sparse-checkout: match some 'clean' behavior

The 'git sparse-checkout clean' subcommand is somewhat similar to 'git
clean' in that it will delete files that should not be in the worktree.
The big difference is that it focuses on the directories that should not
be in the worktree due to cone-mode sparse-checkout. It also does not
discriminate in the kinds of files and focuses on deleting entire
directories.

However, there are some restrictions that would be good to bring over
from 'git clean', specifically how it refuses to do anything without the
'-f'/'--force' or '-n'/'--dry-run' arguments. The 'clean.requireForce'
config can be set to 'false' to imply '--force'.

Add this behavior to avoid accidental deletion of files that cannot be
recovered from Git.

Signed-off-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 14 insertions, 1 deletions

diff --git a/builtin/sparse-checkout.c b/builtin/sparse-checkout.c
index f7caa28f3f..d777b64960 100644
--- a/builtin/sparse-checkout.c
+++ b/builtin/sparse-checkout.c
@@ -931,6 +931,7 @@ static char const * const builtin_sparse_checkout_clean_usage[] = {
 };
 
 static const char *msg_remove = N_("Removing %s\n");
+static const char *msg_would_remove = N_("Would remove %s\n");
 
 static int sparse_checkout_clean(int argc, const char **argv,
 				   const char *prefix,
@@ -939,8 +940,12 @@ static int sparse_checkout_clean(int argc, const char **argv,
 	struct strbuf full_path = STRBUF_INIT;
 	const char *msg = msg_remove;
 	size_t worktree_len;
+	int force = 0, dry_run = 0;
+	int require_force = 1;
 
 	struct option builtin_sparse_checkout_clean_options[] = {
+		OPT__DRY_RUN(&dry_run, N_("dry run")),
+		OPT__FORCE(&force, N_("force"), PARSE_OPT_NOCOMPLETE),
 		OPT_END(),
 	};
 
@@ -954,6 +959,13 @@ static int sparse_checkout_clean(int argc, const char **argv,
 			     builtin_sparse_checkout_clean_options,
 			     builtin_sparse_checkout_clean_usage, 0);
 
+	repo_config_get_bool(repo, "clean.requireforce", &require_force);
+	if (require_force && !force && !dry_run)
+		die(_("for safety, refusing to clean without one of --force or --dry-run"));
+
+	if (dry_run)
+		msg = msg_would_remove;
+
 	if (repo_read_index(repo) < 0)
 		die(_("failed to read index"));
 
@@ -977,7 +989,8 @@ static int sparse_checkout_clean(int argc, const char **argv,
 
 		printf(msg, ce->name);
 
-		if (remove_dir_recursively(&full_path, 0))
+		if (dry_run <= 0 &&
+		    remove_dir_recursively(&full_path, 0))
 			warning_errno(_("failed to remove '%s'"), ce->name);
 	}