Add --safe-directory flag

[sgriffith3]

Is your feature request related to a problem? Please describe.
My team has been struggling to get the newest release (0.3.12) to work inside of a Jenkins environment, that then launches the convco container with docker.

Running this command:

docker run -v "$PWD:/tmp" --workdir /tmp --rm convco

We have been seeing the error:

Error: Git(Error { code: -3, klass: 7, message: "config value 'safe.directory' was not found" })

While this would regularly be overcome easily with the command git config --add safe.directory *, this is unfortunately not an option for the docker container as far as we have figured out.

Describe the solution you'd like
I would like an easy way to add a safe-directory. I believe this could be achieved with convco updating the configuration of git, and therefore suggest adding an optional flag that would temporarily add a specified safe directory.

Describe alternatives you've considered
Our workaround to this was to create a gitconfig file, and mount that as a volume.

# gitconfig
[safe]
  directory=/tmp

Working command:
docker run --rm -v "$PWD:/tmp" -v "$PWD/gitconfig:/etc/gitconfig" -w /tmp convco version

Additional context
If this is not possible for the time being, a note in the README indicating this workaround would be nice.

[hdevalke]

I had to lookup what this safe directory is doing:

https://git-scm.com/docs/git-config/2.35.2#Documentation/git-config.txt-safedirectory
These config entries specify Git-tracked directories that are considered safe even if they are owned by someone other than the current user.

is it possible the directory /tmp is not owned by the user running docker (i guess root is running in your example, but the pwd is owned by the jenkins user? docker run -u "$(id -u):$(id -g)" -v "$PWD:/tmp" --workdir /tmp --rm convco could probably solve your issue as well.

The issue with * is probably related to libgit2/libgit2#6391.

[hdevalke]

#88 adds better error handling for this case.

If it occurs you will see this in the stderr output:

Error: Could not open the git repository.
If run from docker set the right user id and group id.
E.g. `docker run -u "$(id -u):$(id -g)" -v "$PWD:/tmp" --workdir /tmp --rm convco/convco`

Caused by:
    config value 'safe.directory' was not found; class=Config (7); code=NotFound (-3)