If a ParsingError occurs while reading a config file, the multi-line values collected while reading will never be joined because the error is raised before this can happen. This leads to very unexpected results, e.g. consider the following config.ini:

[DEFAULT]
test = test
invalid

>>> cfg = ConfigParser.ConfigParser()
>>> cfg.read(['config.ini'])

This will raise a ParsingError as expected. But the option values that were parsed without error are now all lists instead of strings:

>>> cfg.get('DEFAULT', test')
['test']

Patch attached.