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

[Stephen Leake <stephen_leake@stephe-leake.org>]

Juanma Barranquero <lekktu@gmail.com> writes:

> On Tue, Nov 3, 2015 at 3:51 PM, Stephen Leake <
> stephen_leake@stephe-leake.org> wrote:
>
>> What is the use case for these compares, other than tests?
>
> Avoiding duplicates? When adding an xref to a list of xrefs, how do you
> check that isn't it already there?

Currently we don't.

It may come up with some of the multi-backend projects I'm working on,
but in general the xref backends should cover disjoint sets of files, so
it should not happen.

It might happen with non-file xrefs; I haven't used those much.

You asked about "sorting xrefs"; the only sorting that is currently done
is in xref--analyze, which groups xrefs with the same filename. It uses
cl-assoc on the filename, which uses "equal" or "eq" for the string
comparison, I think. It does have a :test parameter we can use to
override that.

So that could fail due to filename case sensitivity; I'll see if I can
construct an example.

However, the fix for this is _not_ a "compare xref" function, since. A
canonicalized file name in the xref would be a fix, as would a "file
name case insensitive compare" function.

-- 
-- Stephe