Default options not retrieved correctly

[metabiswadeep]

Describe the bug
While working on fixing default options not being retrieved correctly by CPDB, I found that the CUPS is not returning the values of the default options correctly. It can be seen that default options are retrieved by https://github.com/OpenPrinting/cpdb-backend-cups/blob/master/src/backend_helper.c#L688 and it seems that the wrong default value is retrieved here, atleast for the case of resolution for a dummy printer instance of default resolution 1200dpi. It goes on to https://github.com/OpenPrinting/cpdb-backend-cups/blob/master/src/backend_helper.c#L701 which then goes to https://github.com/OpenPrinting/cpdb-backend-cups/blob/master/src/backend_helper.c#L1955 then to https://github.com/OpenPrinting/cpdb-backend-cups/blob/master/src/backend_helper.c#L1967 which gives 300 as the output though it should give 1200. It seems that the CUPS calls being made here are not returning the correct default values.

Expected behavior
The correct default value should get returned from CUPS.

System Information:

• Ubuntu 23.10
• CUPS version 2.4.6

[michaelrsweet]

Have you tested with the most recent version of CUPS? 2.4.6 is getting a little old and there have been several bug fixes WRT defaults since then...

[metabiswadeep]

Hey, sorry for the late reply. Yes I tried on the master branch and it still does not return the correct default options.

[LumioseSil]

Describe the bug While working on fixing default options not being retrieved correctly by CPDB, I found that the CUPS is not returning the values of the default options correctly. It can be seen that default options are retrieved by https://github.com/OpenPrinting/cpdb-backend-cups/blob/master/src/backend_helper.c#L688 and it seems that the wrong default value is retrieved here, atleast for the case of resolution for a dummy printer instance of default resolution 1200dpi. It goes on to https://github.com/OpenPrinting/cpdb-backend-cups/blob/master/src/backend_helper.c#L701 which then goes to https://github.com/OpenPrinting/cpdb-backend-cups/blob/master/src/backend_helper.c#L1955 then to https://github.com/OpenPrinting/cpdb-backend-cups/blob/master/src/backend_helper.c#L1967 which gives 300 as the output though it should give 1200. It seems that the CUPS calls being made here are not returning the correct default values.

Expected behavior The correct default value should get returned from CUPS.

System Information:

• Ubuntu 23.10
• CUPS version 2.4.6

Is there a way to repro the issue? What did you do to get this to happen?

[metabiswadeep]

@AZero13 You can reproduce this by using the Common Print Dilog Backends(CPDB), a software by OpenPrinting that currently provides support for CUPS as a backend. I created a dummy printer in CUPS with a default resolution of 1200dpi. Then after running cpdb-text-frontend and doing get-default printer-resolution <printer_id> CUPS I got 300 dpi as the output though it should be giving 1200 dpi as the output.

[tillkamppeter]

@metabiswadeep could you perhaps write a small example program which does nothing more than the same request to CUPS as the CPDB backend does to see whether CUPS really gives the wrong answer?