guix describe: Display channel introductions and add 'channels-sans-intro'.

* guix/scripts/describe.scm (%available-formats): Add "channels-sans-intro".
(channel->sexp): Add #:include-introduction?.  Emit CHANNEL's intro if
INCLUDE-INTRODUCTION? is true and CHANNEL has an introduction.
(channel->json): Include CHANNEL's introduction, if any.
(channel->recutils): Likewise.
(display-profile-info): Add 'channels-sans-intro' case.
* doc/guix.texi (Invoking guix describe): Add introduction in example.
Add 'channels-sans-intro' case.

1 files changed, 12 insertions, 1 deletions

diff --git a/doc/guix.texi b/doc/guix.texi
index 67c86de4b6..c3dd977860 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -4608,7 +4608,12 @@ $ guix describe -f channels
         (name 'guix)
         (url "https://git.savannah.gnu.org/git/guix.git")
         (commit
-          "e0fa68c7718fffd33d81af415279d6ddb518f727")))
+          "e0fa68c7718fffd33d81af415279d6ddb518f727")
+        (introduction
+          (make-channel-introduction
+            "9edb3f66fd807b096b48283debdcddccfea34bad"
+            (openpgp-fingerprint
+              "BBB0 2DDF 2CEA F6A8 0D1D  E643 A2A0 6DF2 A33A 54FA")))))
 @end example
 
 @noindent
@@ -4634,6 +4639,12 @@ produce human-readable output;
 produce a list of channel specifications that can be passed to @command{guix
 pull -C} or installed as @file{~/.config/guix/channels.scm} (@pxref{Invoking
 guix pull});
+@item channels-sans-intro
+like @code{channels}, but omit the @code{introduction} field; use it to
+produce a channel specification suitable for Guix version 1.1.0 or
+earlier---the @code{introduction} field has to do with channel
+authentication (@pxref{Channels, Channel Authentication}) and is not
+supported by these older versions;
 @item json
 @cindex JSON
 produce a list of channel specifications in JSON format;