bug#50178: 28.0.50; Size of echo area does not account for line-spacing

["Óscar Fuentes" <ofv@wanadoo.es>]

Eli Zaretskii <eliz@gnu.org> writes:

> And why is that a problem?  Emacs displays partially visible lines at
> end of window in many cases; as long as the list of completion
> candidates is long enough, you cannot see all of them anyway.
>
> Or maybe you have a specific recipe in mind where this works
> incorrectly, in which case please show that recipe.

There are some packages that works displaying a certain number of lines
on the echo area (ido-grid-mode, for instance.) They set
max-mini-window-height to an integer and expect that Emacs will take
care of resizing the echo area accordingly, if possible. If the
resulting echo area is not tall enough, there is a problem.

IMO max-mini-window-height, when set to an integer, should mean "I want
this many lines", as it does when line-spacing is nil. Otherwise every
one of those packages must implement the heuristics for taking into
account `line-spacing' and any other present and future variable that
might affect the number of lines visible on the echo area.