install_github fails when using devtools 1.12.0 on R 3.1

[leonidb]

According to 1.12.0 description, R >= 3.0.2 is supported, however, when using devtools with R 3.1

devtools::install_github("...")

We get the following error:

    Downloading GitHub repo ...
    from URL ...
    Installing ...
    Error in if (capabilities("libcurl")) { : argument is of length zero
    Calls: <Anonymous> ... download_method_secure -> download_method -> auto_download_method

The check if (capabilities("libcurl")) was added in eed0746, which is part of 1.12.0 release.

When I execute capabilities(), libcurl indeed doesn't appear on the list, although
libcurl library is installed on the machine.

With devtools 1.11.1 the same command works.

[crarlus]

I can confirm this issue for R 3.1.

Error in if (capabilities("libcurl")) { : argument is of length zero

Apparently this arises in older versions of R.

In R 3.3

help("capabilities") 

states

libcurl 
is libcurl available in this build? Used by function curlGetHeaders and optionally by download.file and url. As from R 3.3.0 always true for Unix-alikes, and true for CRAN Windows builds.

The entry for libcurl is missing in older versions of R.

Furthermore, in https://cran.r-project.org/doc/manuals/r-release/NEWS.html it was announced

CHANGES IN R 3.2.0
    ...
    capabilities("libcurl") reports if this is available.

Hence, in file download-method.R one needs to check if the entry for "libcurl" exists at all, e.g.

any(names(capabilities()) == "libcurl")

[damesek]

These lines solved this problem at my case:

sudo apt-get install libcurl4-openssl-dev libxml2-dev libxslt-dev libssl-dev -y
sudo apt-get install r-base r-base-dev -y

(ubuntu 14.04)

[vext01]

The workaround I used is:
> options(download.file.method = "wget")