services: configuration: Step back from *unspecified*.

Fixes <https://issues.guix.gnu.org/56799>.

This partially reverts 8cb1a49a3998c39f315a4199b7d4a121a6d66449.

Rationale: *unspecified* cannot be serialized thus used as a G-Expression
input, which is problematic/inconvenient when using deeply nested records.  As
an example, jami-service-type was broken when using partially defined
<jami-account> records.

* gnu/services/configuration.scm (define-maybe-helper): Check against the
'unset symbol.
(normalize-field-type+def): Adjust value to 'unset.
(define-configuration-helper): Use 'unset as the default value thunk.
* gnu/services/file-sharing.scm (serialize-maybe-string): Check against the
'unset symbol.
(serialize-maybe-file-object): Likewise.
* gnu/services/messaging.scm (define-all-configurations): Use 'unset as
value.
(raw-content?): Check against 'unset symbol.
(prosody-configuration)[http-max-content-size]: Default to 'unset.
[http-external-url]: Likewise.
[mod-muc]: Likewise.
[raw-content]: Likewise.
* gnu/services/networking.scm (opendht-configuration): Adjust documentation.
* gnu/services/telephony.scm (jami-shepherd-services): Replace *undefined*
with the 'unset symbol.
* tests/services/configuration.scm ("maybe type, no default"): Check against
the 'unset symbol.
* doc/guix.texi: Regenerate the opendht-configuration,
openvpn-client-configuration and openvpn-server-configuration documentation.

5 files changed, 19 insertions, 20 deletions

diff --git a/gnu/services/configuration.scm b/gnu/services/configuration.scm
index e3c101d042..3007e8de35 100644
--- a/gnu/services/configuration.scm
+++ b/gnu/services/configuration.scm
@@ -3,7 +3,7 @@
 ;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
 ;;; Copyright © 2017, 2018 Clément Lassieur <clement@lassieur.org>
 ;;; Copyright © 2021 Xinglu Chen <public@yoctocell.xyz>
-;;; Copyright © 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
+;;; Copyright © 2021, 2022 Maxim Cournoyer <maxim.cournoyer@gmail.com>
 ;;; Copyright © 2021 Andrew Tropin <andrew@trop.in>
 ;;; Copyright © 2022 Maxime Devos <maximedevos@telenet.be>
 ;;;
@@ -142,8 +142,7 @@ does not have a default value" field kind)))
                                     (id #'stem #'serialize-maybe- #'stem))))
        #`(begin
            (define (maybe-stem? val)
-             (or (unspecified? val)
-                 (stem? val)))
+             (or (eq? val 'unset) (stem? val)))
            #,@(if serialize?
                   (list #'(define (serialize-maybe-stem field-name val)
                             (if (stem? val)
@@ -171,10 +170,10 @@ does not have a default value" field kind)))
      (values #'(field-type def)))
     ((field-type)
      (identifier? #'field-type)
-     (values #'(field-type *unspecified*)))
+     (values #'(field-type 'unset)))
     (field-type
      (identifier? #'field-type)
-     (values #'(field-type *unspecified*)))))
+     (values #'(field-type 'unset)))))
 
 (define (define-configuration-helper serialize? serializer-prefix syn)
   (syntax-case syn ()
@@ -262,7 +261,7 @@ does not have a default value" field kind)))
                         (lambda ()
                           (display '#,(id #'stem #'% #'stem))
                           (if (eq? (syntax->datum field-default)
-                                   '*unspecified*)
+                                   'unset)
                               (configuration-missing-default-value
                                '#,(id #'stem #'% #'stem) 'field)
                               field-default)))
diff --git a/gnu/services/file-sharing.scm b/gnu/services/file-sharing.scm
index e32d1f145d..5df8b0d597 100644
--- a/gnu/services/file-sharing.scm
+++ b/gnu/services/file-sharing.scm
@@ -115,7 +115,7 @@ type generated and used by Transmission clients, suitable for passing to the
 (set! serialize-maybe-string
   (lambda (field-name val)
     (serialize-string field-name
-                      (if (unspecified? val)
+                      (if (eq? val 'unset)
                           ""
                           val))))
 
@@ -180,7 +180,7 @@ type generated and used by Transmission clients, suitable for passing to the
 (define-maybe file-object)
 (set! serialize-maybe-file-object
   (lambda (field-name val)
-    (if (unspecified? val)
+    (if (eq? val 'unset)
         (serialize-string field-name "")
         (serialize-file-object field-name val))))
 
diff --git a/gnu/services/messaging.scm b/gnu/services/messaging.scm
index 651f90adb2..00a1c80a14 100644
--- a/gnu/services/messaging.scm
+++ b/gnu/services/messaging.scm
@@ -90,7 +90,7 @@
                      ((new-def ...)
                       (map (lambda (def target)
                              (if (eq? 'common (syntax->datum target))
-                                 #'*unspecified* def))
+                                 #''unset def))
                            #'(def ...) #'(target ...)))
                      ((new-doc ...)
                       (map (lambda (doc target)
@@ -200,7 +200,7 @@
 (define-maybe file-object-list)
 
 (define (raw-content? val)
-  (not (unspecified? val)))
+  (not (eq? val 'unset)))
 (define (serialize-raw-content field-name val)
   val)
 (define-maybe raw-content)
@@ -474,12 +474,12 @@ by the Prosody service.  See @url{https://prosody.im/doc/logging}."
      global)
 
     (http-max-content-size
-     (maybe-non-negative-integer *unspecified*)
+     (maybe-non-negative-integer 'unset)
      "Maximum allowed size of the HTTP body (in bytes)."
      common)
 
     (http-external-url
-     (maybe-string *unspecified*)
+     (maybe-string 'unset)
      "Some modules expose their own URL in various ways.  This URL is built
 from the protocol, host and port used.  If Prosody sits behind a proxy, the
 public URL will be @code{http-external-url} instead.  See
@@ -556,7 +556,7 @@ support.  To add an external component, you simply fill the hostname field.  See
      int-component)
 
     (mod-muc
-     (maybe-mod-muc-configuration *unspecified*)
+     (maybe-mod-muc-configuration 'unset)
      "Multi-user chat (MUC) is Prosody's module for allowing you to create
 hosted chatrooms/conferences for XMPP users.
 
@@ -573,7 +573,7 @@ See also @url{https://prosody.im/doc/modules/mod_muc}."
      ext-component)
 
     (raw-content
-     (maybe-raw-content *unspecified*)
+     (maybe-raw-content 'unset)
      "Raw content that will be added to the configuration file."
      common)))
 
diff --git a/gnu/services/networking.scm b/gnu/services/networking.scm
index 3ddcdcc251..3c6395b6ca 100644
--- a/gnu/services/networking.scm
+++ b/gnu/services/networking.scm
@@ -772,11 +772,11 @@ logging is disabled.")
 network.  A specific port value can be provided by appending the @code{:PORT}
 suffix.  By default, it uses the Jami bootstrap nodes, but any host can be
 specified here.  It's also possible to disable bootstrapping by explicitly
-setting this field to the @code{*unspecified*} value.")
+setting this field to the @code{'unset} value.")
   (port
    (maybe-number 4222)
-   "The UDP port to bind to.  When set to @code{*unspecified*}, an available
-port is automatically selected.")
+   "The UDP port to bind to.  When left unspecified, an available port is
+automatically selected.")
   (proxy-server-port
    maybe-number
    "Spawn a proxy server listening on the specified port.")
diff --git a/gnu/services/telephony.scm b/gnu/services/telephony.scm
index e8bfbc88c5..7152f3b38d 100644
--- a/gnu/services/telephony.scm
+++ b/gnu/services/telephony.scm
@@ -307,7 +307,7 @@ CONFIG, a <jami-configuration> object."
          (dbus (jami-configuration-dbus config))
          (dbus-daemon (file-append dbus "/bin/dbus-daemon"))
          (accounts (jami-configuration-accounts config))
-         (declarative-mode? (not (unspecified? accounts))))
+         (declarative-mode? (not (eq? 'unset accounts))))
 
     (with-extensions (list guile-packrat ;used by guile-ac-d-bus
                            guile-ac-d-bus
@@ -649,7 +649,7 @@ argument, either a registered username or the fingerprint of the account.")
                                           account-details)
                            (let ((username (archive-name->username
                                             archive)))
-                             (when (not (unspecified? allowed-contacts))
+                             (when (not (eq? 'unset allowed-contacts))
                                ;; Reject calls from unknown contacts.
                                (set-account-details
                                 '(("DHT.PublicInCalls" . "false")) username)
@@ -659,7 +659,7 @@ argument, either a registered username or the fingerprint of the account.")
                                ;; Add allowed ones.
                                (for-each (cut add-contact <> username)
                                          allowed-contacts))
-                             (when (not (unspecified? moderators))
+                             (when (not (eq? 'unset moderators))
                                ;; Disable the 'AllModerators' property.
                                (set-all-moderators #f username)
                                ;; Remove all moderators.