Re: [PATCH 2/2] worktree: reject empty string

["René Scharfe" <l.s.r@web.de>]

On 8/2/26 8:26 AM, René Scharfe wrote:
> On 7/25/26 1:19 PM, Matthias AÃhauer via GitGitGadget wrote:
>> 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)
> 
> Hmm, on my machine, with or without this patch:
> 
>    $ git worktree add ""
>    Preparing worktree (new branch '')
>    fatal: '' is not a valid branch name
>    hint: See 'git help check-ref-format'
>    hint: Disable this message with "git config set advice.refSyntax false"
This hits the BUG by passing the empty string directly to add_worktree():

   $ git worktree add "" HEAD
   Preparing worktree (detached HEAD a97fcc37c2)
   BUG: builtin/worktree.c:498: How come '' becomes empty after sanitization?

René