pnginfo(1) never prints any text strings

[Brian Foster]

In 20.04 (focal), pnginfo would print any text strings (or tag/values) present in a PNG image metadata.
In 22.04 (jammy), pnginfo always claims there are "0 of 0" text strings and never prints any.

Attached is a script which shows the problem, and the results from both 20.04 and 22.04 (the diff of the two results is slightly messy, I've redacted not-relevant details to improve the diff).

Whilst any PNG image can be used to test, the script generates an image using qrencode(1). The visual image itself is not-relevant, the problem is pnginfo's non-interpretation of the metadata in the .png image file.

(From comment #3.) Most of the script is concerned with faffing around and obtaining versioning information, etc.
The key part of the script is (this works standalone):

   qrencode --output=FILE.png -- "stuff"
   exiftool -Description="Hello, world!" FILE.png
   pngmeta --all -- FILE.png
   pnginfo FILE.png

Notice that in the resultant output, on 22.04 (jammy), whist pngmeta(1) prints the "Description" tag, pnginfo(1) does not, claiming there are "0 of 0" text strings.

The script itself actually adds multiple tags, all of which are printed by pngmeta but (no longer) by pnginfo.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: pngtools 0.5~git20120106.409eb16-1
ProcVersionSignature: Ubuntu 5.15.0-47.51-generic 5.15.46
Uname: Linux 5.15.0-47-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: KDE
Date: Thu Sep 15 17:10:28 2022
InstallationDate: Installed on 2020-10-19 (696 days ago)
InstallationMedia: Kubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
SourcePackage: pngtools
UpgradeStatus: Upgraded to jammy on 2022-09-04 (10 days ago)

[Brian Foster (blfoster)]

(Grrrr... Adding attachments is annoying and causing comments to vanish!)

Most of the script is concerned with faffing around and obtaining versioning information, etc.
The key part of the script is (this works standalone):

   qrencode --output=FILE.png -- "stuff"
   exiftool -Description="Hello, world!" FILE.png
   pngmeta --all -- FILE.png
   pnginfo FILE.png

Notice that in the resultant output, on 22.04 (jammy), whist pngmeta(1) prints the "Description" tag, pnginfo(1) does not, claiming there are "0 of 0" text strings.

The script itself actually adds multiple tags, all of which are printed by pngmeta but (no longer) by pnginfo.