When file_use_mail_timestamp or utime_from_header are enabled,
OfflineIMAP tries to parse the Date header in the email. If the header
is present but invalid -- it doesn't contain a valid date -- this will
cause email.message to raise an exception. This is all fine. However
when handling that exception, OfflineIMAP can't try to extract the date
again: it's clearly invalid, and raising the same exception a second
time while handling the first exception just causes the entire sync to
fail.
To avoid that happening, don't try to provide the invalid date string in
the error message. Instead, just give the user the UID of the email
that triggered the exception, and the exception text.
Ideally we'd instead fix the code to actually extract the header value
and provide it in the error message, but Python's email.message module
doesn't provide an easy way to get the raw text of the Date header from
an EmailMessage object; it's possible using private variables like
EmailMessage._headers, or by parsing the email using a custom
email.policy.EmailPolicy object that disables the module's attempts to
coerce the header value to a DateTime. However, a user should be able
to get the problematic Date header from the message directly anyway, so
it's not worth adding all that complexity for something that should be
rare and provides little value.
Fixes#134
Signed-off-by: Adam Dinwoodie <adam@dinwoodie.org>
416df5d7c2