bug#41572: 28.0.50; [PATCH] Support plain project marked with file .emacs-project

[Eli Zaretskii]

> Cc: "Philip K." <philipk@posteo.net>, Rudi Schlatte <rudi@constantly.at>,
>  Augusto Stoffel <arstoffel@gmail.com>, Zhu Zihao <cjpeople2013@gmail.com>,
>  Theodor Thornhill <theo@thornhill.no>,
>  Daniel Martín <mardani29@yahoo.es>,
>  Eric Abrahamsen <eric@ericabrahamsen.net>,
>  João Távora <joaotavora@gmail.com>,
>  Manuel Uberti <manuel.uberti@inventati.org>, Juri Linkov <juri@linkov.net>,
>  Rudolf Adamkovič <salutis@me.com>
> Date: Sat, 26 Nov 2022 03:49:36 +0200
> From: Dmitry Gutov <dgutov@yandex.ru>
> 
> Does this work for everybody?

Hard to say, because:

> +(defcustom project-vc-extra-root-markers nil
> +  "List of additional \"markers\" to signal project roots.
> +
> +A marker is either a base file name or a glob pattern for such.
> +
> +These will be used in addition to regular directory markers such
> +as .git, .hg, and so on, dependent on the value of
> +`vc-handled-backends'.

"These will be used" how?  This crucial information is sorely missing from
this description.  Likewise, how "markers" that are not files are used and
are useful?

>                         They are most useful when a VC project
> +has subdirectories inside it that need to be considered as
> +separate projects, but still use the parent's ignore rules and
> +general behaviors.

How are "markers" useful in this scenario?

> +It can also be used for projects outside of VC repositories.
> +Their behavior will still obey the relevant variables, such as
> +`project-vc-ignores' or `project-vc-name'."

And in this one?

IOW, please describe the main ideas of this approach instead of relying on
use immediately gleaning that from a patch with incomplete documentation.

TIA