[Question] Support for Mono

[gep13]

Does GitVersion support running under Mono?

If not, are there any plans to support?

[JakeGinnivan]

The issue is libgit2 and libgit2sharp. It would have to ship different versions of the native library to work on different operating systems afaik.

I seem to remember there being a thread about this. @nulltoken can probably tell you more

[gep13]

Ah, good point. I have never built anything targeted at Mono, so wouldn't know where to start conditionally compiling the included DLL's depending on the target. Doesn't seem like it should be outwith the realm of possibility though.

[nulltoken]

@gep13 Well, LibGit2Sharp actually runs on Mono. But, currently, this requires the user to build his/her own version of libgit2 (See https://github.com/libgit2/libgit2sharp/blob/vNext/build.libgit2sharp.sh).

@Therzok is maintaining a repo for Windows and Mac versions of libgit2 at https://github.com/mono/libgit-binary

However, I'm not sure how many versions of the compiled binaries we should maintain for other *nix plaforms (@carlosmn @ethomson Thoughts?)

[Therzok]

I think it's worth mentioning that my versions of the binaries support SSH.

[Therzok]

@nulltoken before you think I don't want to push the changes, it's because I haven't modeled a proper API for credentials. I've written some stubs which work. :P

[Therzok]

@nulltoken regarding how I build libgit2sharp inside MD.

For Windows and Mac I build libgit2sharp and copy the binaries to the output directory.
For Linux, I run a slightly modified version of the build.libgit2sharp.sh file to enable ssh. Grab the native binaries output directory and copy paste them.

[gep13]

So, as a noob to this sort of thing, let's say I wanted to run GitVersion, using Mono, on an Ubuntu machine. What would be the process for getting this done?

• Ensure that everything in GitVersion itself is Mono Compliant
• Build LibGit2 on an Ubuntu Distro
• Take the compiled DLL's and build LibGit2Sharp
• Take both DLL's and reference them in GitVersion
• Run the resulting exe on Ubuntu using mono

Is that about right? Or am I completely off?

[Therzok]

Make sure the libgit2 native livrary binaries are side-by-side with the libgit2sharp DLLs so you don't have to mess with library resolver path settings. Otherwise, it lgtm.

[carlosmn]

@Therzok is this same-directory loading a mono extension? The documentation suggests that it simply delegates to dlopen(3) which won't do that unless you have '.' in LD_LIBRARY_PATH or the rpath option is given to the linker, which won't happen by default.

@nulltoken the binaries shouldn't be in kept in the repo, and there's too many variations to reasonably keep them in a single place.

The way to distribute binary libraries on unix is to make use of the package manager for a particular OS of family which can depend on the zlib, openssl, libssh2 and http-parser packages. Otherwise you're either going to have to ship a very limited version of libgit2 or field that kind of support requests.

[Therzok]

@carlosmn the way I implemented it in MD is without adding the libgit2 path to LD_LIBRARY_PATH. I have used install_name_tool on the native binaries to use @loader_path, maybe that's why it works. :P

[Therzok]

otool -L libgit2-69db893.dylib

libgit2-69db893.dylib:
    libgit2-69db893.dylib (compatibility version 21.0.0, current version 0.21.0)
    /usr/lib/libz.1.dylib (compatibility version 1.0.0, current version 1.2.5)
    /usr/lib/libssl.0.9.8.dylib (compatibility version 0.9.8, current version 50.0.0)
    /usr/lib/libcrypto.0.9.8.dylib (compatibility version 0.9.8, current version 50.0.0)
    @loader_path/libssh2.dylib (compatibility version 2.0.0, current version 2.1.0)
    /usr/lib/libiconv.2.dylib (compatibility version 7.0.0, current version 7.0.0)
    /usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 1197.1.1)

[Therzok]

The sequence of commands I've used in this was:
install_name_tool -id libgit2-69db893.dylib libgit2-69db893.dylib
install_name_tool -change <absolute_path_to_libssh2> @loader_path/libssh2.dylib

[Therzok]

@carlosmn but on Linux it should justwork™. Linux user reported it worked without any extra effort if the libgit2 binaries are side-by-side with the libgit2sharp dlls.

[carlosmn]

That shows how you can ship the dependencies of libgit2, but not how mono/LibGit2Sharp.dll knows to load libgit2-abcd.so from the current directory, since doing this should precisely not work unless you take extra steps. Do you have a LibGit2Sharp.dll.config file that lets you do that?

[Therzok]

Simply setting -id to the filename works.