"git checkout <commit>" will checkout the commit in question and
detach HEAD from the current branch. It is naturally a right thing to
do once you get git references. But detached HEAD is a scary concept
to new users because we show a lot of warnings and stuff, and it could
be hard to get out of (until you know better).
To keep switch a bit more friendly to new users, we only allow
entering detached HEAD mode when --detach is given. "git
switch" must take a branch (unless you create a new branch,
then of course switch can take any commit-ish)
---
builtin/checkout.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 73b7373414..d72e28aabb 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -45,6 +45,7 @@ struct checkout_opts {
int merge;
int force;
int force_detach;
+ int implicit_detach;
int writeout_stage;
int overwrite_ignore;
int ignore_skipworktree;
@@ -1298,6 +1299,29 @@ static int switch_unborn_to_new_branch(const struct checkout_opts *opts)
return status;
}
+static void die_expecting_a_branch(const struct branch_info *branch_info)
+{
+ struct object_id oid;
+ char *to_free;
+
+ if (dwim_ref(branch_info->name, strlen(branch_info->name), &oid, &to_free) == 1) {
+ const char *ref = to_free;
+
+ if (skip_prefix(ref, "refs/tags/", &ref))
+ die(_("a branch is expected, got tag '%s'"), ref);
+ if (skip_prefix(ref, "refs/remotes/", &ref))
+ die(_("a branch is expected, got remote branch '%s'"), ref);
+ die(_("a branch is expected, got '%s'"), ref);
+ }
+ if (branch_info->commit)
+ die(_("a branch is expected, got commit '%s'"), branch_info->name);
+ /*
+ * This case should never happen because we already die() on
+ * non-commit, but just in case.
+ */
+ die(_("a branch is expected, got '%s'"), branch_info->name);
+}
+
static int checkout_branch(struct checkout_opts *opts,
struct branch_info *new_branch_info)
{
@@ -1345,6 +1369,14 @@ static int checkout_branch(struct checkout_opts *opts,
!opts->force_detach)
die(_("missing branch or commit argument"));
+ if (!opts->implicit_detach &&
+ !opts->force_detach &&
+ !opts->new_branch &&
+ !opts->new_branch_force &&
+ new_branch_info->name &&
+ !new_branch_info->path)
+ die_expecting_a_branch(new_branch_info);
+
if (new_branch_info->path && !opts->force_detach && !opts->new_branch &&
!opts->ignore_other_worktrees) {
int flag;
@@ -1602,6 +1634,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
opts.no_dwim_new_local_branch = 0;
opts.switch_branch_doing_nothing_is_ok = 1;
opts.accept_pathspec = 1;
+ opts.implicit_detach = 1;
options = parse_options_dup(checkout_options);
options = add_common_options(&opts, options);
@@ -1633,6 +1666,7 @@ int cmd_switch(int argc, const char **argv, const char *prefix)
opts.no_dwim_new_local_branch = 0;
opts.accept_pathspec = 0;
opts.switch_branch_doing_nothing_is_ok = 0;
+ opts.implicit_detach = 0;
options = parse_options_dup(switch_options);
options = add_common_options(&opts, options);
--
2.21.0.548.gd3c7d92dc2
