bug#26795: gnu: emacs-ag: Propagate the-silver-searcher.

[Ludovic Courtès]

Hello Clément,

Clément Lassieur <address@hidden> skribis:

> emacs-ag is mostly unusable via Tramp (except if the
> 'the-silver-searcher' store element is also in the remote system, which
> will never happen if the remote system is not running Guix).
>
> I believe 'the-silver-searcher' should be propagated, and the executable
> should be 'ag' (which is the default value) instead of
> '/gnu/store/...-the-silver-searcher-1.0.2/bin/ag', so that it can be
> found on remote systems.

That makes sense to me.  Christopher Baines wrote it; WDYT Chris?

> This allows emacs-ag to be used on remote systems.
>
> * gnu/packages/emacs.scm (emacs-ag)[inputs]: Remove.  Move THE-SILVER-SEARCHER
> to...
> [propagated-inputs]: ... here.
> [arguments]: Remove 'patch-exec-paths' phase.

[...]

>      (propagated-inputs
>       `(("dash" ,emacs-dash)
> -       ("s" ,emacs-s)))
> +       ("s" ,emacs-s)
> +       ("the-silver-searcher" ,the-silver-searcher)))

I’d suggest writing the rationale for propagation in a comment above.

Thanks,
Ludo’.