clone: define shallow clone boundary with --shallow-exclude

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/git-clone.txt

@@ -196,6 +196,11 @@ objects from the source repository into a pack in the cloned repository.
 --shallow-since=<date>::
 	Create a shallow clone with a history after the specified time.
 
+--shallow-exclude=<revision>::
+	Create a shallow clone with a history, excluding commits
+	reachable from a specified remote branch or tag.  This option
+	can be specified multiple times.
+
 --[no-]single-branch::
 	Clone only the history leading to the tip of a single branch,
 	either specified by the `--branch` option or the primary

builtin/clone.c

@@ -44,6 +44,7 @@ static int deepen;
 static char *option_template, *option_depth, *option_since;
 static char *option_origin = NULL;
 static char *option_branch = NULL;
+static struct string_list option_not = STRING_LIST_INIT_NODUP;
 static const char *real_git_dir;
 static char *option_upload_pack = "git-upload-pack";
 static int option_verbosity;
@@ -89,6 +90,8 @@ static struct option builtin_clone_options[] = {
 		    N_("create a shallow clone of that depth")),
 	OPT_STRING(0, "shallow-since", &option_since, N_("time"),
 		    N_("create a shallow clone since a specific time")),
+	OPT_STRING_LIST(0, "shallow-exclude", &option_not, N_("revision"),
+			N_("deepen history of shallow clone by excluding rev")),
 	OPT_BOOL(0, "single-branch", &option_single_branch,
 		    N_("clone only one branch, HEAD or --branch")),
 	OPT_STRING(0, "separate-git-dir", &real_git_dir, N_("gitdir"),
@@ -852,7 +855,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		usage_msg_opt(_("You must specify a repository to clone."),
 			builtin_clone_usage, builtin_clone_options);
 
-	if (option_depth || option_since)
+	if (option_depth || option_since || option_not.nr)
 		deepen = 1;
 	if (option_single_branch == -1)
 		option_single_branch = deepen ? 1 : 0;
@@ -983,6 +986,8 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 			warning(_("--depth is ignored in local clones; use file:// instead."));
 		if (option_since)
 			warning(_("--shallow-since is ignored in local clones; use file:// instead."));
+		if (option_not.nr)
+			warning(_("--shallow-exclude is ignored in local clones; use file:// instead."));
 		if (!access(mkpath("%s/shallow", path), F_OK)) {
 			if (option_local > 0)
 				warning(_("source repository is shallow, ignoring --local"));
@@ -1004,6 +1009,9 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	if (option_since)
 		transport_set_option(transport, TRANS_OPT_DEEPEN_SINCE,
 				     option_since);
+	if (option_not.nr)
+		transport_set_option(transport, TRANS_OPT_DEEPEN_NOT,
+				     (const char *)&option_not);
 	if (option_single_branch)
 		transport_set_option(transport, TRANS_OPT_FOLLOWTAGS, "1");