bug#6385: A slightly less aggressive fit-window-to-buffer

[martin rudalics]

>> Please post a recipe for reproducing the problem.  I never had any
>> problem with this in practice so I can't tell.
>
> Huh? You yourself said this:
>
>>> I don't know of a simple way to prevent deletion of windows when using
>>> `enlarge-window'.  The problems with `fit-window-to-buffer' are just a
>>> special case of that.
>
> Any you said this:
>
>>>> Deleting other windows when resizing was a misguided feature.
>
> That "misguided feature" is precisely the problem.  You recognize it, so you
> must have sufficient recipes to produce it.

This "misguided feature" is in Emacs ever since I know it.  But you said
that ...

> And unfortunately, I need my code to work in multiple Emacs versions.  It is
> only for Emacs 23 (.1 and .2 and more recent) that this is a problem - I do 
not
> see it happening before 23. So even if you might have a more recent version 
with
> a fix I will still need a workaround for use with Emacs 23.

... and that's what I want a recipe for: A reproducible problem that
does _not_ exist in prior Emacs versions.

> I have not seen that problem arise in releases before Emacs 23, personally.  
The
> code (e.g. for `fit-window-to-buffer') was changed considerably in Emacs 23.  
I
> have supposed that at least part of that code change introduced this 
"misguided
> feature".  Perhaps I'm mistaken about that, but as I say, I do see no such
> problem prior to Emacs 23.
>
> Were you involved with the code changes for this from Emacs 22 to 23?  Did 
those
> changes in fact introduce this "misguided feature", or was it already present?
>
> As I say, I myself see no such "misguided feature" manifest itself prior to 
23.
> Even if the "misguided feature" is theoretically present also before 23, in my
> own, practical experience it shows up only with Emacs 23.

I can answer these questions as soon as you tell me your problem.

> Also, if you have some private code that removes this "misguided feature", why
> does vanilla Emacs itself still suffer from it?  Is your fix not applicable in
> general?  Does it have a downside that prevents you from applying it to 
vanilla
> Emacs?

Yes.  It's a complete rewrite of window resizing in Elisp.
I hardly changed `fit-window-to-buffer', if at all.

> I guess you are confirming that, so long as the binding (e.g. to 1) is in
> effect, it will effectively always prevent window deletion?

No.  The let-binding just allows to make a window as small as one line
in the first place.  But it does not prevent deleting a window.  If you
have a one line window and an nine lines window in a ten lines frame and
you want to enlarge the nine lines window by one line Emacs 23 will
probably delete the one line window.

> So my question still is: if `window-min-height' is 1, then is deletion (due to
> enlarging or shrinking another window) always prevented?

No.

> If not, what are the situations where such a binding is not enough to prevent
> deletion?  And is there, for such situations, another good prevention recipe?
>
> I'm looking for good ways to deal practically with this "misguided feature" as
> it manifests itself in `fit-window-to-buffer'.  Thx.

You can try to replace calls to `enlarge-window' by (appropriately
configured) calls to `adjust-window-trailing-edge'.  Look at the window
balancing code to see how that can be done.

martin