[Extra] [Technical Errata Reported] RFC9051 (7343)

RFC Errata System <rfc-editor@rfc-editor.org> Mon, 13 February 2023 19:24 UTC

To: Alexey.Melnikov@isode.com, barryleiba@computer.org, superuser@gmail.com, francesca.palombini@ericsson.com, yaojk@cnnic.cn, brong@fastmailteam.com
From: RFC Errata System <rfc-editor@rfc-editor.org>
Cc: nicholas.evans@gmail.conm, extra@ietf.org, rfc-editor@rfc-editor.org
Content-Type: text/plain; charset="UTF-8"
Message-Id: <20230213192451.EAA55563F7@rfcpa.amsl.com>
Date: Mon, 13 Feb 2023 11:24:51 -0800
Archived-At: <https://mailarchive.ietf.org/arch/msg/extra/jKNAkHfCZ1E4WMr50w7sDrj6lWg>
Subject: [Extra] [Technical Errata Reported] RFC9051 (7343)
Precedence: list

The following errata report has been submitted for RFC9051,
"Internet Message Access Protocol (IMAP) - Version 4rev2".

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You may review the report below and at:
https://www.rfc-editor.org/errata/eid7343

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Type: Technical
Reported by: Nicholas Evans <nicholas.evans@gmail.conm>

Section: 9

Original Text
-------------
resp-cond-auth  = ("OK" / "PREAUTH") SP resp-text
                    ; Authentication condition

resp-cond-bye   = "BYE" SP resp-text

resp-cond-state = ("OK" / "NO" / "BAD") SP resp-text
                    ; Status condition

...

resp-text       = ["[" resp-text-code "]" SP] [text]



Corrected Text
--------------
resp-cond-auth  = ("OK" / "PREAUTH") [SP resp-text]
                    ; Authentication condition
                    ;
                    ; Servers SHOULD send the trailing SP when resp-text
                    ; is empty.
                    

resp-cond-bye   = "BYE" [SP resp-text]
                    ; Servers SHOULD send the trailing SP when resp-text
                    ; is empty.

resp-cond-state = ("OK" / "NO" / "BAD") [SP resp-text]
                    ; Status condition
                    ;
                    ; Servers SHOULD send the trailing SP when resp-text
                    ; is empty.

...


resp-text       = "[" resp-text-code "]" [SP [text]] / [text]
                    ; Servers SHOULD send then trailing SP when
                    ; resp-text-code is present but text is empty.

Notes
-----
Appendix E, Changes from RFC 3501 / IMAP4rev1, item 23 states that "resp-text ABNF non-terminal was updated to allow for empty text."

In the spirit of Appendix E. 23, resp-text should allow "[" resp-text-code "]" without a trailing SP.  Similarly, resp-cond-auth, resp-cond-bye, and resp-cond-state should also allow the trailing SP to be dropped when resp-text is empty.  In all of these cases, the missing SP does not change the semantics of the response, so clients should not require it to be present.  However, for compatibility with clients that strictly adhere to the formal syntax as-is, servers should conservatively send the trailing SP even when text or resp-text is empty.

This aligns with existing practice, as some existing IMAP4rev1 servers already fail to send these trailing spaces, and some liberal clients already allow them to be missing.

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RFC9051 (draft-ietf-extra-imap4rev2-30)
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Title               : Internet Message Access Protocol (IMAP) - Version 4rev2
Publication Date    : August 2021
Author(s)           : A. Melnikov, Ed., B. Leiba, Ed.
Category            : PROPOSED STANDARD
Source              : Email mailstore and eXtensions To Revise or Amend
Area                : Applications and Real-Time
Stream              : IETF
Verifying Party     : IESG

[Extra] [Technical Errata Reported] RFC9051 (7343) RFC Errata System