[bug#67503] [PATCH 2/2] guix: import: Report go version for go importer.

[Efraim Flashner <efraim@flashner.co.il>]

* guix/import/go.scm (go-package, go.mod-go-version): New procedures.
(go-module->guix-package): Add the #:go keyword in the generated package
definition if the required go is newer than the default go.

Change-Id: I8d005740a442330ac307a40a53764c803ceffc4f
---
 guix/import/go.scm | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/guix/import/go.scm b/guix/import/go.scm
index 940cdac4b0..dd9298808d 100644
--- a/guix/import/go.scm
+++ b/guix/import/go.scm
@@ -29,6 +29,7 @@ (define-module (guix import go)
   #:use-module (guix git)
   #:use-module (guix hash)
   #:use-module (guix i18n)
+  #:use-module ((guix utils) #:select (version>?))
   #:use-module (guix diagnostics)
   #:use-module (guix import utils)
   #:use-module (guix import json)
@@ -93,6 +94,11 @@ (define-module (guix import go)
 
 ;;; Code:
 
+(define (go-package)
+  "Return the 'go' package.  This is a lazy reference so that we don't
+depend on (gnu packages golang)."
+  (module-ref (resolve-interface '(gnu packages golang)) 'go))
+
 (define http-fetch*
   ;; Like http-fetch, but memoized and returning the body as a string.
   (memoize (lambda args
@@ -314,7 +320,7 @@ (define (parse-go.mod content)
   (define-peg-pattern with all (or (and module-path version) file-path))
   (define-peg-pattern replace all (and original => with EOL))
   (define-peg-pattern replace-top body
-    (and (ignore "replace") 
+    (and (ignore "replace")
          (or (and block-start (* (or replace block-line)) block-end) replace)))
 
   ;; RetractSpec = ( Version | "[" Version "," Version "]" ) newline .
@@ -378,6 +384,17 @@ (define (go.mod-requirements go.mod)
 ;; Prevent inlining of this procedure, which is accessed by unit tests.
 (set! go.mod-requirements go.mod-requirements)
 
+(define (go.mod-go-version go.mod)
+  "Return the minimum version of go required to specified by GO.MOD."
+  (let ((go-version (go.mod-directives go.mod 'go)))
+    (if (null? go-version)
+      ;; If the go directive is missing, go 1.16 is assumed.
+      '(version "1.16")
+      (flatten go-version))))
+
+;; Prevent inlining of this procedure, which is accessed by unit tests.
+(set! go.mod-go-version go.mod-go-version)
+
 (define-record-type <vcs>
   (%make-vcs url-prefix root-regex type)
   vcs?
@@ -610,6 +627,7 @@ (define* (go-module->guix-package module-path #:key
                     available-versions
                     module-path))
          (content (fetch-go.mod goproxy module-path version*))
+         (min-go-version (second (go.mod-go-version (parse-go.mod content))))
          (dependencies+versions (go.mod-requirements (parse-go.mod content)))
          (dependencies (if pin-versions?
                            dependencies+versions
@@ -634,10 +652,13 @@ (define* (go-module->guix-package module-path #:key
          ,(vcs->origin vcs-type vcs-repo-url version*))
         (build-system go-build-system)
         (arguments
-         '(#:import-path ,module-path
-           ,@(if (string=? module-path-sans-suffix root-module-path)
-                 '()
-                 `(#:unpack-path ,root-module-path))))
+         (list ,@(if (version>? min-go-version (package-version (go-package)))
+                     `(#:go ,(string->number min-go-version))
+                     '())
+               #:import-path ,module-path
+               ,@(if (string=? module-path-sans-suffix root-module-path)
+                     '()
+                     `(#:unpack-path ,root-module-path))))
         ,@(maybe-propagated-inputs
            (map (match-lambda
                   ((name version)
-- 
Efraim Flashner   <efraim@flashner.co.il>   רנשלפ םירפא
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