commit dc68e97937bf589b31bde1b083c6530c94ec14b4
author Thomas Gleixner <tglx@linutronix.de> Fri Jun 09 23:17:26 2023 +0200
committer Thomas Gleixner <tglx@linutronix.de> Tue Jun 20 23:43:23 2023 +0200
tree 55d6157dac314b2142ef4bfc1c494e7bf8b3f45d
parent 424944ad36e9925a9d3856b7054ca7fcc26f1ea6

remail: Make From header mangling less convoluted

Due to the requirement to reencrypt the incoming mail, remail must rewrite
the mail headers and create a new email with the 'From:' header being the
list address. So remail implemented a scheme to mangle the original senders
name into the reencrypted mails 'From:' header.

That fell flat on its nose when there was an incoming mail which had no
name part and just consisted of the actual email address. Instead of
differentiating between these cases the authors sleep deprived and grump
laden brain decided to implement 'From:' mangling in the way it is now.

It converts the original sender mail address '[Name]
<mailname@sender.domain>' to:

  'list-name for mailname_at_sender.domain' <list-name@list.domain>

This is hard to read and follow. 

Use the common format:

  'Name via list-name' <list-name@list.domain>

Except for the case where the original 'From:' header is a plain email
address without a name. This will mangle it to:

  'mailname at sender.domain via list-name' <list-name@list.domain>

The 'via list-name' add on is technically not required but is useful to
visually differentiate the name in auto-completion.

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>