Re: Why does saving a buffer to a new file clear local variables?

[Michael Heerdegen <michael_heerdegen@web.de>]

Patrick Nicodemus <gadget142@gmail.com> writes:

> If I create a new buffer like (get-buffer-create "tmpbuf"),
> switch to the buffer, and execute the commands
> (make-variable-buffer-local "abc")
> (setq abc 3)
> and then save the buffer to, say, "tmpbuf", then abc becomes nil.
> Why is this the case?
> Is this behavior documented anywhere?
> I checked that it doesn't change the major mode. It is "Fundamental" before
> and after saving.

I recall we had a very similar question not long ago.  I think Eli gave
an answer, and it was like that this situation counts as visiting a
file, and visiting a file by default clears all local bindings via
`normal-mode'.

There are ways to modify this behavior - in your scenario, turning
`change-major-mode-with-file-name' off prevents losing your local
binding.

Giving a variable a non-nil `permanent-local' property also would have
this effect - see `kill-all-local-variables's docstring.  But the
details depend on the use case.


Michael.