Afero is a package that lets you mock out a filesystem with an in-memory filesystem.
It allows us to easily create the files required for a given test without worrying about
a cleanup step or different tests tripping on eachother when run in parallel.
Later on I'll standardise on using afero over the vanilla os package
There are quite a few paths you might want to get e.g. the repo's path, the worktree's path,
the repo's git dir path, the worktree's git dir path. I want these all obtained once and
then used when needed rather than having to have IO whenever we need them. This is not so
much about reducing time spent on IO as it is about not having to care about errors every time
we want a path.
By constructing an arg vector manually, we no longer need to quote arguments
Mandate that args must be passed when building a command
Now you need to provide an args array when building a command.
There are a handful of places where we need to deal with a string,
such as with user-defined custom commands, and for those we now require
that at the callsite they use str.ToArgv to do that. I don't want
to provide a method out of the box for it because I want to discourage its
use.
For some reason we were invoking a command through a shell when amending a
commit, and I don't believe we needed to do that as there was nothing user-
supplied about the command. So I've switched to using a regular command out-
side the shell there
