bug#62275: 28.2; Changing major mode changes the current text scaling

[Drew Adams]

> > I tried doing this, but it didn't fix the behavior.
> >
> > (put 'text-scale-mode-remapping 'permanent-local t)
> > (put 'text-scale-mode-lighter 'permanent-local t)
> > (put 'text-scale-mode-amount 'permanent-local t)
> 
> You need to do this with face-remapping-alist.

The request is not about _setting_ the remapping of any face or set of faces.

The request is for the effect of text-scaling, from _interactive_ use of 
`text-scale-adjust', to not be removed when the major mode is changed and the 
buffer isn't switched.

IOW, same buffer: keep its current scaling regardless of (only) major-mode 
changes.

> > If there's (also) a good use case for the current behavior then maybe we
> > could have a user option, to choose whether a major-mode change resets
> > the text scale?
> 
> Sounds like creeping featurism to me.  If you want the text size
> larger, then why not customize the default face, and have that done
> once and for all?  Text-scale is by definition a temporary measure.

I don't want the text size larger in general or by default - of any face, let 
alone face `default'.

It's about interactive use of `text-scale-adjust`.  Seems to me its behavior 
should be only buffer-specific and not affected by a major-mode change.  Is 
that not a reasonable behavior to want, if not even generally _expect_?