Fix mkbundle executable crash

[memchr]

In CKAN.GameInstance.PortableDir (CKAN.Games.IGame game):

            // Find the directory our executable is stored in.
            string exeDir = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);

An empty string would be assigned to exeDir when ckan is packaged
using mkbundle. This caused following method call
game.GameInFolder(new DirectoryInfo(exeDir)) to crash with
System.ArgumentException: The specified path is not of a legal form (empty).

mkbundle --deps -o ckan --simple --machine-config /etc/mono/4.5/machine.config --config /etc/mono/config --simple ckan.exe

[HebaruSan]

For anyone else who wasn't familiar with mkbundle, it generates "self-contained executables that do not rely on Mono being installed on the system to simplify deployment of .NET Applications":

• https://www.mono-project.com/docs/tools+libraries/tools/mkbundle/

That sounds potentially useful as an alternate download format. Though for this specific fix, it would be better if we could fall back to the path of the mkbundle-generated executable when the executing assembly path can't be found, so users could still put their native-compiled ckan executable in the game root.

@memchr, would you mind checking the size of the executables generated in this way? I'm not currently in a Mono environment.

[HebaruSan]

This might be the way to get the bundle path:

• https://stackoverflow.com/a/57649113/2422988

Path.GetDirectoryName(Process.GetCurrentProcess().MainModule.FileName)

EDIT: Confirmed, with this change I am able to place the native ckan executable in a game folder and the portable instance is detected. Commit pushed.

[memchr]

would you mind checking the size of the executables generated in this way? I'm not currently in a Mono environment.

Size of executable generated with mono 6.12.0.177 on Linux is 36.1 MB

[HebaruSan]

Thanks! That's surprisingly reasonable compared to other modern day downloads (even if it's much larger than ckan.exe by itself). Bigger than Python, smaller than VLC or Git. This might make a nice middle ground between the current downloads and the full-on bloat packaging requested in #2636.

[HebaruSan]

What command line are you using to build? My Ubuntu VM is giving me an error related to I18N.dll, but if you've already got it building enough to crash, maybe you already know the solution to this?

$ mkbundle --deps ckan.exe
Failure to load i18n assemblies, the following directories were searched for the assemblies:
   Path: .
In Custom mode, you need to provide the directory to lookup assemblies from using -L
ERROR: Couldn't load one or more of the i18n assemblies: Failed to load I18N.dll

[memchr]

The command i am using is:

mkbundle --deps -o ckan --simple --machine-config /etc/mono/4.5/machine.config --config /etc/mono/config --simple ckan.exe

However this may not work on Ubuntu as I only tested it on Arch.
You may need to change path of --machine-config and --config

[HebaruSan]

Thanks, that also worked on Ubuntu. 🎉

[HebaruSan]

Thanks for improving compatibility with mkbundle!