[PATCH 2/2] worktree: reject empty string

["Matthias Aßhauer via GitGitGadget" <gitgitgadget@gmail.com>]

From: =?UTF-8?q?Matthias=20A=C3=9Fhauer?= <mha1993@live.de>

`git worktree add ""` errors out with the message `BUG: How come ''
becomes empty after sanitization?`, but not due to a bug in the
sanitization code. An empty string should remain empty during
sanitization. Instead reject the argument as invalid user input,
if it's already empty before sanitization.

Signed-off-by: Matthias Aßhauer <mha1993@live.de>
---
 builtin/worktree.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/builtin/worktree.c b/builtin/worktree.c
index d8188035db..113dbf98d3 100644
--- a/builtin/worktree.c
+++ b/builtin/worktree.c
@@ -496,6 +496,8 @@ static int add_worktree(const char *path, const char *refname,
 		die(_("invalid reference: %s"), refname);
 
 	name = worktree_basename(path, &len);
+	if (!len)
+		die(_("the empty string is not a valid worktree"));
 	strbuf_add(&sb, name, path + len - name);
 	sanitize_refname_component(sb.buf, &sb_name);
 	if (!sb_name.len)
-- 
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