Subject: [bug#74633] [PATCH v3] ui: Search channels for guix extensions

From: Ludovic Courtès <[email-masked]>
Date: Fri, 10 Jan 2025 20:03:03 +0100

Hello,

Overall it LGTM.  I propose the mostly-cosmetic changes below.

Once thing I overlooked before is that commands will have to live under
/guix/extensions, right?

  (define (commands)
    "Return the list of commands, alphabetically sorted."
    (filter-map source-file-command
                (append (command-files)
                        (append-map command-files
                                    (extension-directories)))))

And likewise in ‘run-guix-command’.

But now, if a channel provides ‘guix/scripts/foo.scm’, the ‘guix help’
command will not show ‘foo’ but the ‘guix foo’ command will effectively
work (which wasn’t the case until now).

Maybe it’s fine actually, I don’t know, but I thought this is worth
mentioning and thinking though.

WDYT?

Ludo’.

diff --git a/guix/describe.scm b/guix/describe.scm
index 90c17084d1..819f0fef74 100644
--- a/guix/describe.scm
+++ b/guix/describe.scm
@@ -27,8 +27,8 @@ (define-module (guix describe)
                                 sexp->channel
                                 manifest-entry-channel)
   #:use-module (srfi srfi-1)
-  #:use-module (srfi srfi-11)
   #:use-module (srfi srfi-34)
+  #:use-module (srfi srfi-71)
   #:use-module (ice-9 match)
   #:export (current-profile
             current-profile-date
@@ -194,10 +194,11 @@ (define (package-path-entries)
 
 (define (append-channels-to-load-path!)
   "Automatically add channels to Guile's search path.  Channels are added to the
-end of the path so they don't override Guix' own modules.  This function ensures
-that channels are only added to the search path once even if it is called
-multiple times."
-  (let-values (((channels-scm channels-go) (package-path-entries)))
+end of the path so they don't override Guix' own modules.
+
+This procedure ensures that channels are only added to the search path once
+even if it is called multiple times."
+  (let ((channels-scm channels-go (package-path-entries)))
     (set! %load-path
           (append %load-path channels-scm))
     (set! %load-compiled-path
diff --git a/guix/ui.scm b/guix/ui.scm
index 05bc99a7e3..d9d7c8469f 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -38,7 +38,8 @@
 (define-module (guix ui)                       ;import in user interfaces only
   #:use-module (guix i18n)
   #:use-module (guix colors)
-  #:use-module (guix describe)
+  #:autoload   (guix describe) (append-channels-to-load-path!
+                                package-path-entries)
   #:use-module (guix diagnostics)
   #:use-module (guix gexp)
   #:use-module (guix sets)
@@ -2200,9 +2201,8 @@ (define (extension-directories)
     (filter file-exists?
             (parse-path
              (getenv "GUIX_EXTENSIONS_PATH")
-             (map
-              (cut string-append <> "/guix/extensions")
-              channels)))))
+             (map (cut string-append <> "/guix/extensions")
+                  channels)))))
 
 (define (commands)
   "Return the list of commands, alphabetically sorted."