Re: display-buffer-change

[Stefan Monnier]

>> I guess I see the following problems:
>> 0 - it's not clear to me why Emacs chooses to split B rather than A.
>> It seems unrelated to the split-height-threshold fix, so we need to look
>> into this before being able to determine how best to fix it.

> Fget_largest_window returns the largest window and B could be that
> window.

So it's not always going to behave this way, it depends on details of the
current layout.  A shift by 1 line can change the result?

>> 1 - since we're in buffer/window A, it would probably be preferable to place
>> buffer C closer rather than further, so in this case after splitting B
>> display-buffer should prefer using the top window for C and the bottom
>> one for B.

> With `split-window' the new window is the lower one, we would lose all
> associations for B if we did that.

I know.  It'a problem.  Independent from the current one.

>> 2 - "dedicated" is mostly meant to cause deletion of the buffer to also
>> cause deletion of the window.  It says nothing about the window having
>> a fixed size or being non-splittable.

> Agreed.

>> 3 - we have window-size-fixed for that.

> David: Could you set that for the buffer of your window B and look
> whether it gives good results.

I don't think that's going to help.  This variable is almost never
used/obeyed :-(

And I don't think it'd help the OP anyway because he doesn't want to go
a configure such things.  And the window shouldn't be fixed-size anyway
(you should still be able to resize it with balance-window, for example).

>> 4 - we don't have window-(un)splittable for that (there's a frame parameter
>> to prevent splitting windows in that frame, tho).

> Earlier I thought about splitting obey a buffer-local value for
> `split-height-threshold'.

That would make a lot of sense.  But I don't think it'd help the OP either
because it's too detailed a configuration.

To get back to the OP's example scenario, starting from 

>>>+-------------+
>>>|             |
>>>|      A      |
>>>|             |
>>>+-------------+
>>>|             |
>>>|      B      |
>>>|             |
>>>+-------------+

Why would

>>>+-------------+
>>>|      A      |
>>>+-------------+
>>>|      C      |
>>>+-------------+
>>>|             |
>>>|      B      |
>>>|             |
>>>+-------------+

be better than

>>>+-------------+
>>>|             |
>>>|      A      |
>>>|             |
>>>+-------------+
>>>|      B      |
>>>+-------------+
>>>|      C      |
>>>+-------------+

and why should it depend on B being dedicated?


        Stefan