Re: [PATCH v3] worktree add: improve message for ambiguous remote branch name

@@ -1343,13 +1343,50 @@ enum checkout_command {
 	CHECKOUT_RESTORE = 3,
 };
 
+static void be_explicit(enum checkout_command which_command,
+			const struct string_list *matched_remote_names)
+{
+	const char *cmdname;
+	struct string_list_item *item;
+
+	switch (which_command) {
+	case CHECKOUT_CHECKOUT:
+		cmdname = "checkout";
+		break;
+	case CHECKOUT_SWITCH:
+		cmdname = "switch";
+		break;
+	default:
+		BUG("command <%d> should not reach parse_remote_branch",
+		     which_command);
+		break;
+	}
+
+	advise(_("Branches with the same name appears in multiple remotes:"));
+	for_each_string_list_item(item, matched_remote_names) {
+		advise(_("  %s"), item->string);
+	}
+	advise(_("If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
+		 "you can do so by fully qualifying the name with the --track option:\n"
+		 "\n"
+		 "    git %s --track origin/<name>\n"
+		 "\n"
+		 "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
+		 "one remote, e.g. the 'origin' remote, consider setting\n"
+		 "checkout.defaultRemote=origin in your config."),
+	       cmdname);
+}
+
 static char *parse_remote_branch(const char *arg,
 				 struct object_id *rev,
 				 int could_be_checkout_paths,
 				 enum checkout_command which_command)
 {
 	int num_matches = 0;
-	char *remote = unique_tracking_name(arg, rev, &num_matches);
+	struct string_list matched_remote_names = STRING_LIST_INIT_DUP;
+
+	char *remote = unique_tracking_name(arg, rev, &num_matches,
+					    &matched_remote_names);
 
 	if (remote && could_be_checkout_paths) {
 		die(_("'%s' could be both a local file and a tracking branch.\n"

@@ -1358,37 +1395,14 @@ static char *parse_remote_branch(const char *arg,
 	}
 
 	if (!remote && num_matches > 1) {
-	    if (advice_enabled(ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME)) {
-		    const char *cmdname;
-
-		    switch (which_command) {
-		    case CHECKOUT_CHECKOUT:
-			    cmdname = "checkout";
-			    break;
-		    case CHECKOUT_SWITCH:
-			    cmdname = "switch";
-			    break;
-		    default:
-			    BUG("command <%d> should not reach parse_remote_branch",
-				which_command);
-			    break;
-		    }
-
-		    advise(_("If you meant to check out a remote tracking branch on, e.g. 'origin',\n"
-			     "you can do so by fully qualifying the name with the --track option:\n"
-			     "\n"
-			     "    git %s --track origin/<name>\n"
-			     "\n"
-			     "If you'd like to always have checkouts of an ambiguous <name> prefer\n"
-			     "one remote, e.g. the 'origin' remote, consider setting\n"
-			     "checkout.defaultRemote=origin in your config."),
-			   cmdname);
-	    }
-
-	    die(_("'%s' matched multiple (%d) remote tracking branches"),
-		arg, num_matches);
+		if (advice_enabled(ADVICE_CHECKOUT_AMBIGUOUS_REMOTE_BRANCH_NAME))
+			be_explicit(which_command, &matched_remote_names);
+		die(_("'%s' matched multiple (%d) remote tracking branches"),
+		    arg, num_matches);
 	}
 
+	string_list_clear(&matched_remote_names, 0);
+
 	return remote;
 }
 

@@ -782,7 +782,7 @@ static char *dwim_branch(const char *path, char **new_branch)
 	*new_branch = branchname;
 	if (guess_remote) {
 		struct object_id oid;
-		char *remote = unique_tracking_name(*new_branch, &oid, NULL);
+		char *remote = unique_tracking_name(*new_branch, &oid, NULL, NULL);
 		return remote;
 	}
 	return NULL;

@@ -904,7 +904,7 @@ static int add(int ac, const char **av, const char *prefix,
 
 		commit = lookup_commit_reference_by_name(branch);
 		if (!commit) {
-			remote = unique_tracking_name(branch, &oid, NULL);
+			remote = unique_tracking_name(branch, &oid, NULL, NULL);
 			if (remote) {
 				new_branch = branch;
 				branch = new_branch_to_free = remote;

@@ -8,6 +8,7 @@
 #include "checkout.h"
 #include "config.h"
 #include "strbuf.h"
+#include "string-list.h"
 
 struct tracking_name_data {
 	/* const */ char *src_ref;

@@ -17,6 +18,7 @@ struct tracking_name_data {
 	const char *default_remote;
 	char *default_dst_ref;
 	struct object_id *default_dst_oid;
+	struct string_list **remote_names;
 };
 
 #define TRACKING_NAME_DATA_INIT { 0 }

@@ -39,6 +41,8 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 		oidcpy(dst, cb->dst_oid);
 		cb->default_dst_oid = dst;
 	}
+	if (cb->remote_names)
+		string_list_append(*cb->remote_names, remote->name);
 	if (cb->dst_ref) {
 		free(query.dst);
 		return 0;

@@ -48,14 +52,20 @@ static int check_tracking_name(struct remote *remote, void *cb_data)
 }
 
 char *unique_tracking_name(const char *name, struct object_id *oid,
-			   int *dwim_remotes_matched)
+			   int *dwim_remotes_matched,
+			   struct string_list *dwim_remote_names)
 {
 	struct tracking_name_data cb_data = TRACKING_NAME_DATA_INIT;
 	const char *default_remote = NULL;
-	if (!repo_config_get_string_tmp(the_repository, "checkout.defaultremote", &default_remote))
+
+	if (!repo_config_get_string_tmp(the_repository,
+					"checkout.defaultremote",
+					&default_remote))
 		cb_data.default_remote = default_remote;
 	cb_data.src_ref = xstrfmt("refs/heads/%s", name);
 	cb_data.dst_oid = oid;
+	if (dwim_remote_names)
+		cb_data.remote_names = &dwim_remote_names;
 	for_each_remote(check_tracking_name, &cb_data);
 	if (dwim_remotes_matched)
 		*dwim_remotes_matched = cb_data.num_matches;

@@ -3,6 +3,8 @@
 
 #include "hash.h"
 
+struct string_list;
+
 /*
  * Check if the branch name uniquely matches a branch name on a remote
  * tracking branch.  Return the name of the remote if such a branch

@@ -10,6 +12,7 @@
  */
 char *unique_tracking_name(const char *name,
 			   struct object_id *oid,
-			   int *dwim_remotes_matched);
+			   int *dwim_remotes_matched,
+			   struct string_list *dwim_remote_names);
 
 #endif /* CHECKOUT_H */