[RFC PATCH v2 32/36] clone: use server-recommended bundle URI

["Ævar Arnfjörð Bjarmason" <avarab@gmail.com>]

From: Derrick Stolee <derrickstolee@github.com>

After the ref advertisement initializes the connection between the
client and the remote, use the 'features' capability (if available) to
get a list of recommended features from the server.

In this change, we only update the bundle URI setting. The bundles are
downloaded immediately afterwards if the bundle URI becomes non-null.

RFC-TODO: don't overwrite a given --bundle-uri option.
RFC-TODO: implement the other capabilities.
RFC-TODO: guard this entire request behind opt-in config.
RFC-TODO: prevent using an HTTP(S) URI when in an SSH clone.
RFC-TODO: prevent using a local path for the bundle URI.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
---
 builtin/clone.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/builtin/clone.c b/builtin/clone.c
index af64bd273b7..81c14a9f5d7 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -890,6 +890,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 	int err = 0, complete_refs_before_fetch = 1;
 	int submodule_progress;
 	int filter_submodules = 0;
+	struct string_list *feature_list = NULL;
 
 	struct transport_ls_refs_options transport_ls_refs_options =
 		TRANSPORT_LS_REFS_OPTIONS_INIT;
@@ -1241,11 +1242,23 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 
 	refs = transport_get_remote_refs(transport, &transport_ls_refs_options);
 
-	/*
-	 * NOTE: The bundle URI download takes place after transport_get_remote_refs()
-	 * because a later change will introduce a check for recommended features,
-	 * which might include a recommended bundle URI.
-	 */
+	feature_list = transport_remote_features(transport);
+
+	if (feature_list) {
+		struct string_list_item *item;
+		for_each_string_list_item(item, feature_list) {
+			char *value;
+			char *equals = strchr(item->string, '=');
+
+			if (!equals)
+				continue;
+			*equals = '\0';
+			value = equals + 1;
+
+			if (!strcmp(item->string, "bundleuri"))
+				bundle_uri = value;
+		}
+	}
 
 	/*
 	 * Before fetching from the remote, download and install bundle
@@ -1265,7 +1278,7 @@ int cmd_clone(int argc, const char **argv, const char *prefix)
 		if (filter)
 			git_config_set("fetch.bundlefilter", filter);
 
-		if (!fetch_bundle_uri(bundle_uri, filter))
+		if (fetch_bundle_uri(bundle_uri, filter))
 			warning(_("failed to fetch objects from bundle URI '%s'"),
 				bundle_uri);
 	}
-- 
2.36.0.rc2.902.g60576bbc845