libzxing3 tries to clobber libzxing2 library file on KDE neon Ubuntu spin

[Gabriel A. Devenyi]

Running the latest (KDE Neon on Ubuntu 22.04 from https://neon.kde.org/download, an alternative KDE to Kubuntu on Ubuntu)

Trying to install gstreamer1.0-plugins-bad pulls in libzxing3, which tries to clobber an existing package's files:

dpkg: error processing archive /var/cache/apt/archives/libzxing3_2.2.1-3~22.04.sav1_amd64.deb (--unpack):
 trying to overwrite '/usr/lib/x86_64-linux-gnu/libZXing.so.3', which is also in package libzxing2:amd64 2.1.0-0xneon+22.04+jammy+release+build8

the libzxing2 library file is provided from a KDE Neon ubuntu package:
Package: libzxing2
Priority: optional
Section: libs
Installed-Size: 1183
Maintainer: Neon CI <email address hidden>
Architecture: amd64
Source: zxing-cpp
Version: 2.0.0-0xneon+22.04+jammy+release+build7
Depends: libc6 (>= 2.34), libgcc-s1 (>= 3.4), libstdc++6 (>= 11)
Filename: pool/main/z/zxing-cpp/libzxing2_2.0.0-0xneon+22.04+jammy+release+build7_amd64.deb
Size: 496424
MD5sum: bf2792e869be1e6d78a64518f998ffcc
SHA1: 824ec57a9cacb2492aa3cff952302407443911fe
SHA256: c3d58c9684410ab64acd948b8acdc5272a59935fd671e440adb4d7a72dcc5eca
SHA512: a28f73850d2f6f99de94cd0d32bc86a09f7924a2f9f649ef8b00a572cb7f669f536bef4b9dd373adb7eb418dba003e2dd11a1d7a8ea34e2f69bb93d1df2948a8
Description: C++ port of ZXing library (library files)
 ZXing-C++ ("zebra crossing") is an open-source, multi-format 1D/2D
 barcode image processing library implemented in C++.
 .
 It was originally ported from the Java ZXing library but has been
 developed further and now includes many improvements in terms of
 quality and performance. It can both read and write barcodes in a
 number of formats: QR Code, DataMatrix, Aztec, PDF417, UPC-A, UPC-E,
 EAN-8, EAN-13, DataBar/RSS, Code 39, Code 93, Code 128, Codabar, ITF.
 .
 This package provides library files for zxing-cpp library.
Description-md5: 0fac22bb00ceb14fd52df59bb518c40d
Multi-Arch: same
Homepage: https://github.com/zxing-cpp/zxing-cpp

[Gabriel A. Devenyi (gadevenyi)]

From the KDE Neon ppa overlay:
deb http://archive.neon.kde.org/user jammy main

[Rob Savoury (savoury1)]

If the output you have quoted is correct then the libzxing2:amd64 2.1.0-0xneon+22.04+jammy+release+build8 package has not followed Debian/Ubuntu policy. Note that you quoted a different package version in your explanation (the one I've mentioned above) than in the copy/pasted package output, which is for 2.0.0-0xneon+22.04+jammy+release+build7.

This is a bug with the KDE Neon package and you should report the issue there. There is no bug in the package at my PPA, almost all packages at my PPAs are simply backports (with changes as required to make it build on older series). This means that I am in almost all cases simply "inheriting" exactly the Debian/Ubuntu packaging, such as the correct library names based on specific SONAME/SOVERSION details.

Where I do new packages that are not yet in Debian/Ubuntu (or upgrades to newer versions not yet in Debian/Ubuntu) I closely adhere to the same guidelines as for all official Debian/Ubuntu packages. That is to avoid exactly this type of issue.

With the KDE Neon package there should have been a SONAME bump, ie. a new binary package libzxing3 (not libzxing2) containing the updated libZXing.so.2.1.0 library. They didn't do this, and so it is conflicting with the correctly named package at my PPA. It would also conflict with any official Debian/Ubuntu version of src:zxing-cpp >= 2.1.0 which can be confirmed on Debian's website [*] in their own changelog.

Note the entry: "debian/: Bump library SONAME to 3."

[*] https://tracker.debian.org/news/1472895/accepted-zxing-cpp-210-1-source-amd64-all-into-experimental/

[Gabriel A. Devenyi (gadevenyi)]

Thanks very much, that's very clear. I'll upstream this bug to neon.

[Gabriel A. Devenyi (gadevenyi)]

https://bugs.kde.org/show_bug.cgi?id=482472