bug#57129: 29.0.50; Improve behavior of conditionals in Eshell

[Bruno Haible <bruno@clisp.org>]

Eli Zaretskii wrote:
> Looking at your test program, I see that you generate the seconds file
> name without deleting the first one.  When a file by the first
> generated name already exists, gen_tempname will indeed generate a
> different name.  But in the scenario I described, Emacs creates one
> temporary file, uses it, then deletes it, and only after that creates
> another file.

Why would it be important for the second temporary file to bear a different
name, once the first one is gone? I mean, process IDs get reused over time;
socket numbers get reused over time; what is wrong with reusing a file name,
once the older file is gone?

Maybe the problem is that the file gets deleted too early, when some parts
of Emacs still reference it?

Bruno