bug#21816: elisp-mode-tests fails on a case-preserving filesystem

[Dmitry Gutov <dgutov@yandex.ru>]

On 11/03/2015 06:04 PM, Juanma Barranquero wrote:

> I'm not sure where you're arguing that
>
> a) xrefs never need to be compared
> b) they are sometimes, but it's ok to use equal and fail in
> case-preserving and case-insensitive systems

Why don't we canonicalize the file name somehow when an xref instance is 
created?

> We're here discussing a real one: a test that needs an ad hoc fix
> because it couldn't just compare two xrefs. Or do you think that writing
> tests isn't a real-life example?

It can be solved as above, for example.

> I'm a bit surprised to be discussing that the basic type offered by an
> infrastructure library as xref needs ways to be compared...

Compared in an impementation-specialized way? Yes, I'd like to see a use 
case.

It's very nontrivial to write a comparison function that would work 
beyond the type you're currently defining (just one xref subtype). 
Hence, its applicability will probably be rather limited.