[bug#62223] [PATCH] image: Prefer gpt partition table for efi disk images

[Sergey Trofimov <sarg@sarg.org.ru>]

Hi guix, I got curious, what the easiest way to migrate existing guix os to a
new machine could be, and I've came to a conclusion that `guix system image`
fits this scenario perfectly. So I've tried to run `guix system image
--image-type=efi-raw --persistent --save-provenance system.scm`, but the
resulting image contained MBR style partition table. Although MBR support is a
must for an UEFI implementor, a better choice would be to use GPT style table.

* gnu/system/image.scm (efi-disk-image): Use gpt partition-table-type.
(efi32-disk-image): Use gpt partition-table-type.
* gnu/tests/image.scm: Assert partition table type of efi-disk-image.
---
 gnu/system/image.scm |  2 ++
 gnu/tests/image.scm  | 23 ++++++++++++++++++-----
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/gnu/system/image.scm b/gnu/system/image.scm
index afef79185f..5356ecd616 100644
--- a/gnu/system/image.scm
+++ b/gnu/system/image.scm
@@ -147,11 +147,13 @@ (define root-partition
 (define efi-disk-image
   (image-without-os
    (format 'disk-image)
+   (partition-table-type 'gpt)
    (partitions (list esp-partition root-partition))))
 
 (define efi32-disk-image
   (image-without-os
    (format 'disk-image)
+   (partition-table-type 'gpt)
    (partitions (list esp32-partition root-partition))))
 
 (define iso9660-image
diff --git a/gnu/tests/image.scm b/gnu/tests/image.scm
index 99d34b7670..be6852cae0 100644
--- a/gnu/tests/image.scm
+++ b/gnu/tests/image.scm
@@ -20,7 +20,7 @@ (define-module (gnu tests image)
   #:use-module (gnu)
   #:use-module (gnu image)
   #:use-module (gnu tests)
-  #:autoload   (gnu system image) (system-image root-offset)
+  #:autoload   (gnu system image) (system-image root-offset image-with-os efi-disk-image)
   #:use-module (gnu system uuid)
   #:use-module (gnu system vm)
   #:use-module (gnu packages guile)
@@ -153,6 +153,10 @@ (define i5
       (flags '(boot))
       (initializer dummy-initializer))))))
 
+;; A efi disk image with default partitions
+(define i6
+  (image-with-os efi-disk-image %simple-efi-os))
+
 (define (run-images-test)
   (define test
     (with-imported-modules '((srfi srfi-64)
@@ -202,10 +206,10 @@ (define d2-device
               (disk-get-primary-partition-count (disk-new d2-device)))
 
             (test-equal "test"
-                (let* ((disk (disk-new d2-device))
-                       (partitions (disk-partitions disk))
-                       (boot-partition (find normal-partition? partitions)))
-                  (partition-get-name boot-partition)))
+              (let* ((disk (disk-new d2-device))
+                     (partitions (disk-partitions disk))
+                     (boot-partition (find normal-partition? partitions)))
+                (partition-get-name boot-partition)))
 
             ;; Image i3.
             (define i3-image
@@ -259,6 +263,15 @@ (define (sector->byte sector)
                    (filter data-partition?
                            (disk-partitions (disk-new d5-device)))))
 
+            ;; Image i6.
+            (define i6-image
+              #$(system-image i6))
+            (define d6-device
+              (get-device i6-image))
+
+            (test-equal "gpt"
+              (disk-type-name (disk-probe d6-device)))
+
             (test-end)))))
 
   (gexp->derivation "images-test" test))
-- 
2.39.2