Inferring package sources

The following fields are checked, in order, when inferring a package’s source:

1. The RemoteType field; typically written for packages installed by the devtools, remotes and pak packages,

2. The Repository field; for example, packages retrieved from CRAN will typically have the Repository: CRAN field,

3. The biocViews field; typically present for packages installed from the Bioconductor repositories,

As a fallback, if renv is unable to determine a package’s source from the DESCRIPTION file directly, but a package of the same name is available in the active R repositories (as specified in getOption("repos")), then the package will be treated as though it was installed from an R package repository.

If all of the above methods fail, renv will finally check for a package available from the cellar. The package cellar is typically used as an escape hatch, for packages which do not have a well-defined remote source, or for packages which might not be remotely accessible from your machine.

Unknown sources

If renv is unable to infer a package’s source, it will inform you during renv::snapshot() – for example, if we attempted to snapshot a package called skeleton with no known source:

> renv::snapshot()
The following package(s) were installed from an unknown source:

        skeleton

renv may be unable to restore these packages in the future.
Consider reinstalling these packages from a known source (e.g. CRAN).

Do you want to proceed? [y/N]:

While you can still create a lockfile with such packages, restore() will likely fail unless you can ensure this package is installed through some other mechanism.

Custom R package repositories

Custom and local R package repositories are supported as well. The only requirement is that these repositories are set as part of the repos R option, and that these repositories are named. For example, you might use:

repos <- c(CRAN = "https://cloud.r-project.org", WORK = "https://work.example.org")
options(repos = repos)

to tell renv to work with both the official CRAN package repository, as well as a package repository you have hosted and set up in your work environment.

Bioconductor

renv has been designed to work together as seamlessly as possible with the Bioconductor project. This vignette outlines some of the extra steps that may be required when using renv with packages obtained from Bioconductor.

Initializing a project

To initialize renv in a project using Bioconductor, you can pass the bioconductor argument to renv::init():

# use the latest-available Bioconductor release
renv::init(bioconductor = TRUE)

# use a specific version of Bioconductor
renv::init(bioconductor = "3.14")

This will tell renv to activate the appropriate Bioconductor repositories, and to use those repositories when attempting to restore packages.

renv::settings$bioconductor.version("3.14")

options(renv.bioconductor.repos = c(...))

The package cellar

In some cases, your project may depend on R packages which are not available from any external source, or that external source may not be accessible from the machine calling renv::restore(). To help accommodate these scenarios, renv allows you to prepare a package “cellar”, to be used as an ad-hoc repository of packages during restore. This allows you to provide package tarballs that can be used to restore packages which cannot be retrieved from any other source.

The environment variable RENV_PATHS_CELLAR can be used to customize the package cellar location. It should point to a directory containing package binaries and sources, with a structure of the form:

• ${RENV_PATHS_CELLAR}/<package>_<version>.tar.gz; or
• ${RENV_PATHS_CELLAR}/<package>/<package>_<version>.tar.gz

Alternatively, you can also use a project-local cellar by placing your packages within a folder located at <project>/renv/cellar. Note that this folder does not exist by default; you must create it to opt-in.

• <project>/renv/cellar/<package>_<version>.tar.gz; or
• <project>/renv/cellar/<package>/<package>_<version>.tar.gz

As an example, if your project depended on a package skeleton 1.0.0, you could place a tarball for this package in one of the following locations:

• ${RENV_PATHS_CELLAR}/skeleton_1.0.0.tar.gz
• ${RENV_PATHS_CELLAR}/skeleton/skeleton_1.0.0.tar.gz
• <project>/renv/cellar/skeleton_1.0.0.tar.gz; or
• <project>/renv/cellar/skeleton/skeleton_1.0.0.tar.gz

Once this is done, renv will consult these directories during future attempts to restore your packages.

You can install a package from the cellar like any other package, i.e. renv::install("skeleton").

During restore, if a compatible package is located within the cellar, that copy of the package will be preferred even if that package might otherwise be accessible from its associated remote source. For example, if skeleton 1.0.0 was also available on CRAN, renv::restore() would still use the tarball available in the cellar rather than the version available from CRAN.

If you want to see what paths renv is using for the cellar, you can use:

renv:::renv_paths_cellar()

See ?paths for more details.

{
  "Package": "skeleton",
  "Version": "1.0.1",
  "Source": "/mnt/r/pkg/skeleton_1.0.1.tar.gz"
}

ABI compatibility

ABI compatibility issues can arise if different packages were built against different versions of a shared dependency. For example, one package may have been built against Rcpp 1.0.6, and another package might have been built against Rcpp 1.0.7. However, because only one version of the Rcpp package can be loaded at a time within an R session, mixing of these two packages might cause issues either on load or at runtime depending on the version of Rcpp available.

It’s worth emphasizing that this is not Rcpp’s fault; a package built against Rcpp 1.0.7 would reasonably expect newer APIs made available by that version of the package would be available at runtime, and that contract would be violated if an older version of Rcpp were installed in the project library. The challenge for renv is that this build-time dependency is not clearly communicated to renv; in general, it is not possible to know what packages (and their versions) a particular package was built against.

Build-time dependencies

R packages might occasionally (and unintentionally) take a build-time dependency on another R package – for example, a package with the code:

`%>%` <- magrittr::`%>%`

would take the version of %>% that was available from the version of magrittr that was available at build time, not the one available at run time. This could be problematic if, for example, an update to the magrittr package changed in a way that made old definitions of %>% incompatible with newer internal functions.

In general, it is a mistake for packages to take a build-time dependency on exported objects from another package; rather, such objects should be imported at runtime (using e.g. importFrom() in the package NAMESPACE file).