Re: feature/package-vc has been merged

[Philip Kaludercic]

Eli Zaretskii <eliz@gnu.org> writes:

>> > Which steps are those, and why do we have to do it manually?
>> 
>> Let us assume `default-directory' is (locate-user-emacs-file "elpa").
>> If I run "M-! git clone https://some.git.host.com/path/to/repo/foo.git";,
>> then I'll just have a directory called "foo", right?  If I want to byte
>> compile the files I'd e.g. have to open foo in Dired, mark all Emacs
>> Lisp files, byte compile them, then run something like
>> `make-directory-autoloads' myself.  Then I'd have to find the main file,
>> check the dependency list and run M-x package-install on every one that
>> is missing, again one-by-one.
>> 
>> You don't have to do this for `package-install', because it invokes
>> `package-unpack' that takes care of those details.  As
>> package-vc-install doesn't use prepared tarballs, the equivalent process
>> is a bit different (thus we have `package-vc-unpack'), but the intention
>> is the same.  Bundle all the repetitive task into a single command.
>
> OK, but my question was why all of this gets magically done when you
> clone the repository outside ~/.emacs.d/elpa, but does not get done
> when you clone it inside?  I thought this is what you were alluding to
> when I asked why not clone into ~/.emacs.d.

Oh no, I'm sorry if I implied this somehow.  This is neither the case in
or outside of ~/.emacs.d/elpa.  Somehow, someone has to do all of this.
And one someone is package-vc.

>> >   (if (fboundp 'normal-top-level-add-subdirs-to-load-path)
>> >       (normal-top-level-add-subdirs-to-load-path))
>> >
>> > Example of directories which need this is the site-lisp directory.
>> 
>> I was not familiar with this function.
>> 
>> > Why cannot we do something like this in this case?
>> 
>> I would have to try this out, but my worry is that in some cases this
>> could add too many non-lisp directories.
>
> The function can be easily extended to only add directories in which
> we have *.el files.

This might work well enough most of the time, but I don't think we
always want this.

>> It still seems more elegant to encode what the lisp directory is in the
>> package description.
>
> You consider manual configuration of a package to be more elegant than
> automatically finding the directories to put on load-path?

Eh, I am not sure what we are talking about anymore :/ I think it is
best for me to reiterate.  Both elpa.git and nongnu.git have package
specifications in "elpa-packages", that among other things may contain
properties indicating what directory the lisp files are located in.
elpa-admin.el uses this information to prepare the tarballs for
distribution.

These package specifications are now also published in a way that
package-vc can process them.  For GNU ELPA you can find these here:
https://elpa.gnu.org/packages/elpa-packages.eld.  After cloning a
package repository, package-vc can use the `:lisp-dir' property from a
package specification to figure out what directory is to be added to the
load-path, where the files are that should be byte-compiled,
auto-loaded, etc.

I am proposing we make use of this available information instead of
guessing or making broad assumptions like that all lisp code is of
interest.