SHOULD requirement on accepting trailing spaces in commands in section 4.1.1

[aamelnikov]

Donald Eastlake wrote:

Section 4.1.1: Suggest removing the parenthesis around the parenthetical. It seems like a fine top-level sentence and a reader might wonder why it is in parenthesis. For example, they might somehow think that it weakens the "SHOULD".

The text in question is:

The SMTP commands define the mail transfer or the mail system function requested by the user. SMTP commands are character strings terminated by . The commands themselves are alphabetic characters terminated by if parameters follow and otherwise. (In the interest of improved interoperability, SMTP receivers SHOULD tolerate trailing white space before the terminating

.) The syntax of the local part of a mailbox MUST conform to receiver site conventions and the syntax specified in Section 4.1.2. The SMTP commands are discussed below. The SMTP replies are discussed in Section 4.2.

[aamelnikov]

John Klensin replied to this:

I think I agree but, historically, RFC 2821 used a version of the sentence without the "SHOULD". RFC 5321 introduced the SHOULD (and retained the parentheses). That trailing white space really should (sic) not be there so maybe this is a weak "SHOULD".

and also later added:

While, conceptually, I think we both know what I meant by "weak SHOULD", BCP 14 does not identify such things, adding to my hesitancy to mess with this.

[aamelnikov]

So far the suggestion is "no change".