add worktree.guessRemote config option

Some users might want to have the --guess-remote option introduced in
the previous commit on by default, so they don't have to type it out
every time they create a new worktree.

Add a config option worktree.guessRemote that allows users to configure
the default behaviour for themselves.

Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -3425,3 +3425,13 @@ web.browser::
 	Specify a web browser that may be used by some commands.
 	Currently only linkgit:git-instaweb[1] and linkgit:git-help[1]
 	may use it.
+
+worktree.guessRemote::
+	With `add`, if no branch argument, and neither of `-b` nor
+	`-B` nor `--detach` are given, the command defaults to
+	creating a new branch from HEAD.  If `worktree.guessRemote` is
+	set to true, `worktree add` tries to find a remote-tracking
+	branch whose name uniquely matches the new branch name.  If
+	such a branch exists, it is checked out and set as "upstream"
+	for the new branch.  If no such match can be found, it falls
+	back to creating a new branch from the current HEAD.

Documentation/git-worktree.txt

@@ -121,6 +121,9 @@ OPTIONS
 	branch in exactly one remote matching the basename of `<path>,
 	base the new branch on the remote-tracking branch, and mark
 	the remote-tracking branch as "upstream" from the new branch.
++
+This can also be set up as the default behaviour by using the
+`worktree.guessRemote` config option.
 
 --[no-]track::
 	When creating a new branch, if `<commit-ish>` is a branch,

builtin/worktree.c

@@ -33,8 +33,19 @@ struct add_opts {
 
 static int show_only;
 static int verbose;
+static int guess_remote;
 static timestamp_t expire;
 
+static int git_worktree_config(const char *var, const char *value, void *cb)
+{
+	if (!strcmp(var, "worktree.guessremote")) {
+		guess_remote = git_config_bool(var, value);
+		return 0;
+	}
+
+	return git_default_config(var, value, cb);
+}
+
 static int prune_worktree(const char *id, struct strbuf *reason)
 {
 	struct stat st;
@@ -343,7 +354,6 @@ static int add(int ac, const char **av, const char *prefix)
 	char *path;
 	const char *branch;
 	const char *opt_track = NULL;
-	int guess_remote = 0;
 	struct option options[] = {
 		OPT__FORCE(&opts.force, N_("checkout <branch> even if already checked out in other worktree")),
 		OPT_STRING('b', NULL, &opts.new_branch, N_("branch"),
@@ -591,7 +601,7 @@ int cmd_worktree(int ac, const char **av, const char *prefix)
 		OPT_END()
 	};
 
-	git_config(git_default_config, NULL);
+	git_config(git_worktree_config, NULL);
 
 	if (ac < 2)
 		usage_with_options(worktree_usage, options);

t/t2025-worktree-add.sh

@@ -413,4 +413,35 @@ test_expect_success 'git worktree add --guess-remote sets up tracking' '
 	)
 '
 
+test_expect_success 'git worktree add with worktree.guessRemote sets up tracking' '
+	test_when_finished rm -rf repo_a repo_b foo &&
+	setup_remote_repo repo_a repo_b &&
+	(
+		cd repo_b &&
+		git config worktree.guessRemote true &&
+		git worktree add ../foo
+	) &&
+	(
+		cd foo &&
+		test_branch_upstream foo repo_a foo &&
+		test_cmp_rev refs/remotes/repo_a/foo refs/heads/foo
+	)
+'
+
+test_expect_success 'git worktree --no-guess-remote option overrides config' '
+	test_when_finished rm -rf repo_a repo_b foo &&
+	setup_remote_repo repo_a repo_b &&
+	(
+		cd repo_b &&
+		git config worktree.guessRemote true &&
+		git worktree add --no-guess-remote ../foo
+	) &&
+	(
+		cd foo &&
+		test_must_fail git config "branch.foo.remote" &&
+		test_must_fail git config "branch.foo.merge" &&
+		! test_cmp_rev refs/remotes/repo_a/foo refs/heads/foo
+	)
+'
+
 test_done