Re: Arguments to checkgroups control messages

Harald Alvestrand <[email protected]> writes:

> It seems to me that since we're incompatible with something people
> will also know about (wildmat), flagging the incompatibility is
> important.
>
> We can't go on making changes in AUTH48 (it's never going to be
> perfect), but if there's another reason for a delay and a diff, adding
> a sentence pointing out the semantic difference would be good.

I was thinking that we could just say that all the exclusions should go
after the scope, but I forgot that we explicitly intended to permit
multiple scopes for the same checkgroups.

Here's a diff of the proposed change.  USEPRO is still blocked on
USEFOR, so we're not holding anything up at the moment, although I agree
that we really need to stop making changes at some point soon.  I've not
yet sent it to the RFC Editor pending discussion here.

This patch doesn't point out a difference with wildmat specifically;
instead, it specifies the algorithm that one should use.  That avoids
introducing a concept that isn't already present in USEPRO and I think
is even more precise than a caution.

Index: usepro.xml
===================================================================
--- usepro.xml	(revision 5949)
+++ usepro.xml	(working copy)
@@ -2022,14 +2022,24 @@
           the valid groups in all hierarchies or sub-hierarchies with a
           prefix listed in the &lt;chkscope> argument, excluding any
           sub-hierarchy where the &lt;chkscope> argument is prefixed by
-          "!".  If no &lt;chkscope> argument is given, it applies to all
+          "!".  For complex cases with multiple &lt;chkscope> arguments,
+          start from an empty list of groups, include all groups in the
+          checkgroups control message matching &lt;chkscope> arguments
+          without a "!" prefix, and then exclude all groups matching
+          &lt;chkscope> arguments with a "!" prefix.  Follow this method
+          regardless of the order of the &lt;chkscope> arguments in the
+          Control header field.</t>
+
+          <t>If no &lt;chkscope> argument is given, it applies to all
           hierarchies for which group statements appear in the body of the
-          message.  Since much existing software does not honor the
-          &lt;chkscope> argument, the body of the checkgroups control
-          message MUST NOT contain group statements for newsgroups outside
-          the intended scope and SHOULD contain a correct newsgroup list
-          even for sub-hierarchies excluded with "!" &lt;chkscope> terms.
-          News servers, however, MUST honor &lt;chkscope> as specified
+          message.</t>
+
+          <t>Since much existing software does not honor the &lt;chkscope>
+          argument, the body of the checkgroups control message MUST NOT
+          contain group statements for newsgroups outside the intended
+          scope and SHOULD contain a correct newsgroup list even for
+          sub-hierarchies excluded with "!" &lt;chkscope> terms.  News
+          servers, however, MUST honor &lt;chkscope> as specified
           here.</t>
 
           <t>The &lt;chksernr> argument may be any positive integer.  If


-- 
Russ Allbery ([email protected])             <http://www.eyrie.org/~eagle/>