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

[Zihao Zhu <cjpeople2013@gmail.com>]

If I have a project.el based plugin,  and  I wanna use them in a 
directory not under VC. Add an mark to force project.el work is easier 
than modify the source of plugin or initialize VC system.

And this  can also be used as a side solution to use project.el in 
unsupported VCed project in Emacs (AFAIK, P4(Perforce) is not supported 
by vc.el).

IMO, a plain project is like a transient project.

On 2020/5/28 下午8:35, Dmitry Gutov wrote:
> Hi!
>
> On 28.05.2020 06:32, Zhu Zihao wrote:
>> This patch add support for "plain project" in project.el. Plain 
>> project is a
>> kind of project without any VC backend but should be.
>>
>> To mark a directoy as project, put an empty magic file .emacs-project 
>> under the
>>
>> directory, and project.el should be responsible for it.
>
> Is that really a good idea?
>
> I mean, you of course can set up a project type like that yourself.
>
> But if it's included in project.el, it means we're taking it 
> seriously. And there's no way to specify the ignored files, say. And 
> file enumeration will inevitably be slower than in VC-based projects.
>
> Do you have a lot of projects that aren't backed by VC repositories?