bug#57102: 29.0.50; Peculiar file-name-split edge case

[Lars Ingebrigtsen]

Philip Kaludercic <philipk@posteo.net> writes:

> How sensible is this in the first place?  Shouldn't it rather be
> something like
>
> (file-equal-p (apply #'file-name-concat (file-name-split filename)) filename)
>
> [ which is currently likewise not given ]
>
> Or to put it differently, who does the preceding empty string benefit if
> we ignore the condition mentioned in the docstring?  Are there any
> real-world use-cases?

You need to be able to tell (file-name-split "a/b") => ("a" "b") and
(file-name-split "/a/b") => ("" "a" "b") apart.