bug#24293: 25.1; Display bug: icomplete prompt not visible with icomplete-separator "\n"

[Stefan Monnier]

>> In emacs -Q, eval
>> 
>>   (setq icomplete-separator "\n")
>> 
>> and do
>> 
>>   M-x icomplete-mode <return>
>> 
>> Then, e.g.
>> 
>>   M-x m
>> 
>> The icomplete minibuffer prompt is invisible (bug).
>> 
>> But you see that it's "there" when you hit <left>.  And changing the
>> value of `resize-mini-windows' to nil makes the issue disappear - so I
>> think this is caused by a problem in the display code.
>
> Surprisingly, stepping through the code with a debugger reveals that
> this is not a bug, but (almost) deliberate behavior.  Set
> max-mini-window-height to 0.9, and you will see the entire prompt.

The "prompt" in the above example is not the whole text shown in the
minibuffer but just "M-x m".

> The default value of that variable is 0.25, so Emacs doesn't resize
> mini-windows to more than 1/4th of the height of the frame's root
> window.  And the height required to show the prompt is much larger in
> this case.

No, a single line is sufficient to show "the prompt".


        Stefan