bug#41821: 28.0.50; read-directory-name in vc commands should provide defaults from projects

[Dmitry Gutov]

Hi Eli,

On 01.07.2020 17:42, Eli Zaretskii wrote:
> Like you, Dmitry, I'm a bit uneasy with mixing the two sets of
> features.  We should decide on some concept and try to stick to it;
> right now, it seems to me that we prefer to have specialized commands
> in project.el rather than inject project.el-specific nits into
> commands outside project.el, which I think could be a slippery slope.

In my previous message I drew a line, of sorts, where I think it's okay 
to suggest directories to search in in rgrep from known project roots. I 
do think it's okay.

I'm not sure if I understand your position, because you say you agree, 
but then make a one-directional statement.

> Why isn't that a better approach?  I don't think it's wise to blur the
> difference between using project.el features and the VC back-end
> features that support them.  If someone wants to use project.el in VC
> commands, let them use project.el commands, not VC commands.  That
> way, Emacs will know that some kind of project is being worked on, and
> could offer more targeted support for such users.

Not sure that's going to result in optimal user experience. After all, 
simply having a copy of every command, but acting on a project, would 
make it 2x the number of commands.

And project-rgrep, on the other hand, would probably search the current 
project root without prompting. Unlike the proposed change to rgrep, 
which only makes it a suggestion.

Another long-term violation of your idea is the default definition of 
xref-backend-references. It uses the current project. You could say that 
mixes up abstractions as well, but it's just too handy to implement this 
way.