Re: [GNU-linux-libre] Adding some scummvm game(s) to the "List of software that does not respect the Free System Distribution Guidelines".

[Denis 'GNUtoo' Carikli]

On Tue, 13 Jun 2023 21:01:43 +0200
Denis 'GNUtoo' Carikli <GNUtoo@cyberdimension.org> wrote:
> Here draci-historie has source code, and a cleaned up source zip,
> etc. 
> 
> Though we might need, starting from the source code, to find a way to
> run it in ScummVM to make sure that it has no nonfree dependencies
> (like nonfree compilers, nonfree tools to make an image that runs in
> ScummVM, etc).
I've looked a bit more into it, and there is some documentation (also
included in doc/ in its source code) that explains how to compile the
game[1]. I tried quickly to compile it but I failed. But I found 2
potential issues:
- The game is GPLv2 but I'm unsure if we have a license or not for the
  game data.
- Running modified versions of the game requires recompiling ScummVM[2].

So the good news is if that someone manages to verify that
draci-historie is really free and compile it, we also have the means to
patch scummVM to reject nonfree games.

On Guix it would be easy to build draci-historie as a dependency of
ScummVM, calculate its checksum and patch scummVM accordingly when
building ScummVM. 

For the other GNU/Linux distributions a way to do something like
that would be to build the games and ScummVM in the same source
package, and split the output to have ScummVM be a a dependency of
games. Distributions like Guix probably have/had wrappers for the games
I mentioned, so we could also use similar wrappers not to show ScummVM
too much in other distributions too.

This way could also probably work for a lot of emulators since many
of them have checksums of games in them. Some probably have some ways to
bypass the checksums through some command line options or settings
though.

If someone can confirm that the license of the data is OK, I can share
my unfinished initial package attempt.

All that also shows that we need to be cautious with some of the
software we package (especially emulators and VMs) as in cases like that
we can't really assume that things are OK just because there is some GPL
source code available.

References:
-----------
[1]https://www.ucw.cz/draci-historie/src/doc/compiling-the-game.txt
[2]From "4. Play the recompiled game": "[ScummVM] needs to know the MD5
   checksum of the new files to be able to detect the game. [explanation
   on how to patch ScummVM]"

Denis.

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