IDLE: warn if save-as name matches stdlib name

[terryjreedy]

BPO	25522
Nosy	@terryjreedy, @roseman, @vedgar, @ZackerySpytz
PRs	python/cpython#17051

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

Show more details

GitHub fields: ```python assignee = 'https://github.com/terryjreedy' closed_at = None created_at = labels = ['expert-IDLE', 'type-feature', '3.7'] title = 'IDLE: warn if save-as name matches stdlib name' updated_at = user = 'https://github.com/terryjreedy' ``` bugs.python.org fields: ```python activity = actor = 'ZackerySpytz' assignee = 'terry.reedy' closed = False closed_date = None closer = None components = ['IDLE'] creation = creator = 'terry.reedy' dependencies = [] files = [] hgrepos = [] issue_num = 25522 keywords = ['patch'] message_count = 8.0 messages = ['253775', '253777', '253829', '253830', '333944', '333952', '334279', '355988'] nosy_count = 6.0 nosy_names = ['terry.reedy', 'markroseman', 'THRlWiTi', 'veky', 'lac', 'ZackerySpytz'] pr_nums = ['17051'] priority = 'normal' resolution = None stage = 'patch review' status = 'open' superseder = None type = 'enhancement' url = 'https://bugs.python.org/issue25522' versions = ['Python 3.6', 'Python 3.7'] ```

[terryjreedy]

When users 'saveas', warn if name matches that of a stdlib modules. Note that shadowing is opposite for lib and binary (builtin) modules, so message needs to be different. I am not worrying about 3rd party modules on the search path (ie, site-packages), which would be shadowed like lib modules. Rough outline of code to add to IOBinding.

from os,path import dirname import sys

# this part on initiallzation or first saveas call
def libmodules():
    with open(dirname(dirname(__file__))) as lib:
        for f in lib:
            if <directory containing __init__.py#> or f.endswith(.py):
                yield f
# test.test__all__ has this code

islibmodule = frozenset(libmodules()).__contains__
isbinmodule = frozenset(sys.builtin_module_names).__contains__

# this part after saveas dialog returns
if islibmodule(name):
    go = warn("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?".)
elif isbinmodule(name):
    go = warn("This name matches a builtin stdlib name.  You will not be able to import this file.  Continue?".)
else:
    go = True
if go:
    <save as requested>
else:
   (get name again>  # or put in while not go loop

[terryjreedy]

The lib messages should say "Neither you nor python will be able to import the stdlib module". Example of python-imported lib names that a beginner might write are abc, io, os, nt, and stat.

[2fa77a64-b4c3-4691-9044-696c49d370ff]

I'm not sure about "Neither you nor Python will be able to import the stdlib." Depending on what the file is, you may be able to import it later. I'd prefer:

"If you run Python in this directory, your version of \<stdlibname> will be used instead of the one in the standard library. This may cause Idle to behave strangely, or possibly not run at all."

[2fa77a64-b4c3-4691-9044-696c49d370ff]

Do we need a full path name here as well? Probably not.

[terryjreedy]

Also check if the name is not an identifier and therefore could not be imported. Example:

>>> exec('import abc--bb')
    import abc--bb
              ^
SyntaxError: invalid syntax

[fe5a23f9-4d47-49f8-9fb5-d6fbad5d9e38]

Many beginners don't write files in order to import them. For them, these name-checking is simply adding noise. If you want to do something in this area, I think a much more useful (and difficult) course of action would be to check on the opposite end. If an AttributeError "module blah has no attribute foo" is raised, then check whether a file in the current directory (or simply the current file) is named blah, and there is also a stdlib blah that has fool.

[terryjreedy]

Beginners import stdlib files such as random. And they save scripts with such name, and accidentally import the script when not desired.

Beginners should learn how to test a script by running a test file provided by an instructor or written themselves. In either case, they *will* have to import the script.

[2776f601-9573-4690-ab86-59139fdf3c89]

I have created a pull request for this issue.