Re: Text Properties And Buffer Modification

[Eli Zaretskii <eliz@gnu.org>]

> From: "T.V Raman" <raman@google.com>
> Date: Tue, 04 Dec 2018 15:39:31 -0800
> 
> At present, modifying text properties (adding, removing or changing
> properties) markes the buffer as  modified.
> Since property changes are mostly cosmetic, is there a good reason why
> this is so?

Because text properties are part of the buffer text: if you copy some
of the text into another place, the properties go there as well.

> Given the present state of buffer-modified status with respect to
> text-properties, one  has to be fairly careful e.g.
> naively writing 
> (with-silent-modifications (put-text-property ...))
> will work *most of the time* except when you say something like:
> (with-silent-modifications 
>   (put-text-property beg end 'face 'bold other-buffer))
> 
> you actually need to write this:
> 
> (with-silent-modifications 
>   (with-current-buffer other-buffer 
>     (put-text-property beg end 'face 'bold other-buffer)))

You could instead simply make the target buffer not modified after you
are done changing the properties, e.g. by using set-buffer-modified-p.