filename set to __file__ actually exists (too expensive)
* update __path__ for frozen packages that alias a non-package (since there is no package dir)

Other things this change skips, but we may do later:

* set __file__ on modules imported using PyImport_ImportFrozenModule()
* set co_filename when we unmarshal the frozen code object while importing the module (e.g. in FrozenImporter.exec_module()) -- this would allow tracebacks to show source lines
* implement FrozenImporter.get_filename() and FrozenImporter.get_source()

https://bugs.python.org/issue21736
This commit is contained in:
Eric Snow 2021-10-14 15:32:18 -06:00 committed by GitHub
parent b2af211e22
commit 79cf20e48d
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
7 changed files with 240 additions and 94 deletions
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177
Lib/importlib/_bootstrap.py
View File

@ -421,7 +421,10 @@ class ModuleSpec:
def spec_from_loader(name, loader, *, origin=None, is_package=None):
"""Return a module spec based on various loader methods."""
if hasattr(loader, 'get_filename'):
if origin is None:
origin = getattr(loader, '_ORIGIN', None)
if not origin and hasattr(loader, 'get_filename'):
if _bootstrap_external is None:
raise NotImplementedError
spec_from_file_location = _bootstrap_external.spec_from_file_location
@ -467,12 +470,9 @@ def _spec_from_module(module, loader=None, origin=None):
except AttributeError:
location = None
if origin is None:
if location is None:
try:
origin = loader._ORIGIN
except AttributeError:
origin = None
else:
if loader is not None:
origin = getattr(loader, '_ORIGIN', None)
if not origin and location is not None:
origin = location
try:
cached = module.__cached__
@ -484,7 +484,7 @@ def _spec_from_module(module, loader=None, origin=None):
submodule_search_locations = None
spec = ModuleSpec(name, loader, origin=origin)
spec._set_fileattr = False if location is None else True
spec._set_fileattr = False if location is None else (origin == location)
spec.cached = cached
spec.submodule_search_locations = submodule_search_locations
return spec
@ -541,6 +541,7 @@ def _init_module_attrs(spec, module, *, override=False):
# __path__
if override or getattr(module, '__path__', None) is None:
if spec.submodule_search_locations is not None:
# XXX We should extend __path__ if it's already a list.
try:
module.__path__ = spec.submodule_search_locations
except AttributeError:
@ -825,38 +826,127 @@ class FrozenImporter:
return '<module {!r} ({})>'.format(m.__name__, FrozenImporter._ORIGIN)
@classmethod
def _setup_module(cls, module):
assert not hasattr(module, '__file__'), module.__file__
ispkg = hasattr(module, '__path__')
assert not ispkg or not module.__path__, module.__path__
def _fix_up_module(cls, module):
spec = module.__spec__
assert not ispkg or not spec.submodule_search_locations
state = spec.loader_state
if state is None:
# The module is missing FrozenImporter-specific values.
if spec.loader_state is None:
spec.loader_state = type(sys.implementation)(
data=None,
origname=None,
)
elif not hasattr(spec.loader_state, 'data'):
spec.loader_state.data = None
if not getattr(spec.loader_state, 'origname', None):
# Fix up the spec attrs.
origname = vars(module).pop('__origname__', None)
assert origname, 'see PyImport_ImportFrozenModuleObject()'
spec.loader_state.origname = origname
ispkg = hasattr(module, '__path__')
assert _imp.is_frozen_package(module.__name__) == ispkg, ispkg
filename, pkgdir = cls._resolve_filename(origname, spec.name, ispkg)
spec.loader_state = type(sys.implementation)(
filename=filename,
origname=origname,
)
__path__ = spec.submodule_search_locations
if ispkg:
assert __path__ == [], __path__
if pkgdir:
spec.submodule_search_locations.insert(0, pkgdir)
else:
assert __path__ is None, __path__
# Fix up the module attrs (the bare minimum).
assert not hasattr(module, '__file__'), module.__file__
if filename:
try:
module.__file__ = filename
except AttributeError:
pass
if ispkg:
if module.__path__ != __path__:
assert module.__path__ == [], module.__path__
module.__path__.extend(__path__)
else:
# These checks ensure that _fix_up_module() is only called
# in the right places.
__path__ = spec.submodule_search_locations
ispkg = __path__ is not None
# Check the loader state.
assert sorted(vars(state)) == ['filename', 'origname'], state
if state.origname:
# The only frozen modules with "origname" set are stdlib modules.
(__file__, pkgdir,
) = cls._resolve_filename(state.origname, spec.name, ispkg)
assert state.filename == __file__, (state.filename, __file__)
if pkgdir:
assert __path__ == [pkgdir], (__path__, pkgdir)
else:
assert __path__ == ([] if ispkg else None), __path__
else:
__file__ = None
assert state.filename is None, state.filename
assert __path__ == ([] if ispkg else None), __path__
# Check the file attrs.
if __file__:
assert hasattr(module, '__file__')
assert module.__file__ == __file__, (module.__file__, __file__)
else:
assert not hasattr(module, '__file__'), module.__file__
if ispkg:
assert hasattr(module, '__path__')
assert module.__path__ == __path__, (module.__path__, __path__)
else:
assert not hasattr(module, '__path__'), module.__path__
assert not spec.has_location
@classmethod
def _resolve_filename(cls, fullname, alias=None, ispkg=False):
if not fullname or not getattr(sys, '_stdlib_dir', None):
return None, None
try:
sep = cls._SEP
except AttributeError:
sep = cls._SEP = '\\' if sys.platform == 'win32' else '/'
if fullname != alias:
if fullname.startswith('<'):
fullname = fullname[1:]
if not ispkg:
fullname = f'{fullname}.__init__'
else:
ispkg = False
relfile = fullname.replace('.', sep)
if ispkg:
pkgdir = f'{sys._stdlib_dir}{sep}{relfile}'
filename = f'{pkgdir}{sep}__init__.py'
else:
pkgdir = None
filename = f'{sys._stdlib_dir}{sep}{relfile}.py'
return filename, pkgdir
@classmethod
def find_spec(cls, fullname, path=None, target=None):
info = _call_with_frames_removed(_imp.find_frozen, fullname)
if info is None:
return None
data, ispkg, origname = info
# We get the marshaled data in exec_module() (the loader
# part of the importer), instead of here (the finder part).
# The loader is the usual place to get the data that will
# be loaded into the module. (For example, see _LoaderBasics
# in _bootstra_external.py.) Most importantly, this importer
# is simpler if we wait to get the data.
# However, getting as much data in the finder as possible
# to later load the module is okay, and sometimes important.
# (That's why ModuleSpec.loader_state exists.) This is
# especially true if it avoids throwing away expensive data
# the loader would otherwise duplicate later and can be done
# efficiently. In this case it isn't worth it.
_, ispkg, origname = info
spec = spec_from_loader(fullname, cls,
origin=cls._ORIGIN,
is_package=ispkg)
filename, pkgdir = cls._resolve_filename(origname, fullname, ispkg)
spec.loader_state = type(sys.implementation)(
data=data,
filename=filename,
origname=origname,
)
if pkgdir:
spec.submodule_search_locations.insert(0, pkgdir)
return spec
@classmethod
@ -873,26 +963,22 @@ class FrozenImporter:
@staticmethod
def create_module(spec):
"""Use default semantics for module creation."""
"""Set __file__, if able."""
module = _new_module(spec.name)
try:
filename = spec.loader_state.filename
except AttributeError:
pass
else:
if filename:
module.__file__ = filename
return module
@staticmethod
def exec_module(module):
spec = module.__spec__
name = spec.name
try:
data = spec.loader_state.data
except AttributeError:
if not _imp.is_frozen(name):
raise ImportError('{!r} is not a frozen module'.format(name),
name=name)
data = None
else:
# We clear the extra data we got from the finder, to save memory.
# Note that if this method is called again (e.g. by
# importlib.reload()) then _imp.get_frozen_object() will notice
# no data was provided and will look it up.
spec.loader_state.data = None
code = _call_with_frames_removed(_imp.get_frozen_object, name, data)
code = _call_with_frames_removed(_imp.get_frozen_object, name)
exec(code, module.__dict__)
@classmethod
@ -903,7 +989,16 @@ class FrozenImporter:
"""
# Warning about deprecation implemented in _load_module_shim().
return _load_module_shim(cls, fullname)
module = _load_module_shim(cls, fullname)
info = _imp.find_frozen(fullname)
assert info is not None
_, ispkg, origname = info
module.__origname__ = origname
vars(module).pop('__file__', None)
if ispkg:
module.__path__ = []
cls._fix_up_module(module)
return module
@classmethod
@_requires_frozen
@ -1244,7 +1339,7 @@ def _setup(sys_module, _imp_module):
spec = _spec_from_module(module, loader)
_init_module_attrs(spec, module)
if loader is FrozenImporter:
loader._setup_module(module)
loader._fix_up_module(module)
# Directly load built-in modules needed during bootstrap.
self_module = sys.modules[__name__]

3
Lib/test/test_frozen.py
View File

@ -39,9 +39,6 @@ class TestFrozen(unittest.TestCase):
self.assertIs(spam.__spec__.loader,
importlib.machinery.FrozenImporter)
# This is not possible until frozen packages have __path__ set properly.
# See https://bugs.python.org/issue21736.
@unittest.expectedFailure
def test_unfrozen_submodule_in_frozen_package(self):
with import_helper.CleanImport('__phello__', '__phello__.spam'):
with import_helper.frozen_modules(enabled=True):

29
Lib/test/test_importlib/frozen/test_finder.py
View File

@ -44,30 +44,31 @@ class FindSpecTests(abc.FinderTests):
if not filename:
if not origname:
origname = spec.name
filename = resolve_stdlib_file(origname)
actual = dict(vars(spec.loader_state))
# Check the code object used to import the frozen module.
# We can't compare the marshaled data directly because
# marshal.dumps() would mark "expected" (below) as a ref,
# which slightly changes the output.
# (See https://bugs.python.org/issue34093.)
data = actual.pop('data')
with import_helper.frozen_modules():
expected = _imp.get_frozen_object(spec.name)
code = marshal.loads(data)
self.assertEqual(code, expected)
# Check the rest of spec.loader_state.
expected = dict(
origname=origname,
filename=filename if origname else None,
)
self.assertDictEqual(actual, expected)
def check_search_locations(self, spec):
# Frozen packages do not have any path entries.
# (See https://bugs.python.org/issue21736.)
expected = []
"""This is only called when testing packages."""
missing = object()
filename = getattr(spec.loader_state, 'filename', missing)
origname = getattr(spec.loader_state, 'origname', None)
if not origname or filename is missing:
# We deal with this in check_loader_state().
return
if not filename:
expected = []
elif origname != spec.name and not origname.startswith('<'):
expected = []
else:
expected = [os.path.dirname(filename)]
self.assertListEqual(spec.submodule_search_locations, expected)
def test_module(self):

32
Lib/test/test_importlib/frozen/test_loader.py
View File

@ -3,10 +3,11 @@ from .. import util
machinery = util.import_importlib('importlib.machinery')
from test.support import captured_stdout, import_helper
from test.support import captured_stdout, import_helper, STDLIB_DIR
import _imp
import contextlib
import marshal
import os.path
import types
import unittest
import warnings
@ -30,20 +31,27 @@ def fresh(name, *, oldapi=False):
yield
def resolve_stdlib_file(name, ispkg=False):
assert name
if ispkg:
return os.path.join(STDLIB_DIR, *name.split('.'), '__init__.py')
else:
return os.path.join(STDLIB_DIR, *name.split('.')) + '.py'
class ExecModuleTests(abc.LoaderTests):
def exec_module(self, name, origname=None):
with import_helper.frozen_modules():
is_package = self.machinery.FrozenImporter.is_package(name)
code = _imp.get_frozen_object(name)
spec = self.machinery.ModuleSpec(
name,
self.machinery.FrozenImporter,
origin='frozen',
is_package=is_package,
loader_state=types.SimpleNamespace(
data=marshal.dumps(code),
origname=origname or name,
filename=resolve_stdlib_file(origname or name, is_package),
),
)
module = types.ModuleType(name)
@ -68,7 +76,6 @@ class ExecModuleTests(abc.LoaderTests):
self.assertEqual(getattr(module, attr), value)
self.assertEqual(output, 'Hello world!\n')
self.assertTrue(hasattr(module, '__spec__'))
self.assertIsNone(module.__spec__.loader_state.data)
self.assertEqual(module.__spec__.loader_state.origname, name)
def test_package(self):
@ -82,7 +89,6 @@ class ExecModuleTests(abc.LoaderTests):
name=name, attr=attr, given=attr_value,
expected=value))
self.assertEqual(output, 'Hello world!\n')
self.assertIsNone(module.__spec__.loader_state.data)
self.assertEqual(module.__spec__.loader_state.origname, name)
def test_lacking_parent(self):
@ -139,36 +145,41 @@ class LoaderTests(abc.LoaderTests):
def test_module(self):
module, stdout = self.load_module('__hello__')
filename = resolve_stdlib_file('__hello__')
check = {'__name__': '__hello__',
'__package__': '',
'__loader__': self.machinery.FrozenImporter,
'__file__': filename,
}
for attr, value in check.items():
self.assertEqual(getattr(module, attr), value)
self.assertEqual(getattr(module, attr, None), value)
self.assertEqual(stdout.getvalue(), 'Hello world!\n')
self.assertFalse(hasattr(module, '__file__'))
def test_package(self):
module, stdout = self.load_module('__phello__')
filename = resolve_stdlib_file('__phello__', ispkg=True)
pkgdir = os.path.dirname(filename)
check = {'__name__': '__phello__',
'__package__': '__phello__',
'__path__': [],
'__path__': [pkgdir],
'__loader__': self.machinery.FrozenImporter,
'__file__': filename,
}
for attr, value in check.items():
attr_value = getattr(module, attr)
attr_value = getattr(module, attr, None)
self.assertEqual(attr_value, value,
"for __phello__.%s, %r != %r" %
(attr, attr_value, value))
self.assertEqual(stdout.getvalue(), 'Hello world!\n')
self.assertFalse(hasattr(module, '__file__'))
def test_lacking_parent(self):
with util.uncache('__phello__'):
module, stdout = self.load_module('__phello__.spam')
filename = resolve_stdlib_file('__phello__.spam')
check = {'__name__': '__phello__.spam',
'__package__': '__phello__',
'__loader__': self.machinery.FrozenImporter,
'__file__': filename,
}
for attr, value in check.items():
attr_value = getattr(module, attr)
@ -176,7 +187,6 @@ class LoaderTests(abc.LoaderTests):
"for __phello__.spam.%s, %r != %r" %
(attr, attr_value, value))
self.assertEqual(stdout.getvalue(), 'Hello world!\n')
self.assertFalse(hasattr(module, '__file__'))
def test_module_reuse(self):
with fresh('__hello__', oldapi=True):

9
Misc/NEWS.d/next/Core and Builtins/2021-10-01-09-21-02.bpo-21736.RI47BU.rst Normal file
View File

@ -0,0 +1,9 @@
Frozen stdlib modules now have ``__file__`` to the .py file they would
otherwise be loaded from, if possible. For packages, ``__path__`` now has
the correct entry instead of being an empty list, which allows unfrozen
submodules to be imported. These are set only if the stdlib directory is
known when the runtime is initialized. Note that the file at ``__file__``
is not guaranteed to exist. None of this affects non-stdlib frozen modules
nor, for now, frozen modules imported using
``PyImport_ImportFrozenModule()``. Also, at the moment ``co_filename`` is
not updated for the module.

37
Python/clinic/import.c.h generated
View File

@ -170,7 +170,7 @@ exit:
}
PyDoc_STRVAR(_imp_find_frozen__doc__,
"find_frozen($module, name, /)\n"
"find_frozen($module, name, /, *, withdata=False)\n"
"--\n"
"\n"
"Return info about the corresponding frozen module (if there is one) or None.\n"
@ -184,26 +184,43 @@ PyDoc_STRVAR(_imp_find_frozen__doc__,
" the module\'s current name)");
#define _IMP_FIND_FROZEN_METHODDEF \
{"find_frozen", (PyCFunction)_imp_find_frozen, METH_O, _imp_find_frozen__doc__},
{"find_frozen", (PyCFunction)(void(*)(void))_imp_find_frozen, METH_FASTCALL|METH_KEYWORDS, _imp_find_frozen__doc__},
static PyObject *
_imp_find_frozen_impl(PyObject *module, PyObject *name);
_imp_find_frozen_impl(PyObject *module, PyObject *name, int withdata);
static PyObject *
_imp_find_frozen(PyObject *module, PyObject *arg)
_imp_find_frozen(PyObject *module, PyObject *const *args, Py_ssize_t nargs, PyObject *kwnames)
{
PyObject *return_value = NULL;
static const char * const _keywords[] = {"", "withdata", NULL};
static _PyArg_Parser _parser = {NULL, _keywords, "find_frozen", 0};
PyObject *argsbuf[2];
Py_ssize_t noptargs = nargs + (kwnames ? PyTuple_GET_SIZE(kwnames) : 0) - 1;
PyObject *name;
int withdata = 0;
if (!PyUnicode_Check(arg)) {
_PyArg_BadArgument("find_frozen", "argument", "str", arg);
args = _PyArg_UnpackKeywords(args, nargs, NULL, kwnames, &_parser, 1, 1, 0, argsbuf);
if (!args) {
goto exit;
}
if (PyUnicode_READY(arg) == -1) {
if (!PyUnicode_Check(args[0])) {
_PyArg_BadArgument("find_frozen", "argument 1", "str", args[0]);
goto exit;
}
name = arg;
return_value = _imp_find_frozen_impl(module, name);
if (PyUnicode_READY(args[0]) == -1) {
goto exit;
}
name = args[0];
if (!noptargs) {
goto skip_optional_kwonly;
}
withdata = PyObject_IsTrue(args[1]);
if (withdata < 0) {
goto exit;
}
skip_optional_kwonly:
return_value = _imp_find_frozen_impl(module, name, withdata);
exit:
return return_value;
@ -548,4 +565,4 @@ exit:
#ifndef _IMP_EXEC_DYNAMIC_METHODDEF
#define _IMP_EXEC_DYNAMIC_METHODDEF
#endif /* !defined(_IMP_EXEC_DYNAMIC_METHODDEF) */
/*[clinic end generated code: output=8c8dd08158f9ac7c input=a9049054013a1b77]*/
/*[clinic end generated code: output=adcf787969a11353 input=a9049054013a1b77]*/

47
Python/import.c
View File

@ -2049,6 +2049,8 @@ _imp.find_frozen
name: unicode
/
*
withdata: bool = False
Return info about the corresponding frozen module (if there is one) or None.
@ -2062,8 +2064,8 @@ The returned info (a 2-tuple):
[clinic start generated code]*/
static PyObject *
_imp_find_frozen_impl(PyObject *module, PyObject *name)
/*[clinic end generated code: output=3fd17da90d417e4e input=6aa7b9078a89280a]*/
_imp_find_frozen_impl(PyObject *module, PyObject *name, int withdata)
/*[clinic end generated code: output=8c1c3c7f925397a5 input=22a8847c201542fd]*/
{
struct frozen_info info;
frozen_status status = find_frozen(name, &info);
@ -2078,9 +2080,12 @@ _imp_find_frozen_impl(PyObject *module, PyObject *name)
return NULL;
}
PyObject *data = PyBytes_FromStringAndSize(info.data, info.size);
if (data == NULL) {
return NULL;
PyObject *data = NULL;
if (withdata) {
data = PyMemoryView_FromMemory((char *)info.data, info.size, PyBUF_READ);
if (data == NULL) {
return NULL;
}
}
PyObject *origname = NULL;
@ -2092,11 +2097,11 @@ _imp_find_frozen_impl(PyObject *module, PyObject *name)
}
}
PyObject *result = PyTuple_Pack(3, data,
PyObject *result = PyTuple_Pack(3, data ? data : Py_None,
info.is_package ? Py_True : Py_False,
origname ? origname : Py_None);
Py_XDECREF(origname);
Py_DECREF(data);
Py_XDECREF(data);
return result;
}
@ -2115,15 +2120,14 @@ _imp_get_frozen_object_impl(PyObject *module, PyObject *name,
PyObject *dataobj)
/*[clinic end generated code: output=54368a673a35e745 input=034bdb88f6460b7b]*/
{
struct frozen_info info;
if (PyBytes_Check(dataobj)) {
info.nameobj = name;
info.data = PyBytes_AS_STRING(dataobj);
info.size = PyBytes_Size(dataobj);
if (info.size == 0) {
set_frozen_error(FROZEN_INVALID, name);
struct frozen_info info = {0};
Py_buffer buf = {0};
if (PyObject_CheckBuffer(dataobj)) {
if (PyObject_GetBuffer(dataobj, &buf, PyBUF_READ) != 0) {
return NULL;
}
info.data = (const char *)buf.buf;
info.size = buf.len;
}
else if (dataobj != Py_None) {
_PyArg_BadArgument("get_frozen_object", "argument 2", "bytes", dataobj);
@ -2136,7 +2140,20 @@ _imp_get_frozen_object_impl(PyObject *module, PyObject *name,
return NULL;
}
}
return unmarshal_frozen_code(&info);
if (info.nameobj == NULL) {
info.nameobj = name;
}
if (info.size == 0) {
set_frozen_error(FROZEN_INVALID, name);
return NULL;
}
PyObject *codeobj = unmarshal_frozen_code(&info);
if (dataobj != Py_None) {
PyBuffer_Release(&buf);
}
return codeobj;
}
/*[clinic input]