feat: git_restore()

NAMESPACE

@@ -66,6 +66,7 @@ export(git_remote_set_url)
 export(git_reset_hard)
 export(git_reset_mixed)
 export(git_reset_soft)
+export(git_restore)
 export(git_revert)
 export(git_rm)
 export(git_signature)
@@ -158,6 +159,7 @@ useDynLib(gert,R_git_repository_open)
 useDynLib(gert,R_git_repository_path)
 useDynLib(gert,R_git_repository_rm)
 useDynLib(gert,R_git_reset)
+useDynLib(gert,R_git_restore)
 useDynLib(gert,R_git_revert)
 useDynLib(gert,R_git_signature_create)
 useDynLib(gert,R_git_signature_default)

NEWS.md

@@ -1,5 +1,6 @@
 # gert (development version)
 
+- Add `git_restore()` function (#259)
 - Add `git_config_get()`, `git_config_local_get()`, and `git_config_global_get()` to retrieve a single named config option, returning `NULL` if unset (#267).
 - `git_clone()` without a `path` argument now clones into a directory named after the
 "humanish" part of the URL, so "git@github.com:francisbarton/myrepo.git" gets cloned into `myrepo` (@francisbardon, #192).

R/commit.R

@@ -322,22 +322,7 @@ git_revert <- function(
   assert_string(ref)
   stopifnot(is.logical(commit), length(commit) == 1)
 
-  sha <- tryCatch(git_commit_id(ref, repo = repo), error = function(e) {
-    stop(sprintf(
-      "Can't find reference/commit '%s' in the current branch history",
-      ref
-    ))
-  })
-
-  head_sha <- git_commit_id("HEAD", repo = repo)
-  sha_descends_from_head <- git_commit_descendant_of(
-    ancestor = sha,
-    ref = "HEAD",
-    repo = repo
-  )
-  if (sha != head_sha && !sha_descends_from_head) {
-    stop(sprintf("commit '%s' is not in the current branch history", ref))
-  }
+  sha <- check_ref_in_history(ref, repo)
 
   .Call(R_git_revert, repo, sha)
 

R/restore.R

@@ -0,0 +1,58 @@
+#' Restore working tree files
+#'
+#' Restores specified paths in the working tree from a given ref, equivalent
+#' to `git restore --source=<ref> <path>` (or the older
+#' `git checkout <ref> -- <path>`). The ref must be reachable from the
+#' current HEAD. By default restores from HEAD, discarding any local
+#' modifications.
+#'
+#' @export
+#' @name git_restore
+#' @rdname git_restore
+#' @family git
+#' @inheritParams git_open
+#' @param path character vector with file paths to restore, relative to the
+#'   repository root. Use `"."` to restore all tracked files.
+#' @param ref revision string with a branch/tag/commit to restore from.
+#'   Defaults to `"HEAD"`.
+#' @return Invisibly, the [git_status()] after restoring.
+#' @examplesIf interactive()
+#' repo <- file.path(tempdir(), "myrepo")
+#' git_init(repo)
+#'
+#' # Set a user if no default
+#' if (!user_is_configured()) {
+#'   git_config_set("user.name", "Jerry")
+#'   git_config_set("user.email", "jerry@gmail.com")
+#' }
+#'
+#' writeLines("hello", file.path(repo, "hello.txt"))
+#' git_add("hello.txt", repo = repo)
+#' git_commit("First commit", repo = repo)
+#'
+#' # Modify the file, then restore it from HEAD
+#' writeLines("oops", file.path(repo, "hello.txt"))
+#' git_restore("hello.txt", repo = repo)
+#' readLines(file.path(repo, "hello.txt"))  # "hello"
+#'
+#' unlink(repo, recursive = TRUE)
+#' @useDynLib gert R_git_restore
+git_restore <- function(path, ref = "HEAD", repo = ".") {
+  repo <- git_open(repo)
+  path <- check_path_tracked(as.character(path), repo)
+  ref <- check_ref_in_history(ref, repo)
+  .Call(R_git_restore, repo, path, ref)
+  invisible(git_status(repo = repo))
+}
+
+check_path_tracked <- function(path, repo) {
+  if (identical(path, ".")) {
+    return(character(0))
+  }
+  tracked <- git_ls(repo = repo)$path
+  untracked <- setdiff(path, tracked)
+  if (length(untracked) > 0) {
+    stop("Path(s) not tracked by git: ", toString(untracked))
+  }
+  path
+}

R/utils-sha.R

@@ -0,0 +1,17 @@
+check_ref_in_history <- function(ref, repo) {
+  sha <- tryCatch(git_commit_id(ref, repo = repo), error = function(e) {
+    stop(sprintf("Cannot resolve '%s' to a commit", ref))
+  })
+
+  head_sha <- git_commit_id("HEAD", repo = repo)
+  sha_descends_from_head <- git_commit_descendant_of(
+    ancestor = sha,
+    ref = "HEAD",
+    repo = repo
+  )
+  if (sha != head_sha && !sha_descends_from_head) {
+    stop(sprintf("'%s' is not in the current branch history", ref))
+  }
+
+  sha
+}

src/files.c

@@ -211,3 +211,17 @@ SEXP R_git_status_list(SEXP ptr, SEXP show_staged, SEXP path_spec){
   UNPROTECT(3);
   return out;
 }
+
+SEXP R_git_restore(SEXP ptr, SEXP files, SEXP ref){
+  git_repository *repo = get_git_repository(ptr);
+  git_object *obj = resolve_refish(ref, repo);
+  git_checkout_options opts = GIT_CHECKOUT_OPTIONS_INIT;
+  opts.checkout_strategy = GIT_CHECKOUT_FORCE;
+  git_strarray *paths = files_to_array(files);
+  opts.paths = *paths;
+  int err = git_checkout_tree(repo, obj, &opts);
+  git_strarray_free(paths);
+  git_object_free(obj);
+  bail_if(err, "git_checkout_tree");
+  return R_NilValue;
+}

src/init.c

@@ -52,6 +52,7 @@ extern SEXP R_git_remote_push(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
 extern SEXP R_git_remote_refspecs(SEXP, SEXP);
 extern SEXP R_git_remote_remove(SEXP, SEXP);
 extern SEXP R_git_remote_set_url(SEXP, SEXP, SEXP);
+extern SEXP R_git_restore(SEXP, SEXP, SEXP);
 extern SEXP R_git_revert(SEXP, SEXP);
 extern SEXP R_git_repository_add(SEXP, SEXP, SEXP);
 extern SEXP R_git_repository_clone(SEXP, SEXP, SEXP, SEXP, SEXP, SEXP, SEXP, SEXP);
@@ -146,6 +147,7 @@ static const R_CallMethodDef CallEntries[] = {
   {"R_git_repository_path",     (DL_FUNC) &R_git_repository_path,     1},
   {"R_git_repository_rm",       (DL_FUNC) &R_git_repository_rm,       2},
   {"R_git_reset",               (DL_FUNC) &R_git_reset,               3},
+  {"R_git_restore",             (DL_FUNC) &R_git_restore,             3},
   {"R_git_revert",              (DL_FUNC) &R_git_revert,              2},
   {"R_git_signature_create",    (DL_FUNC) &R_git_signature_create,    4},
   {"R_git_signature_default",   (DL_FUNC) &R_git_signature_default,   1},