[shepherd] 02/03: service: Remove support for the 'unknown' service.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository shepherd.

commit 2afe1feeee4f2b23e9fa70bb8462b59d37f34f72
Author: Ludovic Courtès <ludo@gnu.org>
AuthorDate: Sat Feb 25 23:16:24 2023 +0100

    service: Remove support for the 'unknown' service.
    
    This feature was untested and there were no clear use cases.
    
    * modules/shepherd/service.scm (launch-service, stop, action): Remove
    lookup of the 'unknown' service.
    (handle-unknown): Remove.
    * doc/shepherd.texi (The root and unknown services): Rename to...
    (The root Service): ... this.  Remove paragraph about the 'unknown'
    service.
---
 doc/shepherd.texi            | 18 +++-----------
 modules/shepherd/service.scm | 58 ++++++--------------------------------------
 2 files changed, 12 insertions(+), 64 deletions(-)

diff --git a/doc/shepherd.texi b/doc/shepherd.texi
index b4275e6..2224ee0 100644
--- a/doc/shepherd.texi
+++ b/doc/shepherd.texi
@@ -499,7 +499,7 @@ It causes the @var{action} of the @var{service} to be 
invoked.  When
 @code{detailed-status}, the @code{root} service is used@footnote{This
 shorthand does not work for other actions such as @code{stop}, because
 inadvertently typing @code{herd stop} would stop all the services, which
-could be pretty annoying.} (@pxref{The root and unknown services}, for
+could be pretty annoying.} (@pxref{The root Service}, for
 more information on the @code{root} service.)
 
 For each action, you should pass the appropriate @var{arg}s.  Actions
@@ -606,7 +606,7 @@ defined in the @code{(shepherd service)} module.
                                    stopping services.
 * Service Examples::             Examples that show how services are used.
 * Managing User Services::       Running the Shepherd as a user.
-* The root and unknown services:: Special services in the Shepherd.
+* The root Service::             The service that comes first.
 @end menu
 
 @c @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@@ -1369,8 +1369,8 @@ Then, individual user services can be put in
 
 @c @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 
-@node The root and unknown services
-@section The @code{root} and @code{unknown} services
+@node The root Service
+@section The @code{root} Service
 
 @cindex root service
 @cindex special services
@@ -1425,16 +1425,6 @@ respawnable services are started, as otherwise we would 
not get the
 
 @end table
 
-@cindex unknown service
-@cindex fallback service
-The @code{unknown} service must be defined by the user and if it
-exists, is used as a fallback whenever we try to invoke an unknown
-action of an existing service or use a service that does not exist.
-This is useful only in few cases, but enables you to do various sorts
-of unusual things.
-
-@c FIXME-CRITICAL: finish
-
 @c @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
 
 @node Misc Facilities
diff --git a/modules/shepherd/service.scm b/modules/shepherd/service.scm
index 4a4824a..2c171d0 100644
--- a/modules/shepherd/service.scm
+++ b/modules/shepherd/service.scm
@@ -87,7 +87,6 @@
             register-services
             provided-by
             required-by
-            handle-unknown
 
             default-service-termination-handler
             default-environment-variables
@@ -990,14 +989,7 @@ Used by `start' and `enforce'."
          ;; None running yet, start one.
          (find (lambda (service)
                  (apply proc service args))
-               possibilities)
-
-         ;; Failed to start something, try the 'unknown' service.
-         (let ((unknown (lookup-running 'unknown)))
-           (if (and unknown
-                    (defines-action? unknown 'start))
-               (apply action unknown 'start name args)
-               #f))))))
+               possibilities)))))
 
 ;; Starting by name.
 (define-method (start (obj <symbol>) . args)
@@ -1012,27 +1004,19 @@ Used by `start' and `enforce'."
   (let ((which (find (negate stopped?) (lookup-services obj))))
     (if which
        (apply stop which args)
-        (let ((unknown (lookup-running 'unknown)))
-         (if (and unknown
-                  (defines-action? unknown 'stop))
-             (apply action unknown 'stop obj args)
-              ;; Only print an error if the service does not exist.
-              (match (lookup-services obj)
-                (()
-                 (raise (condition (&missing-service-error (name obj)))))
-                ((stopped . _)
-                 (list))))))))
+        ;; 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
 results."
   (let ((which-services (lookup-running-or-providing obj)))
     (if (null? which-services)
-       (let ((unknown (lookup-running 'unknown)))
-         (if (and unknown
-                  (defines-action? unknown 'action))
-             (apply action unknown 'action the-action args)
-              (raise (condition (&missing-service-error (name obj))))))
+        (raise (condition (&missing-service-error (name obj))))
         (map (lambda (service)
                (apply action service the-action args))
              which-services))))
@@ -1067,32 +1051,6 @@ background:~{ ~a~}."
 
 
 
-;; Handling of unprovided service-symbols.  This can be called in
-;; either of the following ways (i.e. with either three or four
-;; arguments):
-;;   handle-unknown SERVICE-SYMBOL [ 'start | 'stop ] ARGS
-;;   handle-unknown SERVICE-SYMBOL 'action THE_ACTION ARGS
-(define (handle-unknown . args)
-  (let ((unknown (lookup-running 'unknown)))
-    ;; FIXME: Display message if no unknown service.
-    (when unknown
-      (apply (case-lambda
-              ;; Start or stop.
-              ((service-symbol start/stop args)
-               (if (defines-action? unknown start/stop)
-                   (apply action unknown start/stop service-symbol args)
-                   ;; FIXME: Bad message.
-                   (local-output "Cannot ~a ~a." start/stop service-symbol)))
-              ;; Action.
-              ((service-symbol action-sym the-action args)
-               (assert (eq? action-sym 'action))
-               (if (defines-action? unknown 'action)
-                   (apply action unknown 'action service-symbol
-                           the-action args)
-                   (local-output (l10n "No service provides ~a.")
-                                  service-symbol))))
-             args))))
-
 ;; Check if any of SERVICES is running.  If this is the case, return
 ;; it.  If none, return `#f'.  Only the first one found will be
 ;; returned; this is because this is mainly intended to be applied on