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

Junio C Hamano [off-list ref] writes:

Jeff King [off-list ref] writes:

quoted

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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?