[Python-ideas] Add 'module' module, similar to 'keyword' module

[Brett Cannon]

On Sat, 31 Oct 2015 at 11:33 Steve Dower <steve.dower at python.org> wrote:

> Could we add a context manager to importlib (or perhaps site or sys) to
> temporarily disable imports from non-standard paths? I don't see any safe
> way to change the default behavior, but no reason we can't make it easy for
> applications to self-isolate.
>

There's https://www.python.org/dev/peps/pep-0406/ which tried to get
isolated import data. As for an immediate solution, trick is whether we
have stored somewhere what  the standard path entries are or if we have a
reliable way to figure out which paths are standard or not. There is also
the problem of not being thread-safe when swapping out sys.path entries.

-Brett


>
> Top-posted from my Windows Phone
> ------------------------------
> From: Brett Cannon <brett at python.org>
> Sent: ‎10/‎31/‎2015 9:50
> To: Terry Reedy <tjreedy at udel.edu>; python-ideas at python.org
> Subject: Re: [Python-ideas] Add 'module' module, similar to 'keyword'
> module
>
>
>
> On Fri, 30 Oct 2015 at 22:57 Terry Reedy <tjreedy at udel.edu> wrote:
>
>> On 10/30/2015 9:19 PM, Guido van Rossum wrote:
>> > There's sys.builtin_module_names which returns the names of the
>> > hardcoded builtin modules.
>>
>> Great.  With this solved, I opened an issue for IDLE.
>> https://bugs.python.org/issue25522
>>
>> > Dynamically loaded modules can be found by
>> > searching sys.path in the usual way -- importlib shoul know. I wonder if
>> > just asking importlib whether it can locate a given module would be
>> enough?
>>
>> The default search order is stdlib builtins, local user files, /lib
>> files, so the shadowing issue the opposite for builtin and /lib modules.
>>   Hence a different message is needed.
>>
>
> Quick and dirty way to use importlib is to get the location of the stdlib
> (os.__file__ should work since it's hard-coded in the interpreter as
> representing where the stdlib is) and then use importlib.find_spec() for a
> module name to check if the file location in the spec has the same location
> prefix as os or not (make sure you use absolute paths since it isn't
> guaranteed if you don't execute site.py).
>
> I've now seen this use case, the logging one, and the 2to3 module rename.
> I'm starting to wonder if there some general solution that should get added
> to the import machinery that  can serve these cases more easily than with
> importers or __import__ overrides that can be tricky to get right.
>
> -Brett
>
>
>>
>> > On Fri, Oct 30, 2015 at 6:09 PM, Terry Reedy
>> > <tjreedy at udel.edu
>> > <mailto:tjreedy at udel.edu>> wrote:
>> >
>> >     This idea results from issue of user files shadowing stdlib files on
>> >     import.  There was a thread on pydev about this yesterday.  There is
>> >     also an opposite issue of builtin modules shadowing user files.
>> >
>> >     The keyword module provides kwlist and iskeyword function.  One use
>> >     of kwlist is used in some other stdlib modules and can be used by
>> >     syntax highlighters (as in IDLE).  Kwlist is updated by the main
>> >     function.
>> >
>> >     A module module would have at least liblist and islibmodule
>> >     function. Liblist would contain all directories with __init__.py and
>> >     all .py files.  (I don't think files within package directories
>> >     should be included, as there is no direct shadowing problem.)  A
>> >     python oriented editor could then warn on save requests "This name
>> >     matches a stdlib name in /Lib. If you run python in this directory,
>> >     you will not be able to import the stdlib module.  Continue?".
>> >
>> >     The module should also have binlist and isbinmodule for builtin
>> >     modules.  (I do not know how to get such a list.  If necessary, an
>> >     api could be added.)  An editor could than warn "This name matches a
>> >     builtin stdlib name.  You will not be able to import this file.
>> >     Continue?".
>> >
>> >     --
>> >     Terry Jan Reedy
>> >
>> >     _______________________________________________
>> >     Python-ideas mailing list
>> >     Python-ideas at python.org
>> >     <mailto:Python-ideas at python.org>
>> >     https://mail.python.org/mailman/listinfo/python-ideas
>> >     Code of Conduct: http://python.org/psf/codeofconduct/
>> >
>> >
>> >
>> >
>> > --
>> > --Guido van Rossum (python.org/~guido <http://python.org/~guido>)
>> >
>> >
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>> >
>>
>>
>> --
>> Terry Jan Reedy
>>
>> _______________________________________________
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>>
>
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