Flymake, compilation-mode lighters very noisy

[Yuri Khan <yurivkhan@gmail.com>]

Hello,

I was fiddling with my Python development environment to start using
python-language-server, and settled on Eglot as a novice-friendly LSP
client.

Now, one side effect of Eglot is that it enables Flymake unconditionally.

Not that I mind, no; actually, I find it very convenient that
potential bugs are highlighted as soon as I create them.

What I do mind, though, is these two menacing eyes staring at me from
the mode line.

    … (Python yas WS SP Flymake[0 0] Projectile[…] ARev ElDoc)
                               ↗   ↖
                bold bright red     bold yellow

(seriously though, I just find bright/high-constrast spots in my
peripheral vision distracting.)

Compilation-mode has the same issue, with as many as four eyes:

    … (Compilation:exit [0] [0 0 0])
                  ↗     ↗   ↗  ↑  ↖
                  green   red  |   green
                             yellow

I understand the motivation: provide instant error, warning and info
counters, and use color coding to avoid having to explain which
counter is for which severity level.

However, I wonder if zero counters could be skipped in the mode line.
After all, they have nothing to say; they shouldn’t be yelling about
that. IMHO.

In the case of compilation-mode, I can redefine the
‘compilation-mode-line-errors’ variable easily enough; it’s just a
mode line fragment referencing a few variables.

Flymake, though, delegates the work to the function
‘flymake--mode-line-format’, which is pretty involved (110 lines of
code). Not much I can do with that, as a user, except copy-pasting
that function into my init.el with a minor change.

Thoughts?