bug#33266: guix-copy: Honor the SSH port of a host when defined in ~/.ssh/config

[Maxim Cournoyer <maxim.cournoyer@gmail.com>]

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Hello,

I recently stumbled on the bug where guix copy would the port 22 even
when I had specified a different one in my ~/.ssh/config file.

This bug is triggered when omitting the port in the --to= (or --from)
expression, such as in

guix copy --to=somehost bash

And where somehost exists in ~/.ssh/config, say:

Host somehost
     User someuser
     HostName someplace.somedns.net
     Port 1234

Instead of using port 1234, the port 22 would be used.  Commit
cc1dfc202f is the reason of this overriding; the attached patch 
reverts it, with a detailed explanation.

Thank you,

Maxim


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From 942eb8cabef5b7c8b4425c765b6ee2ac9f529ad8 Mon Sep 17 00:00:00 2001
From: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Date: Sun, 4 Nov 2018 23:35:16 -0500
Subject: [PATCH] Revert "copy: Default to port 22."

This reverts commit cc1dfc202f2fefb6c2eb9467d1fc90a9154550c9.  Specifying a
default port had the undesirable effect of disregarding a port specification
for a given host in the ~/.ssh/config that would otherwise have been honored
at the time `open-ssh-session' calls the `session-parse-config!' method.

In any case, `make-session' will default the port value of the created session
to 22 if left unspecified.
---
 guix/scripts/copy.scm | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/guix/scripts/copy.scm b/guix/scripts/copy.scm
index 4c8592985..d35eed74e 100644
--- a/guix/scripts/copy.scm
+++ b/guix/scripts/copy.scm
@@ -75,8 +75,7 @@ package names, build the underlying packages before sending them."
 
       (and (or (assoc-ref opts 'dry-run?)
                (build-derivations local drv))
-           (let* ((session (open-ssh-session host #:user user
-                                             #:port (or port 22)))
+           (let* ((session (open-ssh-session host #:user user #:port port))
                   (sent    (send-files local items
                                        (connect-to-remote-daemon session)
                                        #:recursive? #t)))
@@ -89,7 +88,7 @@ package names, build the underlying packages before sending them."
     (let*-values (((user host port)
                    (ssh-spec->user+host+port source))
                   ((session)
-                   (open-ssh-session host #:user user #:port (or port 22)))
+                   (open-ssh-session host #:user user #:port port))
                   ((remote)
                    (connect-to-remote-daemon session)))
       (set-build-options-from-command-line local opts)
-- 
2.19.0