Re: Rmail: 'reply' vs 'reply-all'?

[Christopher Pinon <cjpinon@secondfloor.xyz>]

Christopher Pinon <cjpinon@secondfloor.xyz> writes:

> Christopher Pinon <cjpinon@secondfloor.xyz> writes:
>
>> Eli Zaretskii <eliz@gnu.org> writes:
>>
>>>> From: Christopher Pinon <cjpinon@secondfloor.xyz>
>>>> 
>>>> https://www.gnu.org/software/emacs/manual/html_node/emacs/Rmail-Reply.html
>>>> 
>>>> suggests (on my reading) that typing 'r' will add the 'CC' field to the
>>>> header if the incoming message contains recipients in this field. In
>>>> contrast, typing 'C-u r' will omit the 'CC' field entirely.
>>>> 
>>>> Unfortunately, in my testing, typing 'r' (like 'C-u r') omits the 'CC'
>>>> field when the incoming message contains recipients in this field, and I
>>>> have to add this field manually if I want to have it.
>>>
>>> That's not what I see here, with Rmail: 'r' responds to the "From"
>>> address, and places all the addresses from "To" and "CC" (if any) in
>>> the "CC" field of the response.  "C-u r" produces a response with a
>>> single address in "To", and no "CC".
>>>
>>> I wonder why this doesn't happen to you.  Maybe you have some
>>> customizations which cause this?
>>
>> I have very few customizations to begin with, and certainly none that
>> redefine 'reply' functions (am using stock Emacs 25.1). No fancy stuff
>> whatsoever!
>>
>> I just did some further tests, sending mail to myself from other
>> accounts, putting multiple recipients in "CC" and/or "To". The behavior
>> is the same: 'r' just puts the sender into "To". :-(
>>
>> I recall experimenting with Rmail last year using Emacs 24.5, and I
>> witnessed the same behavior as now regarding 'r' (again, during my
>> tests). In fact, last year I gave up on Rmail for this reason, but now
>> decided to try again.
>>
>> Strange. I guess that I have to do further tests. (Otherwise I like
>> Rmail!)
>
> As a follow-up to myself, I would like to share what I found.

[For the sake of clarity, I've reformatted my previous message. Although
I naturally didn't use real email addresses, I had forgotten that even
fake addresses would be disguised. Sorry about this.]

During my private tests, I used three other email addresses that I have:
myusername AT domain1, myusername AT domain2, and myusername AT
domain3. These are different addresses (because different domains), but
'myusername' is the same in each case. What I found is that 'r' in Rmail
did not add these addresses to "CC" or "To", which is what puzzled me.

As soon as I used an address of the form anotherusername AT domain in
"CC" or "To", 'r' in Rmail behaved as expected (i.e., as according to
the manual) and added it to "CC" or "To".

In sum, 'r' in Rmail appears to treat the addresses myusername AT
domain1, myusername AT domain2, and myusername AT domain3 as the same
address, which is a bit unfortunate. In practice, it's not likely to be
a significant issue (it was an artifact of my private tests), but it
nevertheless seems a little odd for 'r' in Rmail to treat such addresses
as the same.

C.