Bug#1151153: retroarch-assets: FTBFS: make[1]: *** [Makefile:52: assets/ozone/png/icons/Nintendo - Game Boy Advance (e-Reader).png] Error 1

[Simon McVittie]

Control: reassign -1 src:imagemagick
Control: affects -1 + src:retroarch-assets

On Sat, 17 Oct 2026 at 17:54:23 +0100, Jonathan McDowell wrote:
>On Sat, Oct 17, 2026 at 01:38:28PM +0000, Santiago Vila wrote:
>> During a rebuild of all packages in unstable, this package failed to build.
>
>I can reproduce this, and it appears to be as a result of a change in
>imagemagick; the actual failure is from a command like:
>
>$ magick mogrify -background 'rgb(255,255,255)' -alpha Background \
>	'assets/ozone/png/icons/APF - Imagination Machine.png'
>
>which results in:
>
>mogrify: no encode delegate for this image format `' @ warning/constitute.c/WriteImage/1473.
>mogrify: no encode delegate for this image format `' @ error/constitute.c/WriteImage/1482.

A small reproducer appears to be:

# apt install debconf imagemagick
$ cp /usr/share/pixmaps/debian-logo.png tmp.png
$ mogrify -debug all tmp.png

which worked in trixie (it's a no-op, it loads the image and saves it 
again), but not in sid. This isn't PNG-specific, the same thing for 
debian-logo.bmp also fails.

In the debug output, this looks fine:

2026-10-17T18:42:26+00:00 0:00.001 0.000u 7.1.2 Module mogrify[1658]: module.c/OpenModule/1281/Module
   Searching for module "PNG" using filename "png.la"
2026-10-17T18:42:26+00:00 0:00.001 0.000u 7.1.2 Module mogrify[1658]: module.c/GetMagickModulePath/560/Module
   Searching for coder module file "png.la" ...

but, later, this looks suspicious:

2026-10-17T18:42:26+00:00 0:00.004 0.000u 7.1.2 Coder mogrify[1658]: png.c/ReadPNGImage/4029/Coder
   exit ReadPNGImage()
2026-10-17T18:42:26+00:00 0:00.005 0.000u 7.1.2 Policy mogrify[1658]: policy.c/IsRightsAuthorizedByName/826/Policy
   Domain: Module; name: undefined; rights=Unrecognized; pattern="PNG-43B842CE~"; ...
2026-10-17T18:42:26+00:00 0:00.005 0.000u 7.1.2 Policy mogrify[1658]: policy.c/IsRightsAuthorizedByName/955/Policy
     authorized: true
2026-10-17T18:42:26+00:00 0:00.005 0.000u 7.1.2 Module mogrify[1658]: module.c/OpenModule/1281/Module
   Searching for module "PNG-43B842CE~" using filename "png-43b842ce~.la"
2026-10-17T18:42:26+00:00 0:00.005 0.000u 7.1.2 Module mogrify[1658]: module.c/GetMagickModulePath/560/Module
   Searching for coder module file "png-43b842ce~.la" ...

It looks like mogrify has somehow appended extra junk to the file 
format? A similar thing happens for the .bmp.

For retroarch-assets, it seems that it would probably be possible to 
work around this by using `magick convert ... in.png out.png`, instead 
of editing the same file in-place with mogrify.

     smcv