path: root/builtin/checkout.c
diff options
authorJohan Herland <>2013-04-21 21:52:01 (GMT)
committerJunio C Hamano <>2013-04-21 22:14:41 (GMT)
commitfa83a33b22283e465aafdacc53ad0fddea55bdf4 (patch)
treeddc6297ab6a35dd61625a4dd7b77a0c7eab5f641 /builtin/checkout.c
parentec2764ee8fb9a37cc92e0a1bce3b49ae2de0ffbc (diff)
checkout: Use remote refspecs when DWIMming tracking branches
The DWIM mode of checkout allows you to run "git checkout foo" when there is no existing local ref or path called "foo", and there is exactly _one_ remote with a remote-tracking branch called "foo". Git will automatically create a new local branch called "foo" using the remote-tracking "foo" as its starting point and configured upstream. For example, consider the following unconventional (but perfectly valid) remote setup: [remote "origin"] fetch = refs/heads/*:refs/remotes/origin/* [remote "frotz"] fetch = refs/heads/*:refs/remotes/frotz/nitfol/* Case 1: Assume both "origin" and "frotz" have remote-tracking branches called "foo", at "refs/remotes/origin/foo" and "refs/remotes/frotz/nitfol/foo" respectively. In this case "git checkout foo" should fail, because there is more than one remote with a "foo" branch. Case 2: Assume only "frotz" have a remote-tracking branch called "foo". In this case "git checkout foo" should succeed, and create a local branch "foo" from "refs/remotes/frotz/nitfol/foo", using remote branch "foo" from "frotz" as its upstream. The current code hardcodes the assumption that all remote-tracking branches must match the "refs/remotes/$remote/*" pattern (which is true for remotes with "conventional" refspecs, but not true for the "frotz" remote above). When running "git checkout foo", the current code looks for exactly one ref matching "refs/remotes/*/foo", hence in the above example, it fails to find "refs/remotes/frotz/nitfol/foo", which causes it to fail both case #1 and #2. The better way to handle the above example is to actually study the fetch refspecs to deduce the candidate remote-tracking branches for "foo"; i.e. assume "foo" is a remote branch being fetched, and then map "refs/heads/foo" through the refspecs in order to get the corresponding remote-tracking branches "refs/remotes/origin/foo" and "refs/remotes/frotz/nitfol/foo". Finally we check which of these happens to exist in the local repo, and if there is exactly one, we have an unambiguous match for "git checkout foo", and may proceed. This fixes most of the failing tests introduced in the previous patch. Signed-off-by: Johan Herland <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'builtin/checkout.c')
1 files changed, 22 insertions, 20 deletions
diff --git a/builtin/checkout.c b/builtin/checkout.c
index eb51872..bcb18c8 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -822,38 +822,40 @@ static int git_checkout_config(const char *var, const char *value, void *cb)
struct tracking_name_data {
- const char *name;
- char *remote;
+ /* const */ char *src_ref;
+ char *dst_ref;
+ unsigned char *dst_sha1;
int unique;
-static int check_tracking_name(const char *refname, const unsigned char *sha1,
- int flags, void *cb_data)
+static int check_tracking_name(struct remote *remote, void *cb_data)
struct tracking_name_data *cb = cb_data;
- const char *slash;
- if (prefixcmp(refname, "refs/remotes/"))
- return 0;
- slash = strchr(refname + 13, '/');
- if (!slash || strcmp(slash + 1, cb->name))
+ struct refspec query;
+ memset(&query, 0, sizeof(struct refspec));
+ query.src = cb->src_ref;
+ if (remote_find_tracking(remote, &query) ||
+ get_sha1(query.dst, cb->dst_sha1))
return 0;
- if (cb->remote) {
+ if (cb->dst_ref) {
cb->unique = 0;
return 0;
- cb->remote = xstrdup(refname);
+ cb->dst_ref = xstrdup(query.dst);
return 0;
-static const char *unique_tracking_name(const char *name)
+static const char *unique_tracking_name(const char *name, unsigned char *sha1)
- struct tracking_name_data cb_data = { NULL, NULL, 1 };
- = name;
- for_each_ref(check_tracking_name, &cb_data);
+ struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
+ char src_ref[PATH_MAX];
+ snprintf(src_ref, PATH_MAX, "refs/heads/%s", name);
+ cb_data.src_ref = src_ref;
+ cb_data.dst_sha1 = sha1;
+ for_each_remote(check_tracking_name, &cb_data);
if (cb_data.unique)
- return cb_data.remote;
- free(cb_data.remote);
+ return cb_data.dst_ref;
+ free(cb_data.dst_ref);
return NULL;
@@ -916,8 +918,8 @@ static int parse_branchname_arg(int argc, const char **argv,
if (dwim_new_local_branch_ok &&
!check_filename(NULL, arg) &&
argc == 1) {
- const char *remote = unique_tracking_name(arg);
- if (!remote || get_sha1(remote, rev))
+ const char *remote = unique_tracking_name(arg, rev);
+ if (!remote)
return argcount;
*new_branch = arg;
arg = remote;