Bug#1126508: dpkg's email validation module does not check for "." in the domain

Hi!

On Wed, 2026-01-28 at 00:30:21 +0530, Nilesh Patra wrote:
> Package: dpkg
> Severity: normal
> X-Debbugs-Cc: [email protected]
> Control: affects -1 + src:lintian
> Version: 1.23.5

> While trying to fix tests for lintian, I noticed that specifying the
> email as "username@localhost" in Uploaders field does not cause the
> build to choke.
> 
> That means that dpkg is accepting malformed address here, as it should
> check also if TLD is present or not.

While implementing the parser/validator I wondered whether I should
enforce this, and because I was unsure, I left it as is (at least for
now), as we can always enforce it later (given that there was no
enforcing before).

I guess my worry would be whether that would break any existing valid
use (outside of the Debian archive) for locally/internal/vendor built
packages, and for the myriad of brand TLDs (for example), although for
the latter I think I've read somewhere that TLDs are not supposed to
have MXs defined?

Thanks,
Guillem