do not drop bug emails from signed but not registered addresses

[sds]

A legitimate bug e-mail response is __silently dropped__ if it comes from an unknown e-mail address.
The correct behavior is to _bounce it back_ to the DKIM sender
with a request to create an account or
add the e-mail to an existing account
(with explicit URLs of pages for those actions).

Related to https://bugs.launchpad.net/launchpad/+bug/925597

[Robert Collins (lifeless)]

This isn't a regression (because we dropped such mails more or less always), but it would be very nice to have.

[Adam Porter (alphapapa)]

This is a regression, in that what used to work suddenly doesn't work. I have been using Launchpad since it began. Suddenly, a few weeks ago, I noticed my emailed bug comments were never appearing on Launchpad. I haven't changed anything. Maybe Gmail has. But Gmail ADDING support for a feature in the headers shouldn't cause my emails to DISAPPEAR with no explanation.

To summarize: Emails that used to go through now vanish without explanation. How is this not a CRITICAL BUG? The only thing that would make this bug MORE critical is if it were a security hole. How many thousands of people using Gmail aren't even aware that their comments have been going into the giant bit bucket in the sky? Where are Launchpad's priorities?

[sds (sds-gnu)]

I agree with Adam. This is an unmitigated disaster.
In a way, this is worse than a security hole because an unexploited security hole is just a potential loss,
while thousands of comments going to /dev/null is an actual loss of information which may create conflicts between users (waiting for a fix) and developers (waiting for feedback which you suddenly sent to /dev/null).

a link to this bug should be on EVERY launchpad page right NOW in huge bold red letters telling people that their mail has been discarded and IS BEING DISCARDED right now..

[Robert Collins (lifeless)]

The linked bug 925597 *is* marked critical, and is indeed a regression. Once fixed your mails will go through to the bug as they were before

Discarding mail from unknown senders is and will remain LP policy - see the prior discussions. Enhancing our DKIM support to send an NDR *now* that we can know who to send it to without being a spam backscatter source is an *enhancement* not a regression.