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

[Brian Kubisiak <brian@kubisiak.com>]

* guix/describe.scm (append-channels-to-load-path!): New function.
* gnu/packages.scm (%package-module-path): Call new function. Remove
the code that the function call replaces.
* guix/ui.scm (extension-directories): Call new function. Search
channels for guix extensions.
* guix/self.scm (compiled-guix)[*core-modules*]: Add 'guile-git' to
the list of extensions.

Change-Id: I53af828dc554485ca28389c9e2653ea6b4fb6b7e
---
 gnu/packages.scm     |  7 ++++---
 gnu/system/image.scm |  2 +-
 guix/describe.scm    | 14 ++++++++++++++
 guix/self.scm        |  1 +
 guix/ui.scm          | 12 +++++++++---
 5 files changed, 29 insertions(+), 7 deletions(-)

diff --git a/gnu/packages.scm b/gnu/packages.scm
index bdd5d21940..ee99dea2ca 100644
--- a/gnu/packages.scm
+++ b/gnu/packages.scm
@@ -148,15 +148,16 @@ (define %package-module-path
   (let* ((not-colon   (char-set-complement (char-set #\:)))
          (environment (string-tokenize (or (getenv "GUIX_PACKAGE_PATH") "")
                                        not-colon))
-         (channels-scm channels-go (package-path-entries)))
+         (channels-scm (package-path-entries)))
     ;; Automatically add channels and items from $GUIX_PACKAGE_PATH to Guile's
     ;; search path.  For historical reasons, $GUIX_PACKAGE_PATH goes to the
     ;; front; channels go to the back so that they don't override Guix' own
     ;; modules.
+    (append-channels-to-load-path!)
     (set! %load-path
-      (append environment %load-path channels-scm))
+      (append environment %load-path))
     (set! %load-compiled-path
-      (append environment %load-compiled-path channels-go))
+      (append environment %load-compiled-path))
 
     (make-parameter
      (append environment
diff --git a/gnu/system/image.scm b/gnu/system/image.scm
index af0f3eb354..e4fdbab634 100644
--- a/gnu/system/image.scm
+++ b/gnu/system/image.scm
@@ -319,7 +319,7 @@ (define gcrypt-sqlite3&co
            (match (package-transitive-propagated-inputs package)
              (((labels packages) ...)
               packages))))
-   (list guile-gcrypt guile-sqlite3)))
+   (list guile-gcrypt guile-git guile-json-4 guile-sqlite3)))
 
 (define-syntax-rule (with-imported-modules* gexp* ...)
   (with-extensions gcrypt-sqlite3&co
diff --git a/guix/describe.scm b/guix/describe.scm
index a4ca2462f4..90c17084d1 100644
--- a/guix/describe.scm
+++ b/guix/describe.scm
@@ -27,6 +27,7 @@ (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 (ice-9 match)
   #:export (current-profile
@@ -34,6 +35,7 @@ (define-module (guix describe)
             current-profile-entries
             current-channels
             package-path-entries
+            append-channels-to-load-path!
 
             package-provenance
             package-channels
@@ -190,6 +192,18 @@ (define (package-path-entries)
                                       "/site-ccache")))
                (current-channel-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)))
+    (set! %load-path
+          (append %load-path channels-scm))
+    (set! %load-compiled-path
+          (append %load-compiled-path channels-go)))
+  (set! append-channels-to-load-path! (lambda () #t)))
+
 (define (package-channels package)
   "Return the list of channels providing PACKAGE or an empty list if it could
 not be determined."
diff --git a/guix/self.scm b/guix/self.scm
index 2652688c71..28239d53f5 100644
--- a/guix/self.scm
+++ b/guix/self.scm
@@ -882,6 +882,7 @@ (define* (compiled-guix source #:key
                     ,(local-file "../guix/store/schema.sql")))
 
                  #:extensions (list guile-gcrypt
+                                    guile-git     ;for (guix git)
                                     guile-json)   ;for (guix swh)
                  #:guile-for-build guile-for-build))
 
diff --git a/guix/ui.scm b/guix/ui.scm
index 87a448bf72..05bc99a7e3 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -38,6 +38,7 @@
 (define-module (guix ui)                       ;import in user interfaces only
   #:use-module (guix i18n)
   #:use-module (guix colors)
+  #:use-module (guix describe)
   #:use-module (guix diagnostics)
   #:use-module (guix gexp)
   #:use-module (guix sets)
@@ -2194,9 +2195,14 @@ (define* (command-files #:optional directory)
 
 (define (extension-directories)
   "Return the list of directories containing Guix extensions."
-  (filter file-exists?
-          (parse-path
-           (getenv "GUIX_EXTENSIONS_PATH"))))
+  (append-channels-to-load-path!)
+  (let ((channels (package-path-entries)))
+    (filter file-exists?
+            (parse-path
+             (getenv "GUIX_EXTENSIONS_PATH")
+             (map
+              (cut string-append <> "/guix/extensions")
+              channels)))))
 
 (define (commands)
   "Return the list of commands, alphabetically sorted."

base-commit: a76f2d5927c86e4a76a1d3b49c1a37054612f6c0
prerequisite-patch-id: 7835a4f0fbc5e19dcb65195bc9fb69c656915ee1
-- 
2.47.1