Comment # 17 on bug 1128467 from Johannes Meixner

Martin Wilck,
regarding your comment#14 "transition from HPIJS to HPCUPS":

In general when a printer driver is dropped
existing print queues that use that driver will no longer work,
usually with a not really informative "Filter failed" message:
---------------------------------------------------------------------------
# lpadmin -p hpijstest -v file:///dev/null \
 -P /usr/share/cups/model/manufacturer-PPDs/hplip/hp-910-hpijs.ppd.gz\
 -E

# echo hello1 | lp -d hpijstest -t test1

# mv /usr/bin/hpijs /usr/bin/hpijs.away

# echo hello2 | lp -d hpijstest -t test2

# lpstat -p hpijstest
printer hpijstest is idle.  enabled since Mon 11 Mar 2019 09:06:11 CET
        Filter failed

# grep PID /var/log/cups/error_log
...
D [11/Mar/2019:09:06:11 +0100] [Job 18] PID 8550 \
 (/usr/lib/cups/filter/foomatic-rip) stopped with status 9.

# less /var/log/cups/error_log
...
D [11/Mar/2019:09:06:11 +0100] [Job 18]
 Starting renderer with command: gs -dShowAcroForm  -q -dBATCH
 -dPARANOIDSAFER -dQUIET -dNOPAUSE -sDEVICE=ijs -sIjsServer=hpijs
 -dDEVICEWIDTHPOINTS=612 -dDEVICEHEIGHTPOINTS=792
 -sDeviceManufacturer=\"HEWLETT-PACKARD\"
 -sDeviceModel=\"deskjet 3600\" -r300
 -sIjsParams=Quality:Quality=0,Quality:ColorMode=2,
             Quality:MediaType=0,Quality:PenSet=1
 -dIjsUseOutputFD -sOutputFile=-   /var/spool/cups/tmp/foomatic-h902Zw 
...
D [11/Mar/2019:09:06:11 +0100] [Job 18]
 sh: hpijs: command not found
D [11/Mar/2019:09:06:11 +0100] [Job 18]
 GPL Ghostscript 9.26: Can\'t start ijs server \"hpijs\"
D [11/Mar/2019:09:06:11 +0100] [Job 18]
 **** Unable to open the initial device, quitting.
D [11/Mar/2019:09:06:11 +0100] [Job 18]
 renderer exited with status 1
D [11/Mar/2019:09:06:11 +0100] [Job 18]
 Possible error on renderer command line or PostScript error.
 Check options.Kid3 exit status: 3
D [11/Mar/2019:09:06:11 +0100] [Job 18] PID 8550
 (/usr/lib/cups/filter/foomatic-rip) stopped with status 9.
---------------------------------------------------------------------------
Only with "LogLevel debug" one may notice in /var/log/cups/error_log
the "sh: hpijs: command not found" which points to the root cause.

Currently I have no good idea for a smooth transition from HPIJS to HPCUPS.
In particular I have no idea how to tell the user the root cause why his
existing HPIJS queue does no longer work.

We might first drop the
/usr/share/cups/model/manufacturer-PPDs/hplip/*-hpijs.ppd.gz
and
/usr/share/cups/model/manufacturer-PPDs/hplip-plugin/*-hpijs.ppd.gz
PPD files from the hplip-hpijs and hplip RPMs
but keep /usr/bin/hpijs
so that uses can no longer set up new print queues with HPIJS
but existing queues that use HPIJS will still work
(PPDs for existing queues are in /etc/cups/ppd/).

Then we could wait (how long?) and hope that very most of the
existing queues that use HPIJS somehow faded away.

Finally we could drop /usr/bin/hpijs (still existing HPIJS queues
will then no longer work as described above).