# 4 The DESCRIPTION file

The DESCRIPTION file must be properly formatted. The following sections will review some important notes regarding fields of the DESCRIPTION file and associated files.

## 4.1Package

This is the name of the package.

## 4.2Title

This is a brief but descriptive title for the package.

## 4.3Version

All Bioconductor packages use an x.y.z version scheme. See Version Numbering for specifics to how the release and devel Bioconductor versioning proceeds. When first submitted to Bioconductor, a package should have pre-release version 0.99.0.

The following rules apply:

• x is usually 0 for packages that have not yet been released.
• y is even for packages in release, and odd for packages in devel. Generally, do not bump this number especially in pre-release.
• z is incremented whenever committing changes to a package.

## 4.4Description

The description should be a relatively short but detailed overview of what the package functionality entails. It should be at least three complete sentences.

## 4.5Authors@R

The Authors@R field should be used. A maintainer designation (cre for Authors@R) is required with an actively maintained email address. This email address will be used for contact regarding any issues that arise with the package in the future.

For persons with an ORCiD identifier provide the identifier via an element named “ORCID” in the comment argument of person().

person("Lori", "Shepherd",
email = Lori.Shepherd@roswellpark.org,
role = c("cre", "aut"),
comment = c(ORCID = "0000-0002-5910-4010"))

Only one person should be listed as the Maintainer to ensure a single point of contact. This person by default will have commit access to the git repository on git.bioconductor.org. Commit access can be given to other developers by request on the bioc-devel mailing list.

Another option is to add collaborators to the GitHub repository. This approach enables development by many but restricts push access to git.bioconductor.org.

## 4.6License

The license field should preferably refer to a standard license (see wikipedia) using one of ’s standard specifications.

Be specific about any version that applies (e.g., GPL-2). Licenses restricting use, e.g., to academic or non-profit researchers, are not suitable for Bioconductor. Core Bioconductor packages are typically licensed under Artistic-2.0.

To specify a non-standard license, include a file named LICENSE in your package (containing the full terms of your license) and use the string file LICENSE in this License: field.

The package should contain only code that can be redistributed according to the package license. Be aware of the licensing agreements for packages you are depending on in your package. Not all packages are open source even if they are publicly available.

## 4.7LazyData

For packages that include data, we recommend not including LazyData: TRUE. However, this rarely proves to be a good thing. In our experience it only slows down the loading of packages with large data.

## 4.8Depends, Imports, Suggests, Enhances

All packages must be available via Bioconductor’s biocViews or CRAN; the use of the Remotes: field is not supported, hence dependencies only available on other repositories (e.g.  GitHub) are not allowed.

Reuse, rather than re-implement or duplicate, well-tested functionality from other packages. Make use of appropriate existing packages (e.g., biomaRt, AnnotationDbi, Biostrings) and classes (e.g., SummarizedExperiment, GRanges, Rle, DNAStringSet), and avoid duplication of functionality available in other Bioconductor packages. See Common Bioconductor Methods and Classes. Bioconductor reviewers are very strict on this point! New packages should be interoperable with existing Bioconductor classes and should not reimplement functionality especially with regards to importing/reading data.

A package can be listed only once between Depends:, Imports:, Suggests:, or Enhances:. Determine placement of package based on the following guidelines:

• Imports: is for packages that provide functions, methods, or classes that are used inside your package name space. Most packages are listed here.

• Depends: is for packages that provide essential functionality for users of your package, e.g., the GenomicRanges package is listed in the Depends: field of GenomicAlignments. It is unusual for more than three packages to be listed as Depends:.

• Suggests: is for packages used in vignettes, examples, and in conditional code.Commonly, annotation and experiment packages (e.g., TxDb*) used in vignette and example code are included in this field thus avoiding a costly download. In the case where an external one-off function is required for package code, the package availability and usage can be done via:

if (!requireNamespace('suggPKG', quietly = TRUE))
stop("Install 'suggPKG' to use this function.")
suggPKG::function()
• Enhances: is for packages such as Rmpi or parallel that enhance the performance of your package, but are not strictly needed for its functionality.

It is seldom necessary to specify or specific versions as dependencies, since the Bioconductor release strategy and standard installation instructions guarantee these constraints. Repositories mirrored outside Bioconductor should include branches for each Bioconductor release, and may find it useful to fully specify versions to enforce constraints otherwise guaranteed by Bioconductor installation practices.

## 4.9SystemRequirements

This field is for listing any external software which is required, but not automatically installed by the normal package installation process.

If the installation process is non-trivial, a top-level INSTALL file should be included to document the process. If a user facing README is included it is also recommended to document the process there.

## 4.10biocViews

This field is required!

Specify at least two leaf node from biocViews. Multiple leaf terms are encouraged but terms must come from the same trunk or package type (i.e., Software, AnnotationData, ExperimentData, or Workflow).

## 4.11BugReports

It is encouraged to include the relevant links to GitHub for reporting issues.

## 4.12URL

This field directs users to source code repositories, additional help resources, etc; details are provided in the Writing R Extensions manual, RShowDoc("R-exts").

## 4.13Video

This field displays links to instructional videos.

## 4.14Collates

This may be necessary to order class and method definitions appropriately during package installation.

## 4.15BiocType

This is required if submitting a Docker or Workflow. Otherwise this field could optionally define the type of Bioconductor package Software, ExperimentData, Annotation.