Libpng12-0: Something happened between Cosmic and Disco

Support & Help Requests
#1

I encountered this error earlier, and while you may think this is a duplicate, this is an entirely new error I don't think anyone else has written about.

So get this, when I try to install the software in question I get this;

Get:1 [...]/libpng12-0_1.2.54-1ubuntu1_i386.deb libpng12-0 i386 1.2.54-1ubuntu1 [122 kB]
(Reading database ... 429607 files and directories currently installed.)
Preparing to unpack .../libpng12-0_1.2.54-1ubuntu1_i386.deb ...
Unpacking libpng12-0:i386 (1.2.54-1ubuntu1) ...
dpkg: error processing archive [...]/libpng12-0_1.2.54-1ubuntu1_i386.deb (--unpack):
 unable to install new version of '/usr/lib/i386-linux-gnu/libpng12.so.0': No such file or directory
No apport report written because the error message indicates an issue on the local system
                                                                                         Errors were encountered while processing:
 [...]/libpng12-0_1.2.54-1ubuntu1_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

Why? I need this for a piece of software known as zsnes and I prefer to use version 1.42.

#2

Yeah, I tried to install it and failed. Perhaps this may help in installing your file.

https://ubuntu.pkgs.org/16.04/ubuntu-main-i386/libpng12-0_1.2.54-1ubuntu1_i386.deb.html

Good luck tiox.

#3

I believe I had already tried that. Will see if libpng16 needs to be removed first.

#4

I can reproduce the problem using package from xenial-updates even on minimal 19.10 system

cd ~/Downloads
wget http://mirrors.kernel.org/ubuntu/pool/main/libp/libpng/libpng12-0_1.2.54-1ubuntu1.1_i386.deb
sudo apt install ./libpng12-0_1.2.54-1ubuntu1.1_i386.deb

it ends with

Unpacking libpng12-0:i386 (1.2.54-1ubuntu1.1) ...
dpkg: error processing archive /tmp/apt-dpkg-install-GceDPS/6-libpng12-0_1.2.54-1ubuntu1.1_i386.deb (--unpack):
 unable to install new version of '/lib/i386-linux-gnu/libpng12.so.0': No such file or directory
Errors were encountered while processing:
 /tmp/apt-dpkg-install-GceDPS/6-libpng12-0_1.2.54-1ubuntu1.1_i386.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

So I would suggest to use Ubuntu MATE 18.04 LTS for serious work and gaming :slight_smile:
Libpng 1.2 installs here normally.

1 Like
#5

Hey guys I figured it out~

...At least, for my use case. So right, I made a fake i386 package of a higher version according to apt in Ubuntu MATE 18.04.3 i386 using equivs with the control file from libpng12-0_1.2.54-1ubuntu1_i386.deb obtainable from Ubuntu Packages for Xenial as a base.

After making this fake package with no library files in it, I installed it in Ubuntu MATE 19.10, then while installing zsnes_1.420-2ubuntu1_i386.deb that package pulled in every other 32-bit dependency it needed.

I tried symlinking the 64-bit libpng16-0 files into the 32-bit directory but it turned out to be the incorrect ELF class (no surprises there, thought I was being clever) but after copying i386-linux-gnu/ from libpng12-0_1.2.54-1ubuntu1_i386.deb into /usr/lib/ everything worked.

So what now?

I believe for a proper resolution to this issue, the original libpng12-0 package from xenial needs a repack with a control file that doesn't make apt fly off the handle about installing it. My method is supremely cludgy but I will leave it to someone else to build a proper package for it.

1 Like
#6

As the title alludes to, something did indeed happen between these two revisions. The jump from 18.04 to 18.10 added something apt doesn't like when it attempts to install libpng12.0:i386. Could it be, this is when libpng16:amd64 was introduced, and that's truly the conflict at hand here?

In the control file for libpng12-0:i386 (Canonical's copy from Ubuntu Xenial) this is what's in its control file:

Conflicts: libpng12-dev (<= 1.2.8rel-7), mzscheme (<= 1:209-5), pngcrush (<= 1.5.10-2), pngmeta (<= 1.11-3), povray-3.5 (<= 3.5.0c-10), qemacs (<= 0.3.1-5)
Replaces: libpng12-dev (<= 1.2.8rel-7)

But that's saying the conflict is for any version of libpng12-dev and the offending library I theorize may be the issue is libpng16-16. That shouldn't be a problem.

So what's really going on here?