Hi,

This is something that has hit us a few times, as we write a significant quantity of software which parses email messages.

The thing is, we use email.header.decode_header to decode the Subject: header and it is pretty common for headers to be word-wrapped. If they are, decode_header will return a string with newlines in it.

This is something which is unexpected for many people, and can cause bugs which are very difficult to detect in code review or testing, as it's easy to not trigger wordwrapping if not done deliberately.

We would humbly suggest to provide a friendly way to get an email's subject in the expected fashion (i.e. with no newlines) or point out this caveat in the docs (or maybe change decode_header to remove newlines itself).

Kind regards,

Álex