Re: [PATCH/RFC] clone: report duplicate entries on case-insensitive filesystems

["Torsten Bögershausen" <tboegi@web.de>]

On 2018-08-02 15:43, Duy Nguyen wrote:
> On Wed, Aug 1, 2018 at 11:20 PM Junio C Hamano <gitster@pobox.com> wrote:
>>
>> Junio C Hamano <gitster@pobox.com> writes:
>>
>>> Jeff King <peff@peff.net> writes:
>>>
>>>>> Presumably we are already in an error codepath, so if it is
>>>>> absolutely necessary, then we can issue a lstat() to grab the inum
>>>>> for the path we are about to create, iterate over the previously
>>>>> checked out paths issuing lstat() and see which one yields the same
>>>>> inum, to find the one who is the culprit.
>>>>
>>>> Yes, this is the cleverness I was missing in my earlier response.
>>>>
>>>> So it seems do-able, and I like that this incurs no cost in the
>>>> non-error case.
>>>
>>> Not so fast, unfortunately.
>>>
>>> I suspect that some filesystems do not give us inum that we can use
>>> for that "identity" purpose, and they tend to be the ones with the
>>> case smashing characteristics where we need this code in the error
>>> path the most X-<.
>>
>> But even if inum is unreliable, we should be able to use other
>> clues, perhaps the same set of fields we use for cached stat
>> matching optimization we use for "diff" plumbing commands, to
>> implement the error report.  The more important part of the idea is
>> that we already need to notice that we need to remove a path that is
>> in the working tree while doing the checkout, so the alternative
>> approach won't incur any extra cost for normal cases where the
>> project being checked out does not have two files whose pathnames
>> are only different in case (or checking out such an offending
>> project to a case sensitive filesytem, of course).
>>
>> So I guess it still _is_ workable.  Any takers?
> 
> OK so we're going back to the original way of checking that we check
> out the different files on the same place (because fs is icase) and
> try to collect all paths for reporting, yes?

I would say: Yes.

> I can give it another go
> (but of course if anybody else steps up, I'd very gladly hand this
> over)
> 

Not at the moment.