[shepherd] 03/03: service: Do not attempt to restart transient services.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository shepherd.

commit 8ae2780ca22f63d10e0e7e3fa75c5e864e0fad1a
Author: Ludovic Courtès <ludo@gnu.org>
AuthorDate: Fri May 26 15:07:09 2023 +0200

    service: Do not attempt to restart transient services.
    
    * modules/shepherd/service.scm (perform-service-action): In 'restart',
    do not restart transient services.
    * tests/transient.sh: Test it.
    * NEWS: Update.
---
 NEWS                         | 6 ++++++
 modules/shepherd/service.scm | 3 ++-
 tests/transient.sh           | 8 ++++++++
 3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index 516244a..54df05c 100644
--- a/NEWS
+++ b/NEWS
@@ -30,6 +30,12 @@ service (typically failing to start) while the original 
service would still be
 running “in the shadows” (responding to SIGCHLD or to incoming connections,
 and so on).
 
+** ‘herd restart SERVICE’ does not restart transient services
+
+In 0.10.0, ‘herd restart’ could end up attempt to restart transient services,
+which is bound to fail and could even lead to a deadlock since the service has
+been terminated.
+
 * Changes in 0.10.0
 
 ** Distinguish ‘starting’ and ‘stopping’ intermediate service statuses
diff --git a/modules/shepherd/service.scm b/modules/shepherd/service.scm
index f8849d5..63e7155 100644
--- a/modules/shepherd/service.scm
+++ b/modules/shepherd/service.scm
@@ -941,7 +941,8 @@ the action."
       ((restart)
        (lambda (running . args)
          (let ((stopped-services (stop-service service)))
-           (for-each start-service stopped-services)
+           (for-each start-service
+                     (remove transient-service? stopped-services))
            #t)))
       ((status)
        ;; Return the service itself.  It is automatically converted to an sexp
diff --git a/tests/transient.sh b/tests/transient.sh
index f61bb46..3f70dac 100644
--- a/tests/transient.sh
+++ b/tests/transient.sh
@@ -63,3 +63,11 @@ kill $($herd status transient-test2 | grep Running | sed 
-e's/^.* \([0-9]\+\).*$
 $herd status transient-test2 && false
 
 test $($herd status | grep transient-test | wc -l) -eq 0
+
+# Ensure that restarting a transient service is impossible.
+$herd load root "$conf"
+$herd start transient-test1
+$herd restart transient-test1
+$herd status transient-test1 && false
+
+$herd unload root transient-test2