On Mon, Jan 25, 2021 at 7:51 AM Ivan Pozdeev via Python-Dev < python-dev@python.org> wrote:
> Just _names_? There's a recurring error case when a 3rd-party module > overrides a standard one if it happens to have the same name. If you > filter such a module out, you're shooting yourself in the foot... Would another use case be to support issuing a warning if a third-party module is imported whose name matches a standard one? A related use case would be to build on this and define a function that accepts an already imported module and return whether it is from the standard library. Unlike, the module_names attribute, this function would reflect the reality of the underlying module, and so not have false positives as with doing a name check alone. —Chris > > On 25.01.2021 16:03, Victor Stinner wrote: > > Hi, > > > > I just added a new sys.module_names attribute, list (technically a > > frozenset) of all stdlib module names: > > https://bugs.python.org/issue42955 > > > > There are multiple use cases: > > > > * Group stdlib imports when reformatting a Python file, > > * Exclude stdlib imports when computing dependencies. > > * Exclude stdlib modules when listing extension modules on crash or > > fatal error, only list 3rd party extension (already implemented in > > master, see bpo-42923 ;-)). > > * Exclude stdlib modules when tracing the execution of a program using > > the trace module. > > * Detect typo and suggest a fix: ImportError("No module named maths. > > Did you mean 'math'?",) (test the nice friendly-traceback project!). > > > > Example: > > > >>>> 'asyncio' in sys.module_names > > True > >>>> 'numpy' in sys.module_names > > False > > > >>>> len(sys.module_names) > > 312 > >>>> type(sys.module_names) > > <class 'frozenset'> > > > >>>> sorted(sys.module_names)[:10] > > ['__future__', '_abc', '_aix_support', '_ast', '_asyncio', '_bisect', > > '_blake2', '_bootsubprocess', '_bz2', '_codecs'] > >>>> sorted(sys.module_names)[-10:] > > ['xml.dom', 'xml.etree', 'xml.parsers', 'xml.sax', 'xmlrpc', 'zipapp', > > 'zipfile', 'zipimport', 'zlib', 'zoneinfo'] > > > > The list is opinionated and defined by its documentation: > > > > A frozenset of strings containing the names of standard library > > modules. > > > > It is the same on all platforms. Modules which are not available on > > some platforms and modules disabled at Python build are also listed. > > All module kinds are listed: pure Python, built-in, frozen and > > extension modules. Test modules are excluded. > > > > For packages, only sub-packages are listed, not sub-modules. For > > example, ``concurrent`` package and ``concurrent.futures`` > > sub-package are listed, but not ``concurrent.futures.base`` > > sub-module. > > > > See also the :attr:`sys.builtin_module_names` list. > > > > The design (especially, the fact of having the same list on all > > platforms) comes from the use cases list above. For example, running > > isort should produce the same output on any platform, and not depend > > if the Python stdlib was splitted into multiple packages on Linux > > (which is done by most popular Linux distributions). > > > > The list is generated by the Tools/scripts/generate_module_names.py > script: > > > https://github.com/python/cpython/blob/master/Tools/scripts/generate_module_names.py > > > > When you add a new module, you must run "make regen-module-names, > > otherwise a pre-commit check will fail on your PR ;-) The list of > > Windows extensions is currently hardcoded in the script (contributions > > are welcomed to discover them, since the list is short and evolves > > rarely, I didn't feel the need to spend time that on that). > > > > Currently (Python 3.10.0a4+), there are 312 names in sys.module_names, > > stored in Python/module_names.h: > > https://github.com/python/cpython/blob/master/Python/module_names.h > > > > It was decided to include "helper" modules like "_aix_support" which > > is used by sysconfig. But test modules like _testcapi are excluded to > > make the list shorter (it's rare to run the CPython test suite outside > > Python). > > > > There are 83 private modules, name starting with an underscore > > (exclude _abc but also __future__): > > > >>>> len([name for name in sys.module_names if not name.startswith('_')]) > > 229 > > > > This new attribute may help to define "what is the Python stdlib" ;-) > > > > Victor > > -- > Regards, > Ivan > _______________________________________________ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/KCJDHKOKCN5343VVA3DC7RAGNUGWNKZY/ > Code of Conduct: http://python.org/psf/codeofconduct/ >
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