bug#34038: 26.1; set-window-start sometimes fails to set window start

[Eli Zaretskii]

On January 13, 2019 10:40:20 AM GMT+02:00, martin rudalics <rudalics@gmx.at> 
wrote:
>  > This indeed seems to be a critical factor: an empty last line that
>  > appears as the first line of the window.
> 
> I think I now distilled a fairly simply recipe to watch the problem.
> Load the attached file with emacs -Q and type C-.
> 
> Note that *scratch* contains no empty line when finally displayed.
> Also, here C-. displays the desired result with window-start at
> point-max for a short moment before making the buffer fully visible.
> Setting 'scroll-conservatively' to 101 fixes the problem.
> 
> martin

There's no bug here: Emacs by default avoids starting a window's display at 
EOB.  Scroll-conservatively overrides that.