bug#36502: Fwd: bug#36502: 27.0.50; infinite loop in file-name-case-insensitive-p

[Ken Brown]

On 7/6/2019 12:14 PM, Eli Zaretskii wrote:
>> From: Ken Brown <kbrown@cornell.edu>
>> Date: Sat, 6 Jul 2019 15:38:14 +0000
>> Cc: "36502@debbugs.gnu.org" <36502@debbugs.gnu.org>
>>
>>> +      && !NILP (Ffile_name_absolute_p (filename)))
>>>        {
>>>          filename = Ffile_name_directory (filename);
>>>          while (NILP (Ffile_exists_p (filename)))
>>>
>>> Or maybe signal an error, either way seems better than just getting stuck.
>>
>> Maybe expand-file-name should signal an error if default-directory is
>> relative?
> 
> That'd not be my first preference.  My first preference would be to
> detect the cases where we are about to loop.  Can we do that?

The only case I can think of where we might loop is the case we're discussing, 
in which expand-file-name fails to return an absolute name.  Noam's patch is 
fine for that case.  But wouldn't it be better to fix expand-file-name so that 
it always returns an absolute name, as it's documented to do?

Ken