[Bug: 21.4.21] dired complains about an unrelated directory

[Michael Sperber]

Mike Kupfer <mike.kupfer at sun.com> writes:

> I'm currently (as I type this in) unable to visit a directory using
> dired.  It complains "operation not supported" on some other directory
> that's totally unrelated to the one I want to visit.  I enabled
> debug-on-error and got this backtrace:
>
> Debugger entered--Lisp error: (file-error "Finding truename" "Operation not supported on transport endpoint" "/net/sfwnv/export/nv/")
>   file-truename("/net/sfwnv/export/nv/")
>   apply(file-truename "/net/sfwnv/export/nv/")
>   dired-handler-fn(file-truename "/net/sfwnv/export/nv/")
>   file-truename("/net/sfwnv/export/nv/")
>   dired-directory-truename("/net/sfwnv/export/nv/")
>   dired-find-buffer-nocreate("/export/kupfer/tonic/stevel/" nil)
>   dired-internal-noselect("/export/kupfer/tonic/stevel/" nil)
>   dired-noselect("/export/kupfer/tonic/stevel" nil)
>   #<compiled-function (dirname &optional switches) "...(7)" [switches dirname switch-to-buffer dired-noselect] 4 ("/net/athyra/usr/local/lib/xemacs/xemacs-packages/lisp/dired/dired.elc" . 33956) (dired-read-dir-and-switches "")>("/export/kupfer/tonic/stevel" nil)
>   call-interactively(dired)
>
>
> /export/kupfer/tonic/stevel/ is the directory I want to visit.
> /net/sfwnv/export/nv/ is an NFS directory that I had tried to visit
> earlier in the day but couldn't (permissions problem).
>
> I haven't looked at the relevant dired code, but I'm hypothesizing that
> it's trying to reclaim resources associated with the directory I
> couldn't visit.  The buffer for that directory has this text:
>
>   /net/sfwnv/export/nv:
>   ls: error reading directory /net/sfwnv/export/nv/.: Permission denied
>   total 0
>
> Let's try killing that buffer...  done.  And now dired lets me visit
> /export/kupfer/tonic/stevel/.

It's trying to see if it can re-use the earlier buffer for the new dired
command you're doing, and, in the process of that, tries to find the
truename of the directory of that earlier buffer.  You can set
`find-file-compare-truenames' and `dired-find-file-compare-truenames' to
nil to prevent it from doing that.

-- 
Cheers =8-} Mike
Friede, Völkerverständigung und überhaupt blabla