Feature Request: renv::snapshot(minimal = TRUE) to generate a slimmed-down renv.lock

[fzenoni]

Currently, renv.lock files can become bloated because they store all dependencies, metadata, and sources. A minimal lockfile containing only package names and versions would be useful, especially for Docker-based deployments or lightweight version control.

Could an option to renv::snapshot(), such as:

renv::snapshot(minimal = TRUE)

be added, which would generate a lighter renv.lock file with only explicitly used packages and their versions, without extra metadata?

The output could be for example:

{
  "R": {
    "Version": "4.2.1"
  },
  "Packages": {
    "shiny": {
      "Version": "1.7.3"
    },
    "ggplot2": {
      "Version": "3.4.1"
    },
    "dplyr": {
      "Version": "1.1.2"
    }
  }
}

Obtaining such an output currently requires a custom script like:

generate_minimal_lockfile <- function(input_lockfile = "renv.lock", output_file = "renv_minimal.lock") {
  library(jsonlite)
  lock_data <- fromJSON(input_lockfile, simplifyVector = FALSE)
  minimal_lock <- list(R = list(Version = lock_data$R$Version), Packages = lapply(lock_data$Packages, function(pkg) list(Version = pkg$Version)))
  writeLines(toJSON(minimal_lock, pretty = TRUE, auto_unbox = TRUE), output_file)
}
generate_minimal_lockfile()

Thanks for considering it.

[kevinushey]

Is there a specific motivation for wanting a more minimal lockfile? See also from NEWS:

* `renv` now includes additional package DESCRIPTION fields in the lockfile.
  This can be useful for validating the provenance of packages recorded in the
  lockfile, and also for applications using `renv` which would like to
  recompute the hash used for package caching from the lockfile itself.

  If needed, old-style lockfiles can be generated by setting the option
  `options(renv.lockfile.version = 1)`. Note that this version of `renv`
  remains compatible both with the older (minimal) lockfiles, as well
  as with the newer lockfiles in this release. (#2057)

[fzenoni]

Hi @kevinushey, thank you for your answer.

There is no specific motivation, other than the will to generate a file closer to something like requirements.txt from Python. Your suggestion answers my question.