bug#38320: Cuirass: Allow to use authenticated Git repositories as inputs

[Mathieu Othacehe]

Hey Ludo,

Thanks for reviewing :)

> It LGTM, and I like that it’s actually a small patch.
>
> Until now, we had conditionals like the ‘module-defined?’ thing above to
> allow for a smooth transition from older Guile-Git versions.  Do we want
> to keep doing that?
>
> If we do, then perhaps you should arrange so that uses of the new
> Guile-Git APIs that appeared in 0.3.0 are conditional.
>
> I’d say we should do it if it’s easy to do and not too intrusive.
> Otherwise, let’s just require 0.3.0 and be done with it.  (‘guix pull’
> gets 0.3.0 anyway.)

Here's a version with optional authentication support. I do not find it
too intrusive, but let me know what you think!

Thanks,

Mathieu

>From 4554baf59564eb0c31cfe235acd078d54afef6d7 Mon Sep 17 00:00:00 2001
From: Mathieu Othacehe <address@hidden>
Date: Mon, 3 Feb 2020 18:05:02 +0100
Subject: [PATCH] git: Add ssh authentication support.

SSH agent authentication method is used.

* guix/git.scm (auth-method): New variable,
(clone*): pass previous variable in clone options,
(update-cached-checkout): pass previous variable in fetch options.
---
 guix/git.scm | 21 ++++++++++++++++++---
 1 file changed, 18 insertions(+), 3 deletions(-)

diff --git a/guix/git.scm b/guix/git.scm
index a12f1eec8e..2165e612f1 100644
--- a/guix/git.scm
+++ b/guix/git.scm
@@ -1,5 +1,5 @@
 ;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2017 Mathieu Othacehe <address@hidden>
+;;; Copyright © 2017, 2020 Mathieu Othacehe <address@hidden>
 ;;; Copyright © 2018, 2019, 2020 Ludovic Courtès <address@hidden>
 ;;;
 ;;; This file is part of GNU Guix.
@@ -108,6 +108,14 @@ the 'SSL_CERT_FILE' and 'SSL_CERT_DIR' environment 
variables."
                               (string-append "R:" url)
                               url))))))
 
+;; Authentication appeared in Guile-Git 0.3.0, check if it is available.
+(define auth-supported?
+  (false-if-exception (resolve-interface '(git auth))))
+
+;; Default authentication method.
+(define auth-method (and auth-supported?
+                         (%make-auth-ssh-agent)))
+
 (define (clone* url directory)
   "Clone git repository at URL into DIRECTORY.  Upon failure,
 make sure no empty directory is left behind."
@@ -119,7 +127,11 @@ make sure no empty directory is left behind."
       ;; value in Guile-Git: <https://bugs.gnu.org/29238>.
       (if (module-defined? (resolve-interface '(git))
                            'clone-init-options)
-          (clone url directory (clone-init-options))
+          (clone url directory
+                 (if auth-supported?
+                     (make-clone-options
+                      #:fetch-options (make-fetch-options auth-method))
+                     (clone-init-options)))
           (clone url directory)))
     (lambda _
       (false-if-exception (rmdir directory)))))
@@ -281,7 +293,10 @@ When RECURSIVE? is true, check out submodules as well, if 
any."
      ;; Only fetch remote if it has not been cloned just before.
      (when (and cache-exists?
                 (not (reference-available? repository ref)))
-       (remote-fetch (remote-lookup repository "origin")))
+       (if auth-supported?
+           (remote-fetch (remote-lookup repository "origin")
+                         #:fetch-options (make-fetch-options auth-method))
+           (remote-fetch (remote-lookup repository "origin"))))
      (when recursive?
        (update-submodules repository #:log-port log-port))
      (let ((oid (switch-to-ref repository canonical-ref)))
-- 
2.25.0