[Python-Dev] If you shadow a module in the standard library that IDLE depends on, bad things happen

[Ryan Gonzalez]

Well, this works on Python 2 only (I'm on a phone with only access to 2 right now), but this is a start (apologies for the screwy syntax highlighting):
	
import sys, imp, logging, os

modules = '''
imp
string
...
'''.split()

class StdlibTester(object):
    base = os.path.dirname(os.__file__) # hack; is there a better way to do this?

    def find_module(self, fullname, path=None):
        if fullname in modules:
            self.path = path
            return self
        return None

    def load_module(self, name):
        if name in sys.modules:
            return sys.modules[name]
        module_info = imp.find_module(name, self.path)
        module = imp.load_module(name, *module_info)
        sys.modules[name] = module

        if hasattr(module, '__file__') and not os.path.dirname(module.__file__).startswith(self.base):
            logging.warning('stdlib module %s was overriden', name)

        return module

sys.meta_path.append(StdlibTester())
import string


On October 29, 2015 7:06:51 PM CDT, "R. David Murray" <rdmurray at bitdance.com> wrote:
>On Thu, 29 Oct 2015 16:56:38 -0700, Nathaniel Smith <njs at pobox.com>
>wrote:
>> On Thu, Oct 29, 2015 at 1:50 PM, Ryan Gonzalez <rymg19 at gmail.com>
>wrote:
>> > Why not just check the path of the imported modules and compare it
>with the
>> > Python library directory?
>> 
>> It works, but it requires that everyone who could run into this
>> problem carefully add some extra guard code to every stdlib import
>> statement, and in practice nobody will (or at least, not until after
>> they've already gotten bitten by this at least once... at which point
>> they no longer need it).
>> 
>> Given that AFAICT there's no reason this couldn't be part of the
>> default import system's functionality and "just work" for everyone,
>if
>> I were going to spend time on trying to fix this I'd probably target
>> that :-).
>> 
>> (I guess the trickiest bit would be to find an efficient and
>> maintainable way to check whether a given package name is present in
>> the stdlib.)
>
>For Idle, though, it sounds like a very viable strategy, and that's
>what Laura is concerned about.
>
>--David
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-- 
Sent from my Nexus 5 with K-9 Mail. Please excuse my brevity.
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