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

[Bruno Haible <bruno@clisp.org>]

Thanks for the explanations, Eli.

Eli Zaretskii wrote:
> > Maybe the problem is that the file gets deleted too early, when some parts
> > of Emacs still reference it?
> 
> The buffer which visited that file still exists, and still records the
> name of the file, yes.  And then, when the program writes to another
> file created by another call to make-temp-file, it actually writes to
> a file that some buffer still visits, and in Emacs that triggers a
> prompt to the user to refresh the buffer.

That is a reasonable behaviour for a text editor — but only for file
names that are explicitly controlled by some program or by the user,
not for temporary files.

> The programmer didn't
> expect that because it is natural to expect each call to a function
> that creates a temporary file to create a file under a new name, not
> reuse the same name.

This is an incorrect assumption. Just like socket numbers are randomly
generated in some situations, temp file names are random, and you can't
make assumptions about the resulting file name.

How about storing, as an attribute of the buffer, a boolean that tells
whether the underlying file name is randomly generated (i.e. a temp file),
and query this boolean before prompting to the user to refresh the buffer?

Bruno