Merge branch 'ab/checkout-default-remote'

"git checkout" and "git worktree add" learned to honor
checkout.defaultRemote when auto-vivifying a local branch out of a
remote tracking branch in a repository with multiple remotes that
have tracking branches that share the same names.

* ab/checkout-default-remote:
  checkout & worktree: introduce checkout.defaultRemote
  checkout: add advice for ambiguous "checkout <branch>"
  builtin/checkout.c: use "ret" variable for return
  checkout: pass the "num_matches" up to callers
  checkout.c: change "unique" member to "num_matches"
  checkout.c: introduce an *_INIT macro
  checkout.h: wrap the arguments to unique_tracking_name()
  checkout tests: index should be clean after dwim checkout

1 files changed, 32 insertions, 5 deletions

diff --git a/checkout.c b/checkout.c
index bdefc888ba..c72e9f9773 100644
--- a/checkout.c
+++ b/checkout.c
@@ -2,14 +2,20 @@
 #include "remote.h"
 #include "refspec.h"
 #include "checkout.h"
+#include "config.h"
 
 struct tracking_name_data {
 	/* const */ char *src_ref;
 	char *dst_ref;
 	struct object_id *dst_oid;
-	int unique;
+	int num_matches;
+	const char *default_remote;
+	char *default_dst_ref;
+	struct object_id *default_dst_oid;
 };
 
+#define TRACKING_NAME_DATA_INIT { NULL, NULL, NULL, 0, NULL, NULL, NULL }
+
 static int check_tracking_name(struct remote *remote, void *cb_data)
 {
 	struct tracking_name_data *cb = cb_data;
@@ -21,24 +27,45 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		free(query.dst);
 		return 0;
 	}
+	cb->num_matches++;
+	if (cb->default_remote && !strcmp(remote->name, cb->default_remote)) {
+		struct object_id *dst = xmalloc(sizeof(*cb->default_dst_oid));
+		cb->default_dst_ref = xstrdup(query.dst);
+		oidcpy(dst, cb->dst_oid);
+		cb->default_dst_oid = dst;
+	}
 	if (cb->dst_ref) {
 		free(query.dst);
-		cb->unique = 0;
 		return 0;
 	}
 	cb->dst_ref = query.dst;
 	return 0;
 }
 
-const char *unique_tracking_name(const char *name, struct object_id *oid)
+const char *unique_tracking_name(const char *name, struct object_id *oid,
+				 int *dwim_remotes_matched)
 {
-	struct tracking_name_data cb_data = { NULL, NULL, NULL, 1 };
+	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
+	const char *default_remote = NULL;
+	if (!git_config_get_string_const("checkout.defaultremote", &default_remote))
+		cb_data.default_remote = default_remote;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
 	for_each_remote(check_tracking_name, &cb_data);
+	if (dwim_remotes_matched)
+		*dwim_remotes_matched = cb_data.num_matches;
 	free(cb_data.src_ref);
-	if (cb_data.unique)
+	free((char *)default_remote);
+	if (cb_data.num_matches == 1) {
+		free(cb_data.default_dst_ref);
+		free(cb_data.default_dst_oid);
 		return cb_data.dst_ref;
+	}
 	free(cb_data.dst_ref);
+	if (cb_data.default_dst_ref) {
+		oidcpy(oid, cb_data.default_dst_oid);
+		free(cb_data.default_dst_oid);
+		return cb_data.default_dst_ref;
+	}
 	return NULL;
 }