bug#12145: Fix causes problems with other processes

[Michael Albinus <michael.albinus@gmx.de>]

Thomas Koch <thomas@koch.ro> writes:

Hi Thomas,

> The problem identified by the first backtrace still exists even with the patch for this bug from 2012. It happens, when find-name-dired on a remote system returns very fast (or maybe when the output is very short?), e.g. when called on an empty directory.
>
> The function `find-dired` starts a background shell process:
>
>     (shell-command (concat args "&") (current-buffer))
>
> A few lines later, the function asks for the process and uses it without any error checking:
>
>     (let ((proc (get-buffer-process (current-buffer))))
>       (set-process-filter proc (function find-dired-filter))
>
> I assume, that get-buffer-process returns nil when the process has already terminated.

Good analysis, thanks. I'll play with this, hopefully I can reproduce.

On a first glance (w/o testing), something like this could work:

(let (proc)
  (while (not (process-alive-p (setq proc (get-buffer-process (current-buffer))))))
  (set-process-filter proc (function find-dired-filter))
  ...)

> I don't have an idea about the second backtrace yet. But given that the code of find-name-dired seems problematic, this might be a motivation to not search for a fix in tramp but in find-name-dired (and called functions).

I'll check.

Best regards, Michael.