Regression in Ubuntu 22.04: Content of form field stored invisibly

[Philipp Wendler]

[ Impact ]

The bug causes text entered in certain PDF form fields to be stored but both displayed and printed white (on white background).

[ Test Plan ]

1. Download the attached 230-muster-01.pdf.
2. Try to input to any of the main content fields starting with 06-09 ("Anrede des Zahlungspflichtigen etc").
3. Observe that it does not work.
4. Install the updated poppler package versions
5. Try the same fields and see they're functoning properly now with visible text.
6. Test also that the fields like "Aktenzeichen", "TL-Nr." or "Buchungsstelle" that weren't broken, continue to work.

[ Where problems could occur ]

It is a merged upstream fix to Annot.cc file that fixed two upstream bugs https://gitlab.freedesktop.org/poppler/poppler/-/issues/1189 and https://gitlab.freedesktop.org/poppler/poppler/-/issues/1267.

There are no indications of upstream regressions caused by this fix, and it was released in upstream stable release 22.08.0 (Ubuntu 22.04 LTS has version based on 22.02.0).

However, since it's an individual cherry-pick there could always be a PDF somewhere having issues with this, so it's useful to let it be tested with various files in addition to the problematic ones.

--- original report ---

Evince on Ubuntu 22.04 is not able to handle some PDF forms correctly anymore that it was able to handle on Ubuntu 21.10 and on Ubuntu 20.04.

The symptom is that one can edit the form content and also save it, but that the entered text is only visible when the form field is focused and in edit mode. Otherwise the text it is invisible, also on printouts.

Such bugs have been reported against Evince for a long time (e.g., https://bugs.launchpad.net/ubuntu/+source/poppler/+bug/265033) but I am reporting this as a new bug because for the current form with which I am experiencing this it is a regression.

I have attached the problematic form with two form fields filled out, one in the upper left corner and the big one in the lower half.
I have produced this by taking the original, empty form (produced by somebody else) and first opened it in Evince 41.4, which I have installed from the snap package (revision 1017) on Ubuntu 22.04. I entered text in the upper left field and saved the form.
Then I opened the PDF in Evince 42.3 from the apt package of Ubuntu 22.04 and entered text in the big field and saved the form.

Evince 3.36 on Ubuntu 20.04 has the same (correct) behavior as Evince 41.4.

When I open the PDF again, only the text in the first field is visible. The text in the second field is visible only if I click into the field. The visibility of the field contents is the same for Evince 41.4 (snap), Evince 42.3 (apt), and Okular 20.12.3 (snap). So it seems that the problem is with Evince 42.3 incorrectly saving the field content, not with displaying it.

Firefox shows and prints the content of both fields, though.

Note that I cannot switch back to Evince 41 because for some other forms that I have the exact same problem happens only with the old version and the new version fixes it. So it seems that something changed that fixed it for some forms and broke it for others.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: evince 42.3-0ubuntu1
ProcVersionSignature: Ubuntu 5.15.0-40.43-generic 5.15.35
Uname: Linux 5.15.0-40-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: ubuntu:GNOME
Date: Wed Jul 6 14:32:27 2022
InstallationDate: Installed on 2021-11-26 (222 days ago)
InstallationMedia: Ubuntu 21.10 "Impish Indri" - Release amd64 (20211012)
RebootRequiredPkgs: Error: path contained symlinks.
Snap.Changes:
 ID Status Spawn Bereit Zusammenfassung
 137 Done 2022-07-06T12:48:33+02:00 2022-07-06T12:48:41+02:00 Installiere "evince" Snap
SourcePackage: evince
UpgradeStatus: Upgraded to jammy on 2022-06-22 (13 days ago)

[Philipp Wendler (philw85)]

I found out that the bug is actually in poppler and have reported a bug upstream, where it is being worked on.

[Philipp Wendler (philw85)]

A fix has been committed upstream now. Could this be backported to Ubuntu?

I tested https://gitlab.freedesktop.org/poppler/poppler/-/commit/a89c3c27e02e9c300aa667c966d91fdf787c7d0a by cherry-picking it on top of poppler-22.02.0. Tt applies and compiles cleanly and with it Evince on Ubuntu 22.04 behaves as it should with respect to form fields for several PDFs that I checked, including the original problematic file.

[Philipp Wendler (philw85)]

I would like to repeat that this is a regression in Ubuntu 22.04, it has a fix released upstream and the patch applies cleanly if backported. So it seems that this should be a low hanging fruit to fix and I would really appreciate it if the fix could be shipped to Ubuntu 22.04. Thank you very much in advance!

[Timo Jyrinki (timo-jyrinki)]

I have a PDF form that provably works in 20.04's version of Evince (poppler) but does not in 22.04, so came to search for an existing bug.

I can confirm this patch fixes the issue for me too on 22.04. I built it now at https://launchpad.net/~timo-jyrinki/+archive/ubuntu/poppler-jammy and confirmed it works. Annoyingly publishing is taking ages so the PPA repository is not ready yet, but I downloaded the debs manually from the amd64 build for testing.

Since I happen to be a Ubuntu developer too, I now uploaded it with the correct version number to the jammy's queue https://launchpad.net/ubuntu/jammy/+queue?queue_state=1&queue_text=poppler - let's see if it will get accepted eventually in the proposed SRUs from there. If it will, this bug will be updated asking for a verification of the fix by using the exact version from proposed to get it forward.

[Timo Aaltonen (tjaalton)]

the upload is fine, but could you please fix the description to have the necessary SRU information described here:

https://wiki.ubuntu.com/StableReleaseUpdates#SRU_Bug_Template

[Timo Jyrinki (timo-jyrinki)]

SRU information added.

[Timo Aaltonen (tjaalton)]

Hello Philipp, or anyone else affected,

Accepted poppler into jammy-proposed. The package will build now and be available at https://launchpad.net/ubuntu/+source/poppler/22.02.0-2ubuntu0.4 in a few hours, and then in the -proposed repository.

Please help us by testing this new package. See https://wiki.ubuntu.com/Testing/EnableProposed for documentation on how to enable and use -proposed. Your feedback will aid us getting this update out to other Ubuntu users.

If this package fixes the bug for you, please add a comment to this bug, mentioning the version of the package you tested, what testing has been performed on the package and change the tag from verification-needed-jammy to verification-done-jammy. If it does not fix the bug for you, please add a comment stating that, and change the tag to verification-failed-jammy. In either case, without details of your testing we will not be able to proceed.

Further information regarding the verification process can be found at https://wiki.ubuntu.com/QATeam/PerformingSRUVerification . Thank you in advance for helping!

N.B. The updated package will be released to -updates after the bug(s) fixed by this package have been verified and the package has been in -proposed for a minimum of 7 days.

[Ubuntu SRU Bot (ubuntu-sru-bot)]

All autopkgtests for the newly accepted poppler (22.02.0-2ubuntu0.4) for jammy have finished running.
The following regressions have been reported in tests triggered by the package:

xapers/0.9.0-1 (armhf)

Please visit the excuses page listed below and investigate the failures, proceeding afterwards as per the StableReleaseUpdates policy regarding autopkgtest regressions [1].

https://people.canonical.com/~ubuntu-archive/proposed-migration/jammy/update_excuses.html#poppler

[1] https://wiki.ubuntu.com/StableReleaseUpdates#Autopkgtest_Regressions

Thank you!

[Philipp Wendler (philw85)]

Tested with 22.02.0-2ubuntu0.4 and working fine. Thanks!

[Timo Jyrinki (timo-jyrinki)]

Autopkgtest problem on armhf only, resolved with a rerun.