CRAN Repository Policy

Preamble

This document describes the policies in place for the R package repository hosted by the Comprehensive R Archive Network. In what follows, this CRAN package repository will be referred to as “CRAN”.

CRAN is maintained by the efforts of volunteers (the “CRAN team”) and the resources of the R Foundation and the employers of those volunteers (WU Wien, TU Dortmund, U Oxford, AT&T Research). Having a package distributed by CRAN is subject to a set of policies, and submitting a package (including an update) to CRAN indicates agreement to these policies.

Distributing code or documentation is subject to legal requirements, and CRAN operates in many jurisdictions. One of the aims of these policies is to ensure that the distributors meet their legal obligations of diligence without excessive work.

The time of the volunteers is CRAN's most precious resource, and they reserve the right to remove or modify packages on CRAN without notice or explanation (although notification will usually be given).

Source packages

• The ownership of copyright and intellectual property rights of all components of the package must be clear and unambiguous (including from the authors specification in the DESCRIPTION file). Where code is copied (or derived) from the work of others (including from R itself), care must be taken that any copyright/license statements are preserved and authorship is not misrepresented.

  Where copyrights are held by an entity other than the authors, the Authors@R field can be used, or a Copyright field (if necessary referring to an inst/COPYRIGHTS file).

  Trademarks must be respected.

• The package's DESCRIPTION file must show both the name and email address of a single designated maintainer (not a mailing list). That contact address must be kept up to date, and be usable for information mailed by the CRAN team without any form of filtering, confirmation ...

  The maintainer warrants that (s)he is acting on behalf of all credited authors and has their agreement to use their material in the way it is included in the package (or if this is not possible, warrants that it is used in accordance with the license granted by the original author).

  Additional DESCRIPTION fields could be used for providing email addresses for contacting the package authors/developers (e.g., ‘Contact’), or a URL for submitting bug reports (e.g., ‘BugReports’).

• Source packages may not contain any form of binary executable code.
• Source packages under an Open Source license must provide source or something which can easily be converted back to source (e.g., .rda files) for all components of the package (including for example PDF documentation and configure files produced by autoconf).

  Such packages are not permitted to require (e.g., by specifying in ‘Depends’, ‘Imports’ or ‘LinkingTo’ fields) directly or indirectly a package or external software which restricts users or usage.

  The package's license must give the right for CRAN to distribute the package in perpetuity. Any change to a package's license must be highlighted when an update is submitted (for there have been instances of an undocumented license change removing even the right of CRAN to distribute the package).

• Package authors should make all reasonable efforts to provide cross-platform portable code. Packages will not normally be accepted that do not run on at least two of the major R platforms. Cases for Windows-only packages will be considered, but CRAN may not be the most appropriate place to host them.
• Packages should be named in a way that does not conflict (irrespective of case) with any current or past CRAN package (the Archive area can be consulted), nor any current Bioconductor package. Package maintainers give the right to use that package name to CRAN when they submit, so the CRAN team may orphan a package and allow another maintainer to take it over.

  When a new maintainer wishes to take over a package, this should be accompanied by the written agreement of the previous maintainer (unless the package has been formally orphaned).

• Packages will not normally be removed from CRAN: however, they may be archived, including at the maintainer's request.

  Packages for which R CMD check gives an ‘ERROR’ when a new R x.y.0 version is released will be archived (or in exceptional circumstances updated by the CRAN team) unless the maintainer has set a firm deadline for an upcoming update (and keeps to it).

  Maintainers will be asked to update packages which show any warnings or significant notes, especially at around the time of a new x.y.0 release. Packages which are not updated are liable to be archived.

• Packages should be of the minimum necessary size. Reasonable compression should be used for data (not just .rda files) and PDF documentation: CRAN will if necessary pass the latter through qpdf.

  As a general rule, neither data nor documentation should exceed 5MB (which covers several books). A CRAN package is not an appropriate way to distribute course notes, and authors will be asked to trim their documentation to a maximum of 5MB.

  Where a large amount of data is required (even after compression), consideration should be given to a separate data-only package which can be updated only rarely (since older versions of packages are archived in perpetuity).

  Similar considerations apply to other forms of “data”, e.g., jar files.

• Checking the package should take as little CPU time as possible, as the CRAN check farm is a very limited resource and there are thousands of packages. Long-running tests and vignette code can be made optional for checking, but do ensure that the checks that are left do exercise all the features of the package.

  If running a package uses multiple threads/cores it must never use more than two simultaneously: the check farm is a shared resource and will typically be running many checks simultaneously.

  Examples should run for no more than a few seconds each: they are intended to exemplify to the would-be user how to use the functions in the package.

• The code and examples provided in a package should never do anything which might be regarded as malicious or anti-social. The following are illustrative examples from past experience.
  • Compiled code should never terminate the R process within which it is running. Thus C/C++ calls to assert/abort/exit, Fortran calls to STOP and so on must be avoided. Nor may R code call q().
  • A package must not tamper with the code already loaded into R: any attempt to change code in the standard and recommended packages which ship with R is prohibited. Altering the namespace of another package should only be done with the agreement of the maintainer of that package.
  • Packages should not write in the users' home filespace, nor anywhere else on the file system apart from the R session's temporary directory (or during installation in the location pointed to by TMPDIR: and such usage should be cleaned up). Installing into the system's R installation (e.g., scripts to its bin directory) is not allowed.

    Limited exceptions may be allowed in interactive sessions if the package obtains confirmation from the user.

  • Packages should not modify the global environment (user's workspace).
  • Packages should not start external software (such as PDF viewers or browsers) during examples or tests unless that specific instance of the software is explicitly closed afterwards.
  • Packages should not send information about the R session to the maintainer's or third-party sites without obtaining confirmation from the user.
  • Packages must not disable the stack-checking mechanism in the R process into which they are loaded.
  • CRAN packages should use only the public API. Hence they should not use entry points not declared as API in installed headers nor .Internal() nor .Call() etc calls to base packages. Such usages can cause packages to break at any time, even in patched versions of R.

Binary packages

Policies for when a (Windows or OS X) binary package will be distributed:

• all its package dependencies on CRAN are available for that platform. Dependencies from other repositories will be installed at CRAN's discretion.
• any external software needed can easily be installed on the build machine for all the sub-architectures: here “easily” includes not depending on specific versions, nor should the installed binary depend on specific versions.
• it passes R CMD check without error for all the available sub-architectures, or at CRAN's discretion, for the most important sub-architecture(s).

Binary packages are not accepted from maintainers: CRAN will only host binary packages prepared by those responsible for the binary areas. Their packages are made automatically by batch jobs and can take a day or two to appear on the CRAN master site (maybe longer to reach CRAN mirrors).

Submission

When submitting a package to CRAN you should either

• use the submission form at http://CRAN.R-project.org/submit.html, or
• upload by anonymous ftp to ftp://CRAN.R-project.org/incoming/ and send a (plain text ASCII) email at the same time, with subject line as specified below.

In more detail:

• Uploads must be source tarballs as created by R CMD build and follow the PACKAGE_VERSION.tar.gz naming scheme.
• Please ensure that R CMD check --as-cran has been run on the tarball to be uploaded before submission. This should be done with the current release of R or (preferably) R-devel or R-patched. As “Writing R Extensions” used to say

  Please ensure that you can run through the complete procedure with only warnings that you understand and have reasons not to eliminate. In principle, packages must pass R CMD check without warnings or significant notes to be admitted to the main CRAN package area. If there are warnings or notes you cannot eliminate (for example because you believe them to be spurious) send an explanatory note as part of your covering email.

• For a package update, please check that any packages depending on this one still pass R CMD check: it is especially expected that you will have checked your own packages. A listing of the reverse dependencies of the current version can be found on the CRAN web page for the package.
• A submission upload should be accompanied by an email to CRAN@R-project.org sent from the maintainer address listed in the package, and using the subject line `CRAN submission PACKAGE VERSION', where PACKAGE and VERSION are the package name and version, respectively. Plain text ASCII emails should be used if at all possible.

  If for some reason the submission has to be made by someone else (for example, a co-author) this needs to be explained, and the designated maintainer will need to confirm the submission. Explain any change in the maintainer's email address.

  For a new submission, confirm in your email that you have read and agree to these policies. (This includes new versions of previously archived packages, and the first submission as the new maintainer for a package.)

  If the package needs special treatment (for example if vignettes can only be run or re-built on the maintainer's machine or take a very long time), say so in the submission email.

  Do not email the package itself.

• Once uploaded, no further submissions of that package should be made whilst the uploaded version is pending processing (which may take a few days) and you have not received a reply from a CRAN maintainer.
• Part of the processing is that uploads may be renamed by adding one of the extensions .save, .pending or .noemail: the presence of such a file is a sign that the submission process is not finished yet and CRAN maintainers are waiting for response or resubmission from the package maintainer (and such a file name should never be uploaded).
• Submitting updates should be done responsibly and with respect for the volunteers' time. Once a package is established (which may take several rounds), “no more than every 1–2 months” seems appropriate.

  Authors can avoid a lot of the all too frequent rounds of updates by checking carefully for themselves. It should be normal for those without Windows machines of their own to use the winbuilder service to check a package before submission. There is a lot of helpful advice on writing portable packages in “Writing R Extensions”.

• If an update will change the package's API and hence affect packages depending on it, it is expected that you will contact the maintainers of affected packages and suggest changes, and give them time to prepare updates before submitting your updated package. Do mention in the submission email which packages are affected and that their maintainers have been informed. In order to derive the reverse dependencies of a package including the addresses of maintainers who have to be notified upon changes, the function reverse_dependencies_with_maintainers is available from the developer website.