bug#53776: Modeline indicator when using define-minor-mode

[Stephen Berman]

On Fri, 04 Feb 2022 11:55:45 +0000 goncholden via "Bug reports for GNU Emacs, 
the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org> wrote:

> Have been using define-minor-mode and noticed that when setting the
> modeline indicator, the text is appended with no space between other
> modeline indicators. Is this how :lighter is supposed to work?

Yes, the lack of a space is in the definition of `mode-line-modes':

  `(:propertize ("" minor-mode-alist)

I guess the reason is that you can have multiple minor mode lighters and
providing a space between each would complicate the definition of
`mode-line-modes', so that's the job of the minor mode definition
itself:

> (define-minor-mode rich-minor-mode
> "This is the docstring."
> :lighter "rich"

So you should do this: :lighter " rich"

Steve Berman