bug#57556: 28.1; Eshell not finding executables in PATH when tramp-integration loaded

[Jim Porter]

On 10/1/2022 1:25 PM, Michael Albinus wrote:
> Jim Porter <jporterbugs@gmail.com> writes:
>
> I didn't install your patches, but I gave them a cursory review.

Thanks for taking a look.

> >    set ENV_VAR value
> >    set #'lisp-var value
>
> Well, in Elisp the #'symbol read syntax is used for function names, see
> (info "(elisp) Special Read Syntax")
>
> So it is surprising to see it used for variable names.

Yeah, it took me quite a while to realize that Eshell's meaning of 
#'symbol is different from Elisp's. I recently added some documentation 
in the Eshell manual to (hopefully) clarify the potential confusion.

> > Patch #4: Make $PATH a variable alias
> > ----------------------------------------
> >
> > This stores the $PATH in an alist indexed by host, similar to
> > 'grep-host-defaults-alist'. For consistency, it now derives its value
> > from '(exec-path)' everywhere (formerly, it used '(getenv "PATH") for
> > local hosts and '(exec-path)' for Tramp).
>
> Again, no possibility to use connection-local variables? You use them
> already by calling (path-separator) ...

I'll take a look at doing that. As I understand it, connection-local 
variables are cleared if the associated connection gets cleaned up, 
right? I wonder if that would be the right thing to do. For example, if 
I cd into a remote host in Eshell, then update Eshell's $PATH for that 
host, then clean up the connection, should the $PATH be reset to the 
default for that host? I'm really not sure...

> > -(defun eshell-get-path ()
> > +(make-obsolete-variable 'eshell-path-env 'eshell-get-path "29.1")
>
> I guess you mean 'eshell-host-path-env' as CURRENT-NAME.

I wanted to say, "Instead of using the variable 'eshell-path-env', call 
the function 'eshell-get-path'." Maybe that's not the right way to 
indicate that though.

> > +(defun eshell-get-path (&optional local-part)
> > +  (let* ((remote (file-remote-p default-directory))
> > +         (path (cdr (eshell-get-path-assq remote t))))
> > +    (when (and (eshell-under-windows-p)
> > +               (not remote))
> > +      (push "." path))
> > +    (if (and remote (not local-part))
> > +        (mapcar (lambda (x) (concat remote x)) path)
>
> Why not file-name-concat?

Good point. I'd forgotten to update that when copying that bit out of 
'eshell-parse-colon-path'.