From c28c9383afeea102f43aa40ea466bba4e32516bf Mon Sep 17 00:00:00 2001
From: Maxime Devos <maximedevos@telenet.be>
Date: Fri, 9 Apr 2021 17:17:01 +0200
Subject: [PATCH 2/2] lint: Extend 'compiler-for-target' to detect CXX=g++.

* guix/lint.scm (check-compiler-for-target): Detect "CXX=g++".
* tests/lint.scm
  ("compiler-for-target: no warnings (cxx-for-target)")
  ("compiler-for-target: warning (hardcoded CC=g++)"): New test cases.
---
 guix/lint.scm  | 33 +++++++++++++++++++++++----------
 tests/lint.scm | 19 ++++++++++++++++++-
 2 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/guix/lint.scm b/guix/lint.scm
index bf9acb40be..1f32ff8393 100644
--- a/guix/lint.scm
+++ b/guix/lint.scm
@@ -1366,16 +1366,29 @@ host compiler."
                             ;; support all patterns.
                             (make-flags/evaluated
                              (false-if-exception
-                              (evaluate-argument make-flags package)))
-                            (cc (any (lambda (x)
-                                       (and (string-prefix? "CC=" x)
-                                            (substring x 3)))
-                                     make-flags/evaluated)))
-                   (and cc (string=? cc "gcc")
-                        (list
-                         (make-warning package
-                                       (G_ "should use 'cc-for-target'")
-                                       #:field 'arguments))))
+                              (evaluate-argument make-flags package))))
+                   (let ((cc (any (lambda (x)
+                                    (and (string-prefix? "CC=" x)
+                                         (substring x 3)))
+                                  make-flags/evaluated))
+                         (cxx (any (lambda (x)
+                                     (and (string-prefix? "CXX=" x)
+                                          (substring x 4)))
+                                   make-flags/evaluated)))
+                     ;; GNU's C compiler
+                     `(,@(if (and cc (string=? cc "gcc"))
+                             (list
+                              (make-warning package
+                                            (G_ "should use 'cc-for-target'")
+                                            #:field 'arguments))
+                             '())
+                       ;; GNU's C++ compiler
+                       ,@(if (and cxx (string=? cxx "g++"))
+                             (list
+                              (make-warning package
+                                            (G_ "should use 'cxx-for-target'")
+                                            #:field 'arguments))
+                             '()))))
                  '()))
            (package-arguments package))))
 
diff --git a/tests/lint.scm b/tests/lint.scm
index bda12063bc..7aa17f060a 100644
--- a/tests/lint.scm
+++ b/tests/lint.scm
@@ -40,7 +40,7 @@
   #:use-module (guix swh)
   #:use-module ((guix gexp) #:select (local-file))
   #:use-module ((guix utils) #:select (call-with-temporary-directory
-                                       cc-for-target))
+                                       cc-for-target cxx-for-target))
   #:use-module ((guix import hackage) #:select (%hackage-url))
   #:use-module ((guix import stackage) #:select (%stackage-url))
   #:use-module (gnu packages)
@@ -1117,6 +1117,14 @@
      (arguments
       `(#:make-flags (list ,(string-append "CC=" (cc-for-target))))))))
 
+(test-equal "compiler-for-target: no warnings (cxx-for-target)"
+  '()
+  (check-compiler-for-target
+   (package
+     (inherit (dummy-package "x"))
+     (arguments
+      `(#:make-flags (list ,(string-append "CXX=" (cxx-for-target))))))))
+
 (test-equal "compiler-for-target: warning (hardcoded CC=gcc)"
   "should use 'cc-for-target'"
   (single-lint-warning-message
@@ -1126,6 +1134,15 @@
       (arguments
        `(#:make-flags '("CC=gcc")))))))
 
+(test-equal "compiler-for-target: warning (hardcoded CC=g++)"
+  "should use 'cxx-for-target'"
+  (single-lint-warning-message
+   (check-compiler-for-target
+    (package
+      (inherit (dummy-package "x"))
+      (arguments
+       `(#:make-flags '("CXX=g++")))))))
+
 (test-end "lint")
 
 ;; Local Variables:
-- 
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