[ietf-nntp] ARTICLE message-id returning article number

[Clive D.W. Feather]

I've now added the text to permit this. Changes as follows:

ARTICLE:

-          220 0 message-id   Article follows (multiline)
+          220 0|n message-id   Article follows (multiline)      

(and similarly in HEAD, BODY, and STAT).

-    In the response, the article number is replaced with zero (that is,
-    the server is not required to determine whether the article is in the
-    current selected newsgroup or what article number(s) it has).
+    In the response, the article number MUST be replaced with zero,
+    except that if there is a current selected group and the article has
+    is in that group, the server MAY use that article number. (The server
+    is not required to determine whether the article is in the current
+    selected newsgroup or, if so, what article number it has. The client
+    MUST always be prepared for zero to be specified.) The server MUST
+    NOT provide an article number unless use of that number in a second
+    ARTICLE command immediately following this one would return the same 
+    article. Even if the server chooses to return article numbers in
+    these circumstances, it need not do so consistently; it MAY return
+    zero to any such command (also see the STAT examples (Section
+    6.2.4.3)).

STAT examples:

+    Example of STAT by message-id on a server which sometimes reports the
+    actual article number:
+
+       [C] GROUP   misc.test
+       [S] 211 1234 3000234 3002322 misc.test
+       [C] STAT
+       [S] 223 3000234 <45223423 at example.com> 
+       [C] STAT   <45223423 at example.com>
+       [S] 223 0 <45223423 at example.com>
+       [C] STAT   <45223423 at example.com>
+       [S] 223 3000234 <45223423 at example.com>
+       [C] GROUP   example.empty.newsgroup
+       [S] 211 0 0 0 example.empty.newsgroup
+       [C] STAT   <45223423 at example.com>
+       [S] 223 0 <45223423 at example.com>
+       [C] GROUP   alt.crossposts
+       [S] 211 9999 111111 222222 alt.crossposts
+       [C] STAT   <45223423 at example.com>
+       [S] 223 123456 <45223423 at example.com>
+       [C] STAT
+       [S] 223 111111 <23894720 at example.com>
+
+    The first STAT command establishes the identity of an article in the
+    group. The second and third show that the server may, but need not,
+    give the article number when the message-id is specified. The fourth
+    STAT command shows that zero must be specified if the article isn't
+    in the current selected group, the fifth shows that the number, if
+    provided, must be that relating to the current selected group, and
+    the last one shows that the current selected article is still not
+    changed by the use of STAT with a message-id even if it returns an
+    article number.

OVER:

-       "0" (first form) or article number (second form)
+       "0" or article number (see below)

-    If the article is specified by message-id rather than by article 
-    range, the article number is given as "0".
+    If the article is specified by message-id (the first form of the
+    command), the article number MUST be replaced with zero, except that
+    if there is a current selected group and the article has is in that
+    group, the server MAY use that article number (see the ARTICLE
+    command (Section 6.2.1) and STAT examples (Section 6.2.4.3) for more
+    details). In the other two forms of the command, the article number
+    MUST be returned.

HDR:

     item. In the case of a header, the header name, colon, and the first
-    space after the colon are all omitted. If the article is specified by
-    message-id, the article number is given as "0".
+    space after the colon are all omitted.
+       
+    If the article is specified by message-id (the first form of the
+    command), the article number MUST be replaced with zero, except that
+    if there is a current selected group and the article has is in that
+    group, the server MAY use that article number (see the ARTICLE
+    command (Section 6.2.1) and STAT examples (Section 6.2.4.3) for more
+    details). In the other two forms of the command, the article number
+    MUST be returned.

-- 
Clive D.W. Feather  | Work:  <clive at demon.net>   | Tel:    +44 20 8495 6138
Internet Expert     | Home:  <clive at davros.org>  | *** NOTE CHANGE ***
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