download: Honor ‘GUIX_DOWNLOAD_METHODS’ environment variable.

This replaces ‘GUIX_DOWNLOAD_FALLBACK_TEST’ and allows you to test
various download methods, like so:

  GUIX_DOWNLOAD_METHODS=nar guix build guile-gcrypt -S --check
  GUIX_DOWNLOAD_METHODS=disarchive guix build hello -S --check

* guix/build/download.scm (%download-methods): New variable.
(download-method-enabled?): New procedure.
(url-fetch): Define ‘initial-uris’; honor ‘download-method-enabled?’.
Call ‘disarchive-fetch/any’ only when the 'disarchive method is enabled.
* guix/build/git.scm (git-fetch-with-fallback): Honor
‘download-method-enabled?’.
* guix/download.scm (%download-methods): New variable.
(%download-fallback-test): Remove.
(built-in-download): Add #:download-methods parameter and honor it.
(url-fetch*): Pass #:content-addressed-mirrors and #:disarchive-mirrors
unconditionally.
* guix/git-download.scm (git-fetch/in-band*): Pass “git url”
unconditionally.
(git-fetch/built-in): Likewise.  Pass “download-methods”.
* guix/bzr-download.scm (bzr-fetch)[build]: Honor ‘download-method-enabled?’.
Pass ‘GUIX_DOWNLOAD_METHODS’ to #:env-vars.
* guix/cvs-download.scm (cvs-fetch)[build]: Honor ‘download-method-enabled?’.
Pass ‘GUIX_DOWNLOAD_METHODS’ to #:env-vars.
* guix/hg-download.scm (hg-fetch): Honor ‘download-method-enabled?’.
Pass #:env-vars to ‘gexp->derivation’.
* guix/scripts/perform-download.scm (perform-download): Honor
“download-methods” from DRV.  Parameterize ‘%download-methods’ before
calling ‘url-fetch’.
(perform-git-download): Likewise.
* guix/svn-download.scm (svn-fetch): Honor ‘download-method-enabled?’.
Pass ‘GUIX_DOWNLOAD_METHODS’ to #:env-vars.
(svn-multi-fetch): Likewise.

Change-Id: Ia3402e17f0303dfa964bdc761265efe8a1dd69ab

1 files changed, 17 insertions, 7 deletions

diff --git a/guix/cvs-download.scm b/guix/cvs-download.scm
index c0c526b9db..023054941b 100644
--- a/guix/cvs-download.scm
+++ b/guix/cvs-download.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2014, 2015, 2016, 2017, 2019 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2014-2017, 2019, 2024 Ludovic Courtès <ludo@gnu.org>
 ;;; Copyright © 2014 Sree Harsha Totakura <sreeharsha@totakura.in>
 ;;; Copyright © 2015 Mark H Weaver <mhw@netris.org>
 ;;;
@@ -73,6 +73,7 @@ HASH-ALGO (a symbol).  Use NAME as the file name, or a generic name if #f."
   (define modules
     (delete '(guix config)
             (source-module-closure '((guix build cvs)
+                                     (guix build download)
                                      (guix build download-nar)))))
   (define build
     (with-imported-modules modules
@@ -80,20 +81,29 @@ HASH-ALGO (a symbol).  Use NAME as the file name, or a generic name if #f."
                              guile-lzlib)
         #~(begin
             (use-modules (guix build cvs)
+                         ((guix build download)
+                          #:select (download-method-enabled?))
                          (guix build download-nar))
 
-            (or (cvs-fetch '#$(cvs-reference-root-directory ref)
-                           '#$(cvs-reference-module ref)
-                           '#$(cvs-reference-revision ref)
-                           #$output
-                           #:cvs-command (string-append #+cvs "/bin/cvs"))
-                (download-nar #$output))))))
+            (or (and (download-method-enabled? 'upstream)
+                     (cvs-fetch '#$(cvs-reference-root-directory ref)
+                                '#$(cvs-reference-module ref)
+                                '#$(cvs-reference-revision ref)
+                                #$output
+                                #:cvs-command
+                                #+(file-append cvs "/bin/cvs")))
+                (and (download-method-enabled? 'nar)
+                     (download-nar #$output)))))))
 
   (mlet %store-monad ((guile (package->derivation guile system)))
     (gexp->derivation (or name "cvs-checkout") build
                       #:leaked-env-vars '("http_proxy" "https_proxy"
                                           "LC_ALL" "LC_MESSAGES" "LANG"
                                           "COLUMNS")
+                      #:env-vars (match (getenv "GUIX_DOWNLOAD_METHODS")
+                                   (#f '())
+                                   (value
+                                    `(("GUIX_DOWNLOAD_METHODS" . ,value))))
                       #:system system
                       #:hash-algo hash-algo
                       #:hash hash