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

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

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Stephen Leake <stephen_leake@stephe-leake.org>
>> Cc: Juanma Barranquero <lekktu@gmail.com>, Eli Zaretskii
>> <eliz@gnu.org>, 21816@debbugs.gnu.org
>> Date: Tue, 03 Nov 2015 13:54:21 -0600
>> 
>>    If the file name identifies an existing file, convert the file name
>>    casing to match the actual file name casing. If not, no case
>>    conversion is done.
>
> For existing files we have file-equal-p, which is more general.  

You missed the context; we have switched from discussing how to compare
file names to how to canonicalize a file name, in order to simplify the
comparison.

The rationale here is that it is not possible/easy to always know
whether the string at hand is a file name, but it is always possible (or
at least much easier) to ensure that an xref contains a canonical file
name.

Part of the definition of "canonical file name" must also be:

    Two names for an existing file will convert to canonical filenames
    that will return t from `equal-string'".

-- 
-- Stephe