Roel Janssen <roel@gnu.org> writes:

> Roel Janssen <roel@gnu.org> writes:
>
>> Mark H Weaver <mhw@netris.org> writes:
>>
>>> Hello Guix,
>>>
>>> Below I've attached a draft patch to update vlc to 3.0.1, and also to
>>> add several more inputs based on reading the output of the 'configure'
>>> script.
>>>
>>> It builds successfully and mostly works except for one problem: the
>>> icons are missing from the control buttons on the main window of the Qt
>>> interface.  The icons in question are .svg files in the source tarball,
>>> but are converted into data structures within C++ source code using
>>> 'rcc'.
>>>
>>> strace reveals that vlc is performing 'stat' system calls on bogus file
>>> names beginning with ":/", e.g. ":/toolbar/play_b.svg".  These
>>> correspond to the missing icons.  According to
>>> <https://doc.qt.io/archives/qt-4.8/resources.html>, these names that
>>> begin with ":/" are meant to be references to resources that were
>>> imported using 'rcc'.
>>>
>>> I can't afford to spend more time on this right now.  I don't use vlc
>>> myself, but for security reasons I think it's important to keep our
>>> media players up-to-date, especially media players like vlc that bundle
>>> their own codecs.  I expect that vlc is quite popular, which makes it
>>> all the more important.
>>>
>>> I'm hoping that someone with more knowledge of Qt will step up to debug
>>> this problem.  Any volunteers?
>>>
>>> Note, this patch is based on core-updates, but hopefully it would work
>>> on 'master' too.
>>
>> Thanks a lot for working on this!  I applied your patch to ‘master’ and
>> built VLC.  It is missing the icons.
>>
>> Then I manually built it inside a ‘guix environment vlc’.
>> Launching it shows the icons.  Leaving the environment and running the
>> same executable misses the icons.
>>
>> Could it be that we need to propagate an input?
>> I'll try to dissect it further.
>
> After setting QT_PLUGIN_PATH outside of the environment, the icons
> appear in the Guix-compiled vlc-3.0.1.  I think the files in
> QT_PLUGIN_PATH do not originate from VLC, but instead from Qt and
> QtSvg.
>
> Should we wrap the executable so that QT_PLUGIN_PATH is defined?

The attached patch adds such a wrap phase, with which running ‘vlc’ the
icons work again.

Kind regards,
Roel Janssen