bug#66602: 29.1; smtpmail-send-it fails to authenticate using auth-sources

[Eli Zaretskii <eliz@gnu.org>]

> Date: Wed, 18 Oct 2023 08:17:07 +0200
> From:  Jens Östlund via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> When sending an email with 'smtpmail-send-it' the function 'smtpmail-try-auth-methods' fails to find the matching entry. Using 'edebug' I've found that the reason is this piece of code where the 'port' is converted to a string (smtpmail.el.gz:533-536):
> 
> '(setq port
> 	(if port
> 	    (format "%s" port)
> 	  "smtp"))'
> 
> When the 'port' is later passed to 'auth-source-search' on line 541 it fails to find any matching entries since ':port' is matched as a number, not a string. If I remove the above piece of code, so that 'port' is never turned into a string, sending the email works as expected. Maybe the best solution is to make 'auth-source-search' match both numeric and string values, at least for the ':port' argument.
> 
> SMTP session trace:
> 
> '220 mailrelay6 ESMTP
> 250-mailrelay6
> 250-PIPELINING
> 250-CHUNKING
> 250-SIZE 104857600
> 250-AUTH LOGIN PLAIN
> 250-ENHANCEDSTATUSCODES
> 250 8BITMIME
> MAIL FROM:<xxxxxxx@xxxxxx.xx> SIZE=322
> 550 5.7.1 [M1] Authentication required (431ff6c7-6d37-11ee-accc-23968f462fbe)
> QUIT
> 221 2.0.0 Bye
> 
> Process smtpmail connection broken by remote peer’

Thanks.

I guess I'm missing something, because I use smtpmail with
authentication and a specific port all the time without any trouble.
So maybe show the entry from your ~/.authinfo?

Also, can you point me to the place where you see that port is matched
as a number?  See also bug#55199, where a similar problem was fixed,
and the fix should be in Emacs 29.1.  Maybe you have a stale
auth-sources.elc?