gnu: services: Revert to deleting and updating all matching services

This patch reverts the behavior introduced in
181951207339508789b28ba7cb914f983319920f which caused ‘modify-services’
clauses to only match a single instance of a service.

We will now match all service instances when doing a deletion or update, while
still raising an exception when trying to match against a service that does
not exist in the services list, or which was deleted explicitly by a ‘delete’
clause (or an update clause that returns ‘#f’ for the service).

Fixes: #64106

* gnu/services.scm (%modify-services): New procedure.
(modify-services): Use it.
(apply-clauses): Add DELETED-SERVICES argument, change to modify one service
at a time.
* tests/services.scm
("modify-services: delete then modify")
("modify-services: modify then delete")
("modify-services: delete multiple services of the same type")
("modify-services: modify multiple services of the same type"): New tests.

Signed-off-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Modified-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>

1 files changed, 68 insertions, 0 deletions

diff --git a/tests/services.scm b/tests/services.scm
index 20ff4d317e..98b584f6c0 100644
--- a/tests/services.scm
+++ b/tests/services.scm
@@ -370,4 +370,72 @@
          (modify-services services
            (t2 value => 22)))))
 
+(test-error "modify-services: delete then modify"
+  #t
+  (let* ((t1 (service-type (name 't1)
+                           (extensions '())
+                           (description "")))
+         (t2 (service-type (name 't2)
+                           (extensions '())
+                           (description "")))
+         (t3 (service-type (name 't3)
+                           (extensions '())
+                           (description "")))
+         (services (list (service t1 1) (service t2 2) (service t3 3))))
+    (map service-value
+         (modify-services services
+           (delete t2)
+           (t2 value => 22)))))
+
+(test-equal "modify-services: modify then delete"
+  '(2 3)
+  (let* ((t1 (service-type (name 't1)
+                           (extensions '())
+                           (description "")))
+         (t2 (service-type (name 't2)
+                           (extensions '())
+                           (description "")))
+         (t3 (service-type (name 't3)
+                           (extensions '())
+                           (description "")))
+         (services (list (service t1 1) (service t2 2) (service t3 3))))
+    (map service-value
+         (modify-services services
+           (t1 value => 11)
+           (delete t1)))))
+
+(test-equal "modify-services: delete multiple services of the same type"
+  '(1 3)
+  (let* ((t1 (service-type (name 't1)
+                           (extensions '())
+                           (description "")))
+         (t2 (service-type (name 't2)
+                           (extensions '())
+                           (description "")))
+         (t3 (service-type (name 't3)
+                           (extensions '())
+                           (description "")))
+         (services (list (service t1 1) (service t2 2)
+                         (service t2 2) (service t3 3))))
+    (map service-value
+         (modify-services services
+           (delete t2)))))
+
+(test-equal "modify-services: modify multiple services of the same type"
+  '(1 12 13 4)
+  (let* ((t1 (service-type (name 't1)
+                           (extensions '())
+                           (description "")))
+         (t2 (service-type (name 't2)
+                           (extensions '())
+                           (description "")))
+         (t3 (service-type (name 't3)
+                           (extensions '())
+                           (description "")))
+         (services (list (service t1 1) (service t2 2)
+                         (service t2 3) (service t3 4))))
+    (map service-value
+         (modify-services services
+           (t2 value => (+ value 10))))))
+
 (test-end)