[bug#54307] [PATCH 1/2] ui: 'show-what-to-build' highlights "The following [...] will be built".

["Ludovic Courtès" <ludo@gnu.org>]

* guix/colors.scm (highlight/warn): New procedure.
* guix/ui.scm (show-what-to-build): Use 'highlight/warn' when displaying
what would/will be built.
---
 guix/colors.scm |  4 +++-
 guix/ui.scm     | 24 ++++++++++++++----------
 2 files changed, 17 insertions(+), 11 deletions(-)

diff --git a/guix/colors.scm b/guix/colors.scm
index 3031f54799..ae0a583d94 100644
--- a/guix/colors.scm
+++ b/guix/colors.scm
@@ -2,7 +2,7 @@
 ;;; Copyright © 2013, 2014 Free Software Foundation, Inc.
 ;;; Copyright © 2018 Sahithi Yarlagadda <sahi@swecha.net>
 ;;; Copyright © 2018 Ricardo Wurmus <rekado@elephly.net>
-;;; Copyright © 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2017, 2018, 2019, 2022 Ludovic Courtès <ludo@gnu.org>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -31,6 +31,7 @@ (define-module (guix colors)
 
             colorize-string
             highlight
+            highlight/warn
             dim
 
             color-rules
@@ -143,6 +144,7 @@ (define (coloring-procedure color)
         str)))
 
 (define highlight (coloring-procedure (color BOLD)))
+(define highlight/warn (coloring-procedure (color BOLD MAGENTA)))
 (define dim (coloring-procedure (color DARK)))
 
 (define (colorize-matches rules)
diff --git a/guix/ui.scm b/guix/ui.scm
index 238952723e..8e4e3e2dfc 100644
--- a/guix/ui.scm
+++ b/guix/ui.scm
@@ -1031,12 +1031,14 @@ (define display-download-size?
     ;; Unfortunately, this is hardly avoidable for proper i18n.
     (if dry-run?
         (begin
-          (unless (zero? verbosity)
+          (unless (or (zero? verbosity) (null? build))
             (format (current-error-port)
-                    (N_ "~:[The following derivation would be built:~%~{   ~a~%~}~;~]"
-                        "~:[The following derivations would be built:~%~{   ~a~%~}~;~]"
-                        (length build))
-                    (null? build) (map colorized-store-item build)))
+                    (highlight/warn
+                     (N_ "The following derivation would be built:~%"
+                         "The following derivations would be built:~%"
+                         (length build))))
+            (format (current-error-port) "~{  ~a~%~}"
+                    (map colorized-store-item build)))
           (cond ((>= verbosity 2)
                  (if display-download-size?
                      (format (current-error-port)
@@ -1082,12 +1084,14 @@ (define display-download-size?
                              (null? download) (length download))))))
 
         (begin
-          (unless (zero? verbosity)
+          (unless (or (zero? verbosity) (null? build))
             (format (current-error-port)
-                    (N_ "~:[The following derivation will be built:~%~{   ~a~%~}~;~]"
-                        "~:[The following derivations will be built:~%~{   ~a~%~}~;~]"
-                        (length build))
-                    (null? build) (map colorized-store-item build)))
+                    (highlight/warn
+                     (N_ "The following derivation will be built:~%"
+                         "The following derivations will be built:~%"
+                         (length build))))
+            (format (current-error-port) "~{  ~a~%~}"
+                    (map colorized-store-item build)))
           (cond ((>= verbosity 2)
                  (if display-download-size?
                      (format (current-error-port)
-- 
2.34.0