builtin/clone.c: add --reject-shallow option

In some scenarios, users may want more history than the repository
offered for cloning, which happens to be a shallow repository, can
give them. But because users don't know it is a shallow repository
until they download it to local, we may want to refuse to clone
this kind of repository, without creating any unnecessary files.

The '--depth=x' option cannot be used as a solution; the source may
be deep enough to give us 'x' commits when cloned, but the user may
later need to deepen the history to arbitrary depth.

Teach '--reject-shallow' option to "git clone" to abort as soon as
we find out that we are cloning from a shallow repository.

Signed-off-by: Li Linchao <lilinchao@oschina.cn>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 21 insertions, 0 deletions

diff --git a/builtin/clone.c b/builtin/clone.c
index 51e844a2de..2a5485b724 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -50,6 +50,8 @@ static int option_no_checkout, option_bare, option_mirror, option_single_branch
 static int option_local = -1, option_no_hardlinks, option_shared;
 static int option_no_tags;
 static int option_shallow_submodules;
+static int option_reject_shallow = -1;    /* unspecified */
+static int config_reject_shallow = -1;    /* unspecified */
 static int deepen;
 static char *option_template, *option_depth, *option_since;
 static char *option_origin = NULL;
@@ -90,6 +92,8 @@ static struct option builtin_clone_options[] = {
 	OPT__VERBOSITY(&option_verbosity),
 	OPT_BOOL(0, "progress", &option_progress,
 		 N_("force progress reporting")),
+	OPT_BOOL(0, "reject-shallow", &option_reject_shallow,
+		 N_("don't clone shallow repository")),
 	OPT_BOOL('n', "no-checkout", &option_no_checkout,
 		 N_("don't create a checkout")),
 	OPT_BOOL(0, "bare", &option_bare, N_("create a bare repository")),
@@ -858,6 +862,9 @@ static int git_clone_config(const char *k, const char *v, void *cb)
 		free(remote_name);
 		remote_name = xstrdup(v);
 	}
+	if (!strcmp(k, "clone.rejectshallow"))
+		config_reject_shallow = git_config_bool(k, v);
+
 	return git_default_config(k, v, cb);
 }
 
@@ -963,6 +970,7 @@ static int path_exists(const char *path)
 int cmd_clone(int argc, const char **argv, const char *prefix)
 {
 	int is_bundle = 0, is_local;
+	int reject_shallow = 0;
 	const char *repo_name, *repo, *work_tree, *git_dir;
 	char *path, *dir, *display_repo = NULL;
 	int dest_exists, real_dest_exists = 0;
@@ -1157,6 +1165,15 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	git_config(git_clone_config, NULL);
 
 	/*
+	 * If option_reject_shallow is specified from CLI option,
+	 * ignore config_reject_shallow from git_clone_config.
+	 */
+	if (config_reject_shallow != -1)
+		reject_shallow = config_reject_shallow;
+	if (option_reject_shallow != -1)
+		reject_shallow = option_reject_shallow;
+
+	/*
 	 * apply the remote name provided by --origin only after this second
 	 * call to git_config, to ensure it overrides all config-based values.
 	 */
@@ -1216,6 +1233,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		if (filter_options.choice)
 			warning(_("--filter is ignored in local clones; use file:// instead."));
 		if (!access(mkpath("%s/shallow", path), F_OK)) {
+			if (reject_shallow)
+				die(_("source repository is shallow, reject to clone."));
 			if (option_local > 0)
 				warning(_("source repository is shallow, ignoring --local"));
 			is_local = 0;
@@ -1227,6 +1246,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 
 	transport_set_option(transport, TRANS_OPT_KEEP, "yes");
 
+	if (reject_shallow)
+		transport_set_option(transport, TRANS_OPT_REJECT_SHALLOW, "1");
 	if (option_depth)
 		transport_set_option(transport, TRANS_OPT_DEPTH,
 				     option_depth);