desc

Parse DESCRIPTION files

Parse, manipulate and reformat DESCRIPTION files. The package provides two APIs, one is object oriented, the other one is procedural and manipulates the files in place.

---

• Installation
• The object oriented API
  • Introduction
  • Loading or creating new DESCRIPTION files
  • Normalizing DESCRIPTION files
  • Querying, changing and removing fields
  • Dependencies
  • Collate fields
  • Authors
• The procedural API
• License

Installation

# Install the released version from CRAN
install.packages("desc")

# Or the development version from GitHub:
# install.packages("pak")
pak::pak("r-lib/desc")

The object oriented API

library(desc)

Introduction

The object oriented API uses R6 classes.

Loading or creating new DESCRIPTION files

A new description object can be created by reading a DESCRIPTION file form the disk. By default the DESCRIPTION file in the current directory is read:

desc <- description$new()

desc

#> Package: desc
#> Title: Manipulate DESCRIPTION Files
#> Version: 1.0.0
#> Author: Gábor Csárdi
#> Maintainer: Gábor Csárdi <csardi.gabor@gmail.com>
#> Description: Tools to read, write, create, and manipulate DESCRIPTION
#>     files.  It is intented for packages that create or manipulate other
#>     packages.
#> License: MIT + file LICENSE
#> URL: https://github.com/r-lib/desc
#> BugReports: https://github.com/r-lib/desc/issues
#> Imports:
#>     R6
#> Suggests:
#>     newpackage,
#>     testthat,
#>     whoami
#> Encoding: UTF-8
#> LazyData: true
#> RoxygenNote: 5.0.0

A new object can also be created from scratch:

desc2 <- description$new("!new")
desc2

#> Package: {{ Package }}
#> Title: {{ Title }}
#> Version: 1.0.0
#> Authors@R (parsed):
#>     * Jo Doe <jodoe@dom.ain> [aut, cre]
#> Maintainer: {{ Maintainer }}
#> Description: {{ Description }}
#> License: {{ License }}
#> URL: {{ URL }}
#> BugReports: {{ BugReports }}
#> Encoding: UTF-8

Normalizing DESCRIPTION files

Most DESCRIPTION fields may be formatted in multiple equivalent ways. desc does not reformat fields, unless they are updated or reformatting is explicitly requested via a call to the normalize() method or using the normalize argument of the write() method.

Querying, changing and removing fields

get() and set() queries or updates a field:

desc$set("Package", "foo")
desc$get("Package")

#> Package 
#>   "foo"

They work with multiple fields as well:

desc$set(Package = "bar", Title = "Bar Package")
desc$get(c("Package", "Title"))

#>       Package         Title 
#>         "bar" "Bar Package"

Dependencies

Package dependencies can be set and updated via an easier API:

desc$get_deps()

#>       type    package version
#> 1 Suggests   testthat       *
#> 2 Suggests     whoami       *
#> 3 Suggests newpackage       *
#> 4  Imports         R6       *

desc$set_dep("mvtnorm")
desc$set_dep("Rcpp", "LinkingTo")
desc$get_deps()

#>        type    package version
#> 1  Suggests   testthat       *
#> 2  Suggests     whoami       *
#> 3  Suggests newpackage       *
#> 4   Imports    mvtnorm       *
#> 5   Imports         R6       *
#> 6 LinkingTo       Rcpp       *

desc

#> Package: bar
#> Title: Bar Package
#> Version: 1.0.0
#> Author: Gábor Csárdi
#> Maintainer: Gábor Csárdi <csardi.gabor@gmail.com>
#> Description: Tools to read, write, create, and manipulate DESCRIPTION
#>     files.  It is intented for packages that create or manipulate other
#>     packages.
#> License: MIT + file LICENSE
#> URL: https://github.com/r-lib/desc
#> BugReports: https://github.com/r-lib/desc/issues
#> Imports:
#>     mvtnorm,
#>     R6
#> Suggests:
#>     newpackage,
#>     testthat,
#>     whoami
#> LinkingTo:
#>     Rcpp
#> Encoding: UTF-8
#> LazyData: true
#> RoxygenNote: 5.0.0

Collate fields

Collate fields can be queried and set using simple character vectors of file names:

desc$set_collate(list.files("../R"))

#> Warning in idesc_set_collate(self, private, files, match.arg(which)): No files
#> in 'Collate' field

desc$get_collate()

#> character(0)

Authors

Authors information, when specified via the Authors@R field, also has a simplified API:

desc <- description$new("tools/pkg2")
desc$get_authors()

#> [1] "Hadley Wickham <h.wickham@gmail.com> [aut, cre, cph]"
#> [2] "Peter Danenberg <pcd@roxygen.org> [aut, cph]"        
#> [3] "Manuel Eugster [aut, cph]"                           
#> [4] "RStudio [cph]"

desc$add_author("Bugs", "Bunny", email = "bb@acme.com")
desc$add_me()
desc$add_author_gh("jeroen")
desc$get_authors()

#> [1] "Hadley Wickham <h.wickham@gmail.com> [aut, cre, cph]"
#> [2] "Peter Danenberg <pcd@roxygen.org> [aut, cph]"        
#> [3] "Manuel Eugster [aut, cph]"                           
#> [4] "RStudio [cph]"                                       
#> [5] "Bugs Bunny <bb@acme.com>"                            
#> [6] "First Last <first.last@dom.com> [ctb]"               
#> [7] "Jeroen Ooms <jeroen@berkeley.edu> [ctb]"

If the Author field is specified, it can be changed to a Authors@R field using coerce_authors_at_r(), incorporating the Maintainer information if necessary:

desc <- description$new("!new")
desc$del("Authors@R")
desc$del("Maintainer")
desc$set(Author = "Gábor Csárdi <csardi.gabor@gmail.com>")
desc$get_authors()

#> Error in ensure_authors_at_r(self): No 'Authors@R' field!
#> You can create one with $add_author.
#> You can also use $coerce_authors_at_r() to change Author fields

desc$coerce_authors_at_r()
desc$get_authors()

#> [1] "Gábor Csárdi <csardi.gabor@gmail.com> [aut]"

The procedural API

The procedural API is simpler to use for one-off DESCRIPTION manipulation, since it does not require dealing with description objects. Each object oriented method has a procedural counterpart that works on a file, and potentially writes its result back to the same file.

For example, adding a new dependency to DESCRIPTION in the current working directory can be done with

desc_set_dep("newpackage", "Suggests")

#> Package: desc
#> Title: Manipulate DESCRIPTION Files
#> Version: 1.4.3.9000
#> Authors@R (parsed):
#>     * Gábor Csárdi <csardi.gabor@gmail.com> [aut, cre]
#>     * Kirill Müller [aut]
#>     * Jim Hester <james.f.hester@gmail.com> [aut]
#>     * Maëlle Salmon [ctb] (ORCID: <https://orcid.org/0000-0002-2815-0399>)
#>     * Posit Software, PBC [cph, fnd] (ROR: <https://ror.org/03wc8by49>)
#> Maintainer: Gábor Csárdi <csardi.gabor@gmail.com>
#> Description: Tools to read, write, create, and manipulate DESCRIPTION
#>     files.  It is intended for packages that create or manipulate other
#>     packages.
#> License: MIT + file LICENSE
#> URL: https://desc.r-lib.org/, https://github.com/r-lib/desc
#> BugReports: https://github.com/r-lib/desc/issues
#> Depends:
#>     R (>= 3.4)
#> Imports:
#>     cli,
#>     R6,
#>     utils
#> Suggests:
#>     callr,
#>     covr,
#>     gh,
#>     newpackage,
#>     spelling,
#>     testthat,
#>     whoami,
#>     withr
#> Config/Needs/website: tidyverse/tidytemplate
#> Config/testthat/edition: 3
#> Config/usethis/last-upkeep: 2025-04-23
#> Encoding: UTF-8
#> Language: en-US
#> Roxygen: list(r6 = FALSE, load = "installed", markdown = TRUE)
#> RoxygenNote: 7.3.2.9000
#> Collate:
#>     'assertions.R'
#>     'authors-at-r.R'
#>     'built.R'
#>     'classes.R'
#>     'collate.R'
#>     'constants.R'
#>     'deps.R'
#>     'desc-package.R'
#>     'description.R'
#>     'encoding.R'
#>     'find-package-root.R'
#>     'latex.R'
#>     'non-oo-api.R'
#>     'package-archives.R'
#>     'read.R'
#>     'remotes.R'
#>     'str.R'
#>     'syntax_checks.R'
#>     'urls.R'
#>     'utils.R'
#>     'validate.R'
#>     'version.R'

This added newpackage to the Suggests field:

desc_get("Suggests")

#>                                                                                                  Suggests 
#> "\n    callr,\n    covr,\n    gh,\n    newpackage,\n    spelling,\n    testthat,\n    whoami,\n    withr"

So the full list of dependencies are now

desc_get_deps()

#>        type    package version
#> 1   Depends          R  >= 3.4
#> 2   Imports        cli       *
#> 3   Imports         R6       *
#> 4   Imports      utils       *
#> 5  Suggests      callr       *
#> 6  Suggests       covr       *
#> 7  Suggests         gh       *
#> 8  Suggests newpackage       *
#> 9  Suggests   spelling       *
#> 10 Suggests   testthat       *
#> 11 Suggests     whoami       *
#> 12 Suggests      withr       *

Code of Conduct

Please note that the desc project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.