Using system2() to call git on Windows leads to issue

[cderv]

I think this is a limitation of using command line tool to deal with git instead of packages like gert

xfun::crandalf_check() will run command git() which is basically system2('git', ...).
Unfortunately, on Windows this lead to issues.
For example:

> xfun:::git(c('merge', 'main'))
Committer identity unknown

*** Please tell me who you are.

Run

  git config --global user.email "you@example.com"
  git config --global user.name "Your Name"

to set your account's default identity.
Omit --global to set the identity only in this repository.

However, I am set up

❯ git config user.name
Christophe Dervieux
❯ git config user.email
christophe.dervieux@gmail.com

I think this is because of the working directory ~ not being the same while I run git in terminal or run it through R command to call system tool.

When using system2(), it will look for global config file in C:/Users/chris/Documents/.gitconfig, whereas the file is in C:/Users/chris/.gitconfig which is where command line Git use. This is probably because of R - IDK.

Using special tool like gert or git2r does not have this issues, because they use a lib (C or C++ probably) and it does not have this issue.

Anyway, opening this issue so that this limitation is documented. I'll find a workaround or use Linux, until I find a solution to this if any.

[yihui]

Perhaps temporarily changing HOME to USERPROFILE can fix it. That is,

env = xfun::set_envvar(c(HOME = Sys.getenv('USERPROFILE'))
on.exit(xfun::set_envvar(env))

I don't know why R adds Documents after the HOME variable.

[cderv]

I'll try that.

But this is a another specificity of Windows where ~ does not mean the same thing between OS in R.

I remember a discussion on this, but I can't find it yet. I know this is really painful.

Basically

> Sys.getenv("R_USER")
[1] "C:\\Users\\chris\\Documents"
> Sys.getenv("HOME")
[1] "C:\\Users\\chris\\Documents"

https://cran.r-project.org/bin/windows/base/rw-FAQ.html#What-are-HOME-and-working-directories_003f

This is how the default is set. I can probably modify that as you suggest

[yihui]

That's interesting. I have never realized this difference until today. Anyway, xfun:::git() was just a quick and simple wrapper function that I didn't expect to be widely used by others, and obviously I've never tested it on Windows (so thanks for testing it!).

[cderv]

Oh yeah I know it was a quick wrapper untested :) You just happen to have a teammate using Windows 😅

That is to avoid this differences between OS that something tools using other generic lib are safer (like gert or git2r) as not using the CLI tool. Also that is to make things on the same level for all OS that fs has been done I think (in fs, ~ means USERPROFILE on Windows too).

I'll make the adaptation so that I can use the tooling for our team. I don't think this will be widely use by others so we'll continue adapt as needed I guess.

[cderv]

I have pushed a fix in yihui/xfun@7e511f6

> system2('git', c('config', 'user.name'), stdout = TRUE)
character(0)
attr(,"status")
[1] 1
Warning message:
In system2("git", c("config", "user.name"), stdout = TRUE) :
  running command '"git" config user.name' had status 1

> xfun:::git(c('config', 'user.name'))
Christophe Dervieux

So that should prevent error for me from now on.

[yihui]

Thanks!