[shepherd] 01/01: service: Don't raise error when stopping an already stopped service.

[Ricardo Wurmus]

rekado pushed a commit to branch master
in repository shepherd.

commit 5368ee4a9f0e71a091883c0b6bddbcf33ab1ecf8
Author: Ricardo Wurmus <address@hidden>
Date:   Sun Feb 3 23:25:22 2019 +0100

    service: Don't raise error when stopping an already stopped service.
    
    * modules/shepherd/service.scm (stop): If a service by the given name exists
    and is already stopped, then don't raise an error.
    * tests/basic.sh: Add test.
---
 modules/shepherd/service.scm | 14 ++++++++++----
 tests/basic.sh               |  5 +++++
 2 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/modules/shepherd/service.scm b/modules/shepherd/service.scm
index 34a55a1..bc75eca 100644
--- a/modules/shepherd/service.scm
+++ b/modules/shepherd/service.scm
@@ -4,6 +4,7 @@
 ;; Copyright (C) 2014 Alex Sassmannshausen <address@hidden>
 ;; Copyright (C) 2016 Alex Kost <address@hidden>
 ;; Copyright (C) 2018 Carlo Zancanaro <address@hidden>
+;; Copyright (C) 2019 Ricardo Wurmus <address@hidden>
 ;;
 ;; This file is part of the GNU Shepherd.
 ;;
@@ -592,13 +593,18 @@ Used by `start' and `enforce'."
 ;; Stopping by name.
 (define-method (stop (obj <symbol>) . args)
   (let ((which (lookup-running obj)))
-    (if (not which)
-       (let ((unknown (lookup-running 'unknown)))
+    (if which
+       (apply stop which args)
+        (let ((unknown (lookup-running 'unknown)))
          (if (and unknown
                   (defines-action? unknown 'stop))
              (apply action unknown 'stop obj args)
-              (raise (condition (&missing-service-error (name obj))))))
-        (apply stop which args))))
+              ;; Only print an error if the service does not exist.
+              (match (lookup-services obj)
+                (()
+                 (raise (condition (&missing-service-error (name obj)))))
+                ((stopped . _)
+                 (list))))))))
 
 (define-method (action (obj <symbol>) the-action . args)
   "Perform THE-ACTION on all the services named OBJ.  Return the list of
diff --git a/tests/basic.sh b/tests/basic.sh
index 79caa32..27998bd 100644
--- a/tests/basic.sh
+++ b/tests/basic.sh
@@ -91,6 +91,11 @@ $herd stop test
 
 $herd status test | grep stopped
 
+# Stopping a stopped service should be a no-op.
+out=$($herd stop test)
+test $?
+test -z "$out"
+
 # Disable a service and make sure it cannot be started.
 $herd disable test-2
 if $herd start test-2