Implement hasattr_warn(); run to remove hasattr(prop) calls

[trevorbaca]

We've experienced too many relatively significant bugs related to calling hasattr() on properties.

We need a way to audit the entire codebase and remove all cases of calling hasattr() on properties.

How to do this?

We don't need anything superelegant. Just something that will let us run over the codebase and go manually fix everything found.

One solution would be to implement a custom hasattr_warn() function. The function would raise an exception in the case that it's input argument is a property. Probably define directly in the abjad/__init__.py module so that we can then add the function to the __builtins__ namespace with something like __builtins__['hasattr_warn'] = hasattr_warn. Then we could globally search and replace all hasattr() with hasattr_warn() and then run and fix the tests iteratively until everything runs and no more exceptions are raised. Then globally search and replace to change all hasattr_warn() calls back to vanilla hasattr().

[trevorbaca]

Still valid in June 2017.

[trevorbaca]

A hasattr_warn() replacement now exists in the Abjad __init__.py file. Just uncomment and run the tests to see what fails.

Current doctests:

12492 passed, 2654 failed out of 15146 tests in 821 modules.

Current pytests:

813 failed, 9349 passed, 523 skipped in 226.93 seconds

[trevorbaca]

Current doctests:

14890 passed, 256 failed out of 15146 tests in 821 modules.

Current pytests:

81 failed, 10081 passed, 523 skipped in 198.14 seconds

[trevorbaca]

Done in 2.21.

The following remains in the Abjad __init__.py for future housecleaning:

def hasattr_warn(argument, name, original_hasattr=hasattr):
    if original_hasattr(argument.__class__, name):
        value = getattr(argument.__class__, name)
        if isinstance(value, property):
            message = 'WARNING: {}.{} is a property!'
            message = message.format(argument.__class__.__name__, name)
            raise Exception(message)
    return original_hasattr(argument, name)
__builtins__['hasattr'] = hasattr_warn