libcupsfilters 2.2.1-2 breaks custom continuous media on Brother QL-820NWB

[patroza]

Summary

After upgrading Arch Linux libcupsfilters from 2.1.1-4 to
2.2.1-2, print jobs to a Brother QL-820NWB using the
Foomatic/ptouch-ql driver fail.

The printer reports that the installed roll is the wrong type. CUPS
records job-canceled-at-device / other-error.

Downgrading only libcupsfilters to 2.1.1-4 and restarting CUPS
immediately restores printing with the same queue, documents, and media
settings.

Configuration

• Printer: Brother QL-820NWB
• Installed media: 62 mm continuous roll
• Driver: Brother QL-820NWB Foomatic/ptouch-ql (recommended)
• printer-driver-ptouch 1.7.1-1
• PageSize=Custom.61.98x183.90mm
• MediaType=Tape
• Transport: DNS-SD/IPP

Other package versions:

• cups 2:2.4.19-1
• cups-filters 2.0.1-2
• libppd 2.1.1-2
• printer-driver-ptouch 1.7.1-1

Reproduction

1. Install libcupsfilters 2.2.1-2.

2. Restart CUPS.

3. Submit a job using:

   • PageSize=Custom.61.98x183.90mm
   • MediaType=Tape

4. The printer rejects the job as using the wrong roll type.

5. CUPS reports job-canceled-at-device / other-error.

6. Downgrade only libcupsfilters:

   sudo pacman -U /var/cache/pacman/pkg/libcupsfilters-2.1.1-4-x86_64.pkg.tar.zst
   sudo systemctl restart cups
   

7. Resubmit the same jobs. They print successfully.

Local A/B results

With libcupsfilters 2.2.1-2:

• Job 4: canceled-at-device
• Job 5: canceled-at-device

Immediately after downgrading to 2.1.1-4:

• Job 9: job-completed-successfully
• Job 10: job-completed-successfully

The printer configuration and printer-driver-ptouch package did not
change between these tests.

Expected behavior

The custom-length job should print on the installed 62 mm continuous
roll, as it does with libcupsfilters 2.1.1-4.

Actual behavior

The printer detects a media mismatch and cancels the job.

Additional notes

foomatic-rip links against libcupsfilters.so.2, so changing only
libcupsfilters affects this legacy PPD/filter path.

Upstream libcupsfilters 2.2.0 substantially rewrote PDF and raster
processing, replacing QPDF/libpoppler internals with PDFio. Therefore
this may be a custom-page-size or raster-header regression introduced
in 2.2.0 and included in 2.2.1.

I can provide paired debug logs or run a 2.2.0-versus-2.1.1 test if
needed.

[dkaparis]

Probably related. Upgrading to 2.2.1-2 on artix linux breaks printing with Brother MFC-L2710DN series, using Owl-Maintain/brlaser v6.2.8, jobs failing with message "cfFilterChain: pdftopdf (PID xxxx) stopped with status 1". Again, downgrading just libcupsfilters to 2.1.1-4 and restarting cupsd, printing jobs run fine.