gh-121604: Raise DeprecationWarnings in importlib

[rashansmith]

This fixes #121604.

• 
 importlib.abc.ResourceLoader
• 
 importlib.abc.SourceLoader.path_mtime()
• 
 importlib.machinery.DEBUG_BYTECODE_SUFFIXES
• 
 importlib.machinery.OPTIMIZED_BYTECODE_SUFFIXES
• 
 importlib.machinery.WindowsRegistryFinder
• importlib.machinery.SourcelessFileLoader

The others defined in the issue can be considered already done.

Issue: #121604

• Issue: Make sure all deprecated items in importlib raise DeprecationWarning #121604

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[tomasr8]

Thanks! I left you some comments ;)

[tomasr8]

I'd keep the newline

[rashansmith]

@tomasr8 thanks for the review, I made some changes.

[tomasr8]

I'm not 100% sure but I think we should raise the deprecation warning when the class is imported, not when you create a new instance with it. Going by the example in the original PEP 562 it'd look (I think) something like this:

# Rename the deprecated class
class _Loader(metaclass=abc.ABCMeta):
    ...

def __getattr__(name):
    if name == 'Loader':
        warnings.warn(f"The 'Loader' class is deprecated.",
                      DeprecationWarning, stacklevel=2)
        return _Loader
    raise AttributeError(f"module {__name__!r} has no attribute {name!r}")

[rashansmith]

Ok, no problem. Thanks for the reference link! Another approach I had was to just put the warning message by itself in the first line under the class name. Would this have a similar affect? I removed it because I then saw the deprecation error when running the make command.

[tomasr8]

I think the problem with the other approach is that you'll get the warning whenever you import the module, not just the deprecated class specifically. For example, import importlib.abc will produce a warning for InspectLoader even if you're not actually using it

[CharlieZhao95]

The first if statement could be omitted, just use the if-elif statement ;)

if name in ('DEBUG_BYTECODE_SUFFIXES', 'OPTIMIZED_BYTECODE_SUFFIXES'):
    ...
elif name == 'WindowsRegistryFinder':
    ...

[brettcannon]

FYI this PR breaks the test suite, so CI isn't passing.

[tomasr8]

Hi @rashansmith! Looks like this PR hasn't had any activity in a while, would you like to continue working on it?

[StanFromIreland]

Hello @rashansmith if you do not have the time to complete this I can take on the project.

[tomasr8]

Hello @rashansmith if you do not have the time to complete this I can take on the project.

Hey! Thanks for volunteering @StanFromIreland, but I'm already working on finishing this PR :/ If you still want to help with this though, I'd appreciate your review! I'll send the updated PR tomorrow 🙂

[tungol]

This MR is currently adding deprecation warnings to importlib.abc.Loader, importlib.machinery.SourcelessFileLoader, and importlib.abc.InspectLoader, but none of those are currently documented as being deprecated; just the load_module method for each.

[rashansmith]

Hello everyone, thanks for taking this on. It was my first attempt at a PR in this repo so I'm looking forward to seeing how the work here is done and hopefully I can contribute to more work in the future!

[tomasr8]

Thanks @rashansmith for your work! I'm giving you credit in the followup PR :)

I'll close this now since it's superseded by #128007