tar_git_checkout {gittargets}

Check out a snapshot of the data (Git)

Description

Check out a snapshot of the data associated with a particular code commit (default: HEAD).

Usage

tar_git_checkout(
  ref = "HEAD",
  code = getwd(),
  store = targets::tar_config_get("store"),
  force = FALSE,
  verbose = TRUE
)

Arguments

ref

Character of length 1. SHA1 hash, branch name, or other reference in the code repository that points to a code commit. (You can also identify the code commit by supplying a data branch of the form ⁠code=<SHA1>⁠.) Defaults to "HEAD", which points to the currently checked out code commit.

Once the desired code commit is identified, tar_git_snapshot() checks out the latest corresponding data snapshot. There may be earlier data snapshots corresponding to this code commit, but tar_git_snapshot() only checks out the latest one. To check out an earlier superseded data snapshot, you will need to manually use command line Git in the data repository.

If tar_git_snapshot() cannot find a data snapshot for the desired code commit, then it will throw an error. For a list of commits in the current code branch that have available data snapshots, see the commit_code column of the output of tar_git_log().

code

Character of length 1, directory path to the code repository, usually the root of the targets project.

store

Character of length 1, path to the data store of the pipeline. If NULL, the store setting is left unchanged in the YAML configuration file (default: ⁠_targets.yaml⁠). Usually, the data store lives at ⁠_targets⁠. Set store to a custom directory to specify a path other than ⁠_targets/⁠. The path need not exist before the pipeline begins, and it need not end with "_targets", but it must be writeable. For optimal performance, choose a storage location with fast read/write access. If the argument NULL, the setting is not modified. Use tar_config_unset() to delete a setting.

force

ignore conflicts and overwrite modified files

verbose

Logical of length 1, whether to print R console messages confirming that a snapshot was created.

Value

Nothing (invisibly).

See Also

Other git: tar_git_init(), tar_git_log(), tar_git_ok(), tar_git_snapshot(), tar_git_status_code(), tar_git_status_data(), tar_git_status_targets(), tar_git_status()

Examples

if (Sys.getenv("TAR_EXAMPLES") == "true" && tar_git_ok(verbose = FALSE)) {
targets::tar_dir({ # Containing code does not modify the user's filespace.
# Work on an initial branch.
targets::tar_script(tar_target(data, "old_data"))
targets::tar_make()
targets::tar_read(data) # "old_data"
gert::git_init()
gert::git_add("_targets.R")
gert::git_commit("First commit")
gert::git_branch_create("old_branch")
tar_git_init()
# Work on a new branch.
tar_git_snapshot(status = FALSE, verbose = FALSE)
targets::tar_script(tar_target(data, "new_data"))
targets::tar_make()
targets::tar_read(data) # "new_data"
gert::git_branch_create("new_branch")
gert::git_add("_targets.R")
gert::git_commit("Second commit")
tar_git_snapshot(status = FALSE, verbose = FALSE)
# Go back to the old branch.
gert::git_branch_checkout("old_branch")
# The target is out of date because we only reverted the code.
targets::tar_outdated()
# But tar_git_checkout() lets us restore the old version of the data!
tar_git_checkout()
targets::tar_read(data) # "old_data"
# Now, the target is up to date! And we did not even have to rerun it!
targets::tar_outdated()
})
}