04/07: channels: Gracefully report the lack of a 'guix' channel.

[guix-commits]

civodul pushed a commit to branch master
in repository guix.

commit ab6025b52cec792312d465107e9b86d7900c5f93
Author: Ludovic Courtès <address@hidden>
Date:   Sun Jan 20 18:11:11 2019 +0100

    channels: Gracefully report the lack of a 'guix' channel.
    
    * guix/channels.scm (channel-instance-derivations): Raise an '&message'
    condition when CORE-INSTANCE is #f.
---
 guix/channels.scm | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/guix/channels.scm b/guix/channels.scm
index eb56c82..e588d86 100644
--- a/guix/channels.scm
+++ b/guix/channels.scm
@@ -28,10 +28,15 @@
   #:use-module (guix derivations)
   #:use-module (guix store)
   #:use-module (guix i18n)
+  #:use-module ((guix utils)
+                #:select (source-properties->location
+                          &error-location))
   #:use-module (srfi srfi-1)
   #:use-module (srfi srfi-2)
   #:use-module (srfi srfi-9)
   #:use-module (srfi srfi-11)
+  #:use-module (srfi srfi-34)
+  #:use-module (srfi srfi-35)
   #:autoload   (guix self) (whole-package make-config.scm)
   #:autoload   (guix inferior) (gexp->derivation-in-inferior) ;FIXME: circular 
dep
   #:use-module (ice-9 match)
@@ -345,6 +350,17 @@ INSTANCES."
                    (build-channel-instance instance core deps)))
              instance))
 
+  (unless core-instance
+    (let ((loc (and=> (any (compose channel-location channel-instance-channel)
+                           instances)
+                      source-properties->location)))
+      (raise (apply make-compound-condition
+                    (condition
+                     (&message (message "'guix' channel is lacking")))
+                    (if loc
+                        (list (condition (&error-location (location loc))))
+                        '())))))
+
   (mapm %store-monad instance->derivation instances))
 
 (define (whole-package-for-legacy name modules)