channels: Record 'guix' channel metadata in (guix config).

Partially fixes <https://bugs.gnu.org/45896>.

* guix/config.scm.in (%channel-metadata): New variable.
* guix/describe.scm (channel-metadata): Use it.
(current-channels): New procedure.
(current-profile-entries): Clarify docstring.
* guix/self.scm (compiled-guix): Add #:channel-metadata and pass it to
'make-config.scm'.
(make-config.scm): Add #:channel-metadata and define '%channel-metadata'
in the generated file.
(guix-derivation): Add #:channel-metadata and pass it to 'compiled-guix'.
* guix/channels.scm (build-from-source): Replace 'name', 'source', and
'commit' parameters with 'instance'.  Pass #:channel-metadata to BUILD.
(build-channel-instance): Adjust accordingly.
* build-aux/build-self.scm (build-program): Add #:channel-metadata
and pass it to 'guix-derivation'.
(build): Add #:channel-metadata and pass it to 'build-program'.
* guix/scripts/describe.scm (display-profile-info): Add optional
'channels' parameter.  Pass it to 'display-profile-content'.
(display-profile-content): Add optional 'channels' parameter and honor
it.  Iterate on CHANNELS rather than on the manifest entries of
PROFILE.
(guix-describe): When PROFILE is #f, call 'current-channels' and pass it
to 'display-profile-info', unless it returns the empty list.

1 files changed, 20 insertions, 5 deletions

diff --git a/guix/self.scm b/guix/self.scm
index 15c8ad4eb9..35fba1152d 100644
--- a/guix/self.scm
+++ b/guix/self.scm
@@ -793,7 +793,9 @@ itself."
     (((labels packages _ ...) ...)
      (cons package packages))))
 
-(define* (compiled-guix source #:key (version %guix-version)
+(define* (compiled-guix source #:key
+                        (version %guix-version)
+                        (channel-metadata #f)
                         (pull-version 1)
                         (name (string-append "guix-" version))
                         (guile-version (effective-version))
@@ -977,6 +979,8 @@ itself."
                                          %guix-package-name
                                          #:package-version
                                          version
+                                         #:channel-metadata
+                                         channel-metadata
                                          #:bug-report-address
                                          %guix-bug-report-address
                                          #:home-page-url
@@ -1070,6 +1074,7 @@ itself."
 (define* (make-config.scm #:key gzip xz bzip2
                           (package-name "GNU Guix")
                           (package-version "0")
+                          (channel-metadata #f)
                           (bug-report-address "bug-guix@gnu.org")
                           (home-page-url "https://guix.gnu.org"))
 
@@ -1083,6 +1088,7 @@ itself."
                                %guix-version
                                %guix-bug-report-address
                                %guix-home-page-url
+                               %channel-metadata
                                %system
                                %store-directory
                                %state-directory
@@ -1125,6 +1131,11 @@ itself."
                    (define %guix-bug-report-address #$bug-report-address)
                    (define %guix-home-page-url #$home-page-url)
 
+                   (define %channel-metadata
+                     ;; Metadata for the 'guix' channel in use.  This
+                     ;; information is used by (guix describe).
+                     '#$channel-metadata)
+
                    (define %gzip
                      #+(and gzip (file-append gzip "/bin/gzip")))
                    (define %bzip2
@@ -1249,11 +1260,14 @@ containing MODULE-FILES and possibly other files as well."
 
 (define* (guix-derivation source version
                           #:optional (guile-version (effective-version))
-                          #:key (pull-version 0))
+                          #:key (pull-version 0)
+                          channel-metadata)
   "Return, as a monadic value, the derivation to build the Guix from SOURCE
-for GUILE-VERSION.  Use VERSION as the version string.  PULL-VERSION specifies
-the version of the 'guix pull' protocol.  Return #f if this PULL-VERSION value
-is not supported."
+for GUILE-VERSION.  Use VERSION as the version string.  Use CHANNEL-METADATA
+as the channel metadata sexp to include in (guix config).
+
+PULL-VERSION specifies the version of the 'guix pull' protocol.  Return #f if
+this PULL-VERSION value is not supported."
   (define (shorten version)
     (if (and (string-every char-set:hex-digit version)
              (> (string-length version) 9))
@@ -1278,6 +1292,7 @@ is not supported."
     (set-guile-for-build guile)
     (let ((guix (compiled-guix source
                                #:version version
+                               #:channel-metadata channel-metadata
                                #:name (string-append "guix-"
                                                      (shorten version))
                                #:pull-version pull-version