ProcessorFormatter doesn't handle librarys which send dicts to standard logger well

[wrouesnel]

The processor formatter uses this line to distinguish between Structlog and regular messages:

if isinstance(record.msg, dict):

Unfortunately this runs afoul of any library or bug which happens to accidentally pass a dict object to the Python standard library logger (in the wild I've found the connexion library does this in some of its initialization code, producing exceptions when using structlog). This happens because the record entry doesn't have _logger attached because it didn't come through structlog.

IMO the ideal solution would be for the wrap_for_formatter handler to actually supply a wrapped dictionary type which could be tested for directly, but this doesn't seem particularly viable.

The best solution therefore is probably to embrace duck-typing in this code path and change the check to ensure the expected attributes are actually there:

if isinstance(record.msg, dict) and hasattr(record, "_logger") and hasattr(record,"_name"):

[hynek]

Fixed by #189