Bug#704238: Need to document the CUPS client's new server-version option

[Michael Sweet <msweet@apple.com>]

Daniel,

On 2013-06-20, at 11:38 PM, Daniel Richard G. <skunk@iskunk.org> wrote:
> ...
> Now that it is possible to configure a new client to talk with an old
> server, and that the means of doing so is documented (in Debian
> currently, and upstream soon), we need this problem to be diagnose-able.

Well, before we go off and spend extra engineering time on this, how widespread is the use of client.conf in the Linux world? On OS X it was pretty-much non-existent (less than 1% of users, based on bug reports) and since 10.8 *is* non-existent since we had to drop support for it entirely there (not all applications ask for networking access, and without network access you can't talk to a remote cupsd...)

> ...
> I think that lpq and lpstat (any others?), being the most obvious tools
> for verifying basic connectivity with the CUPS server, need to go the
> extra mile to detect this kind of situation so that the user can be
> alerted to it. Maybe if the tool gets a "Bad Request" error, it can do a
> version probe... whatever makes the most sense. I'm not going to argue
> for automatic protocol downgrading when that's already been considered,
> but I will argue that returning a nonspecific "Bad Request" error (or
> spurious "Unknown destination" error) for this particular failure mode
> places an unacceptable burden on users wondering why their latest and
> greatest Linux system is unable to print at all.
> 
> (I would agree that a "cupsversion" utility isn't such a hot idea,
> albeit because the user would have to be aware of the IPP version being
> an issue in order to know to use such a utility in the first place.)


Would simply adding some additional text to the client.conf man page be just as helpful, e.g.:

       ServerName hostname-or-ip-address[:port]/version=1.1
            Specifies the address and optionally the port to use when connect-
            ing to a server running CUPS 1.3.12 or earlier. Note: Not support-
            ed on OS X 10.7 or later.

       ServerName hostname-or-ip-address[:port]

       ServerName /domain/socket
            Specifies the address and optionally the port to use when connect-
            ing to a server running CUPS 1.4 or later. Note: Not supported on
            OS X 10.7 or later.

_________________________________________________________
Michael Sweet, Senior Printing System Engineer, PWG Chair