Bug#982925: libgtk: print dialog lists autodetected printer twice

[Simon McVittie]

On Sun, 20 Feb 2022 at 17:19:36 +0000, Simon McVittie wrote:
> I will reply to the bug with my own test results.

> * Which versions of cups-daemon and cups-filters-core-drivers are installed?

cups-daemon	2.3.3op2-3+deb11u1
cups-filters-core-drivers	1.28.7-1

> * How many printers are physically present on your network?

One HP Color LaserJet MFP M277dw.

> * Is cups-browsed installed? If yes, which version?

I tested both with and without cups-browsed 1.28.7-1.

Test methodology for each of the 12 attempts listed here (I'm using an
expendable test machine, do not do these steps unless you are willing
to lose manual CUPS configuration):

sudo apt purge cups-browsed cups-daemon
sudo rm -fr /etc/cups
sudo apt install cups cups-core-drivers cups-daemon cups-browsed-
(optionally) Configure printer: gnome-control-center, Printers, Unlock,
             Add..., wait, click on the single printer that appears, Add
(optionally) sudo apt install cups-browsed
G_MESSAGES_DEBUG=all gedit
Try to print

GTK 3.24.24-4 (status quo in bullseye)
======================================

                                    | cups-browsed installed |
                                    |    no      | yes       |
    --------------------------------|------------|-----------|
    printer manually configured   no|unavailable | works     |
                                 yes| works      |duplicated |
    --------------------------------|------------|-----------|

With no configuration and no cups-browsed: No printers are listed

With cups-browsed only: One printer, HP_Color_LaserJet_MFP_M277dw_xxxxxx_,
where xxxxxx is a unique ID taken from its MAC address. It appears in
/etc/cups/printers.conf, flagged as having come from cups-browsed.
Printing is successful.

With manual configuration only: One printer, HP-Color-LaserJet-MFP-M277dw.
It appears in /etc/cups/printers.conf. Printing is successful.

With both: both of the printers mentioned above appear in the GTK dialog
and in /etc/cups/printers.conf. Both print successfully.

GTK with merge request 9 (Daniel's minimal backport)
====================================================

                                    | cups-browsed installed          |
                                    |    no      | yes                |
    --------------------------------|------------|--------------------|
    printer manually configured   no| unavailable|duplicated          |
                                 yes| works      |dup., only one works|
    --------------------------------|------------|--------------------|

With no configuration and no cups-browsed: No printers are listed

With cups-browsed only: One printer, HP_Color_LaserJet_MFP_M277dw_xxxxxx_,
where xxxxxx is a unique ID taken from its MAC address. Printing is successful.

With manual configuration only: One printer, HP-Color-LaserJet-MFP-M277dw.
It appears in /etc/cups/printers.conf. Printing is successful.

With both: both of the printers mentioned above appear in the GTK dialog
and in /etc/cups/printers.conf. Only the first one printed successfully:
the second logged "NO_DEST_FOUND".

GTK with merge request 6 (full backport from 3.24.29)
=====================================================

                                    | cups-browsed installed |
                                    |    no      | yes       |
    --------------------------------|------------|-----------|
    printer manually configured   no| works      |duplicated |
                                 yes| works      |duplicated |
    --------------------------------|------------|-----------|

With no configuration and no cups-browsed: One printer appears in the
GTK dialog, HP_Color_LaserJet_MFP_M277dw_xxxxxx. Printing is successful.

With cups-browsed only: Two printers appear, labelled
HP_Color_LaserJet_MFP_M277dw_xxxxxx and HP_Color_LaserJet_MFP_M277dw_xxxxxx_.
Only the second one appears in /etc/cups/printers.conf, labelled as having
come from cups-browsed. Both print successfully.

With manual configuration only: One printer, HP-Color-LaserJet-MFP-M277dw.
It appears in /etc/cups/printers.conf. Printing is successful.

With both: Two printers appear, labelled HP-Color-LaserJet-MFP-M277dw
and HP_Color_LaserJet_MFP_M277dw_xxxxxx_. Both are in /etc/cups/printers.conf,
with the second one labelled as having come from cups-browsed. Both print
successfully.