I've pushed my experiment to the `wip-filesearch' branch.

As of this writing it is not automatically triggered by "guix build".
To test it:

- Load the module from a REPL.

- Run

--8<---------------cut here---------------start------------->8---
  (test-index-git)
--8<---------------cut here---------------end--------------->8---

  You should get a database at ~/.cache/guix/files.db.

- Run

--8<---------------cut here---------------start------------->8---
  (format-search (search-file-package "git perl5"))
--8<---------------cut here---------------end--------------->8---

  to get some search results.

- Run

--8<---------------cut here---------------start------------->8---
  (persist-all-local-packages)
--8<---------------cut here---------------end--------------->8---

  to build the database for all your local files.  Warning, this takes
  some 30 seconds on my machine, could take minutes if you has a
  spinning drive or an old processor.

I'll be away for a couple of days, feel free to experiment and send me
some feedback in the meantime.

What remains to be done:

- Automatically index "guix build" result in database.
  Any idea where I can trigger the indexing from a "guix build"?

- Sync the database data from a substitute server.  Any pointer would be
  appreciated :)

Cheers!

-- 
Pierre Neidhardt
https://ambrevar.xyz/