IDLE/pyclbr failures for __main__

[terryjreedy]

Bug report

This discuss post says that IDLE's module browser, which uses pyclrb, fails if the file name is __main__, the filename has a '.', or the file has a syntax error. The first is the fault of of importlib.util._find_spec_from_path('main') failing (##117742). I need to verify the second. The third is a result of switching from custom parsing code that passed over syntax errors to ast.parse which does not -- and not noticing the possibility of exceptions and taking them into account. Since IDLE seems to hang, it is not clear where, and whether IDLE gets the exception.

[FFY00]

Isn't the __main__ conflict an inherent limitation of the module browser feature of IDLE, given that from what I can tell it is designed to work on loaded modules? How is this different from trying to work on two modules with the same name but in different locations in sys.path, for example? I think the only difference here is that __main__ is a module that always exists.

Regarding the issues with filenames containing ., similarly, we are operating at the module level, not the filesystem, and files with . in the name are not valid modules using the standard loaders. How is this different from filenames containing -?

Perhaps I am missing something here, if so please let me know, I am not a big user of IDLE.