Use packages as they were on a date — pixi_set

Make Pixi leave out every package published after a date, with the project's exclude-newer setting. The project then gets packages as they were on that day, like a snapshot of a package repository: useful to rerun an old analysis with the versions it was written for, or to check that a package still works with what users had a year ago. pixi_set_date() sets it, and updates pixi.lock to match.

A duration, such as "7d", leaves out packages published in the last week instead, e.g. to stay clear of a release that turns out to be broken or compromised. pixi_set_date(NULL) removes the setting; packages stay as they are until you update them with pixi_update().

Only packages that were on conda-forge (or the project's other channels) at the time are available, even if they were on CRAN then.

Usage

pixi_set_date(date, path = NULL)

Arguments

date: A date, such as "2025-06-01" or Sys.Date() - 365, a timestamp ("2025-06-01T12:00:00Z"), or a duration, such as "7d". NULL removes the setting.
path: The project. Defaults to the project of the running Pixi environment, or the working directory.

Value

The previous setting, or NULL, invisibly.

Details

pixi_add() pins the versions it adds, so an existing project's pins may be newer than an earlier date. Pixi then can't solve the project, and pixi.toml is left as it was. Setting the date when you create the project, with use_pixi(date = ), avoids that.

The date applies to Pixi's build backend too, so packages built from source (pixi_add("github::...")) need a date of 2026-10-15 or later, when pixi-build-r 0.2.0 was out, or a duration.

See https://pixi.prefix.dev/latest/reference/pixi_manifest/#exclude-newer-optional.

Examples

if (FALSE) { # \dontrun{
pixi_set_date("2025-06-01")
pixi_set_date("7d")
pixi_set_date(NULL)
} # }