[RFC PATCH v2 26/36] fetch: fetch bundles before fetching original data

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

From: Derrick Stolee <derrickstolee@github.com>

If a user cloned using a bundle URI, then they might want to re-use it
to download new bundles during 'git fetch' before fetching the remaining
objects from the origin server. Use the 'fetch.bundleURI' config as the
indicator for whether this extra step should happen.

Do not fetch bundles if --dry-run is specified.

RFC-TODO: add tests.

RFC-TODO: update Documentation/git-fetch.txt

RFC-TODO: update Documentation/config/

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
---
 builtin/fetch.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index e3791f09ed5..ac684bdf252 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -29,6 +29,7 @@
 #include "commit-graph.h"
 #include "shallow.h"
 #include "worktree.h"
+#include "bundle.h"
 
 #define FORCED_UPDATES_DELAY_WARNING_IN_MS (10 * 1000)
 
@@ -2180,6 +2181,22 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 	/* FETCH_HEAD never gets updated in --dry-run mode */
 	if (dry_run)
 		write_fetch_head = 0;
+	else {
+		/*
+		 * --dry-run mode skips bundle downloads, which might
+		 * update some refs.
+		 */
+		char *bundle_uri = NULL;
+		git_config_get_string("fetch.bundleuri", &bundle_uri);
+
+		if (bundle_uri) {
+			char *filter = NULL;
+			git_config_get_string("fetch.bundlefilter", &filter);
+			fetch_bundle_uri(bundle_uri, filter);
+			free(bundle_uri);
+			free(filter);
+		}
+	}
 
 	if (all) {
 		if (argc == 1)
-- 
2.36.0.rc2.902.g60576bbc845