Bug#945989: apngdis producing blank images

[Madars <mad182@gmail.com>]

Package: apngdis
Version: 2.5-2
Severity: grave
Tags: a11y
Justification: renders package unusable

Dear Maintainer,

apngdis is not working properly on Debian Buster.

It's producing a list of blang (black) images. It happened to any apng files I tested.

First I discovered this issue on production server, then repeated on freshly installed and updated minimal installation with only this package installed.

To reproduce the issue:
wget https://upload.wikimedia.org/wikipedia/commons/1/14/Animated_PNG_example_bouncing_beach_ball.png
apngdis Animated_PNG_example_bouncing_beach_ball.png

This command should generate seperate images for each animation frame.

On jessie it's working as expected, but on buster runs very quickly and generates a list of identical black images. There are no errors displayed.


-- System Information:
Debian Release: 10.2
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-6-cloud-amd64 (SMP w/1 CPU core)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages apngdis depends on:
ii  libc6   2.28-10
ii  zlib1g  1:1.2.11.dfsg-1

apngdis recommends no packages.

Versions of packages apngdis suggests:
pn  apng2gif  <none>

-- no debconf information