APPEND command error: BAD ['invalid rfc5322 message: Sender should not be present if equal to From'] about offlineimap3 HOT 3 CLOSED

Hi @majorminors

Thanks a lot for the report. I tried to send me an email to protonmail using mutt, setting the sender the from with the same string and protonmail removes the "Sender" line. I tryid to add the sender with double quotes, and the same.

How can I reproduce the error? Should we implement a method to remove the sender line if is equal to the From line (with or without double quotes)?

Best regards,
kix

from offlineimap3.

Interesting! I hadn't been back to check this issue in a while, and I'm realising it's because I haven't encountered the problem in a while (previously at was at least once every couple days). Either someone (proton?) Have fixed the issue on their end, or I'm unconsciously screening the mails I know are a problem. Let me wait until a known problem sender hits my inbox and ill see if it still happens.

As for the solution you mention---automatically removing the sender---seems sensible to me given the RFC formatting recommendation in the error. But also I'd just be trusting proton that this is correct email formatting.

from offlineimap3.

So, I just deleted an email from the same source as the one that I used to illustrate this issue (Palm report), and offlineimap managed it with no issues.

Interestingly, unlike your attempt, protonmail doesn't appear to have stripped the 'Sender' field---they're still the same:

From: PALM REPORT by Poolsuite [email protected]
Sender: PALM REPORT by Poolsuite [email protected]

Although I note the double quotes are gone from the 'From' field. Not sure if that's important.

Anyway, I guess I'll close the issue, since it's solved for me somehow. If you want to re-open it for testing, feel free, and I'll be happy respond as I can to help out.

I'll also mention that it was resolved on my issue on the old offlineimap repo.

from offlineimap3.