[R] install_github broken for dependencies on packages previously installed from private github repo.

[Duncan Murdoch]

You posted this identical question to 
https://stackoverflow.com/q/57206597/2554330, and didn't fix it based on 
the comment asking for a reproducible example.  Please don't crosspost.

On 25/07/2019 3:15 p.m., Mark Mendel wrote:
> When installing from a private repo, fails if the package depends on
> another package from the private repo--even if its already installed.
> Example makes this clear
> 
> ```R
> install_github('MyAcct/Preinstalled.Package', auth_token = 'x')
> # works
> install_github('MyAcct/My.Package', auth_token = 'x', upgrade = FALSE)
> # Fails if My.Package depends on Preinstalled.Package -- see below
> ```
> I get the following errors.
> ```
> Downloading GitHub repo MyAcct/My.Package using master
> Error: HTTP error 404.
>    Not Found
> 
>    Did you spell the repo owner (`MyAcct`) and repo name
> (`Preinstalled.Package`) correctly?
>    - If spelling is correct, check that you have the required permissions to
> access the repo.
> ```
> 
> Why is it even checking the repo, since the package is already installed?
> 
> This used to work under the old devtools::install_github implementation,
> but that is now an alias for remotes::install_gitub
> 
> Using R 3.6.0
>