bug#56799: [PATCH] services: configuration: Step back from *unspecified*.

[Maxim Cournoyer]

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
'unspecified symbol.
(normalize-field-type+def): Adjust value to 'unspecified.
(define-configuration-helper): Use 'unspecified as the default value thunk.
* gnu/services/file-sharing.scm (serialize-maybe-string): Check against the
'unspecified symbol.
(serialize-maybe-file-object): Likewise.
* gnu/services/messaging.scm (define-all-configurations): Use 'unspecified as
value.
(raw-content?): Check against 'unspecified symbol.
(prosody-configuration)[http-max-content-size]: Default to 'unspecified.
[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 'unspecified symbol.
* tests/services/configuration.scm ("maybe type, no default"): Check against
the 'unspecified symbol.
* doc/guix.texi: Regenerate the opendht-configuration,
openvpn-client-configuration and openvpn-server-configuration documentation.
---
 doc/guix.texi                    | 367 +++++++------------------------
 gnu/services/configuration.scm   |  11 +-
 gnu/services/file-sharing.scm    |   4 +-
 gnu/services/messaging.scm       |  12 +-
 gnu/services/networking.scm      |   6 +-
 gnu/services/telephony.scm       |   6 +-
 tests/services/configuration.scm |   6 +-
 7 files changed, 102 insertions(+), 310 deletions(-)

diff --git a/doc/guix.texi b/doc/guix.texi
index 12ecc1b952..a2ccf913da 100644
--- a/doc/guix.texi
+++ b/doc/guix.texi
@@ -19767,75 +19767,46 @@ The value of this service is a 
@code{opendht-configuration} object, as
 described below.
 @end defvr
 
-@deftp {Data Type} opendht-configuration
-This is the data type for the OpenDHT service configuration.
-
 @c The fields documentation has been auto-generated using the
 @c configuration->documentation procedure from
 @c (gnu services configuration).
+@deftp {Data Type} opendht-configuration
 Available @code{opendht-configuration} fields are:
 
-@deftypevr {@code{opendht-configuration} parameter} package opendht
+@table @asis
+@item @code{opendht} (default: @code{opendht}) (type: file-like)
 The @code{opendht} package to use.
 
-@end deftypevr
-
-@deftypevr {@code{opendht-configuration} parameter} boolean peer-discovery?
+@item @code{peer-discovery?} (default: @code{#f}) (type: boolean)
 Whether to enable the multicast local peer discovery mechanism.
 
-Defaults to @samp{#f}.
-
-@end deftypevr
-
-@deftypevr {@code{opendht-configuration} parameter} boolean enable-logging?
+@item @code{enable-logging?} (default: @code{#f}) (type: boolean)
 Whether to enable logging messages to syslog.  It is disabled by default
 as it is rather verbose.
 
-Defaults to @samp{#f}.
-
-@end deftypevr
-
-@deftypevr {@code{opendht-configuration} parameter} boolean debug?
+@item @code{debug?} (default: @code{#f}) (type: boolean)
 Whether to enable debug-level logging messages.  This has no effect if
 logging is disabled.
 
-Defaults to @samp{#f}.
-
-@end deftypevr
-
-@deftypevr {@code{opendht-configuration} parameter} maybe-string bootstrap-host
+@item @code{bootstrap-host} (default: @code{"bootstrap.jami.net:4222"}) (type: 
maybe-string)
 The node host name that is used to make the first connection to the
 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
-bootsrapping by explicitly setting this to the @code{*unspecified*}
-value.
+bootstrapping by explicitly setting this field to the
+@code{'unspecified} value.
 
-Defaults to @samp{"bootstrap.jami.net:4222"}.
-
-@end deftypevr
-
-@deftypevr {@code{opendht-configuration} parameter} maybe-number port
-The UDP port to bind to.  When explicitly set to @code{*unspecified*},
-an available port is automatically selected.
-
-Defaults to @samp{4222}.
-
-@end deftypevr
+@item @code{port} (default: @code{4222}) (type: maybe-number)
+The UDP port to bind to.  When left unspecified, an available port is
+automatically selected.
 
-@deftypevr {@code{opendht-configuration} parameter} maybe-number 
proxy-server-port
+@item @code{proxy-server-port} (type: maybe-number)
 Spawn a proxy server listening on the specified port.
 
-Defaults to @samp{disabled}.
-
-@end deftypevr
-
-@deftypevr {@code{opendht-configuration} parameter} maybe-number 
proxy-server-port-tls
+@item @code{proxy-server-port-tls} (type: maybe-number)
 Spawn a proxy server listening to TLS connections on the specified port.
 
-Defaults to @samp{disabled}.
-
-@end deftypevr
+@end table
 @end deftp
 
 @cindex Tor
@@ -30525,362 +30496,184 @@ Both can be run simultaneously.
 
 @c %automatically generated documentation
 
+@deftp {Data Type} openvpn-client-configuration
 Available @code{openvpn-client-configuration} fields are:
 
-@deftypevr {@code{openvpn-client-configuration} parameter} package openvpn
+@table @asis
+@item @code{openvpn} (default: @code{openvpn}) (type: file-like)
 The OpenVPN package.
 
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} string pid-file
+@item @code{pid-file} (default: @code{"/var/run/openvpn/openvpn.pid"}) (type: 
string)
 The OpenVPN pid file.
 
-Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} proto proto
+@item @code{proto} (default: @code{udp}) (type: proto)
 The protocol (UDP or TCP) used to open a channel between clients and
 servers.
 
-Defaults to @samp{udp}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} dev dev
+@item @code{dev} (default: @code{tun}) (type: dev)
 The device type used to represent the VPN connection.
 
-Defaults to @samp{tun}.
-
-@end deftypevr
-
-If you do not have some of these files (eg.@: you use a username and
-password), you can disable any of the following three fields by setting
-it to @code{*unspecified*}.
-
-@deftypevr {@code{openvpn-client-configuration} parameter} maybe-string ca
+@item @code{ca} (default: @code{"/etc/openvpn/ca.crt"}) (type: maybe-string)
 The certificate authority to check connections against.
 
-Defaults to @samp{"/etc/openvpn/ca.crt"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} maybe-string cert
+@item @code{cert} (default: @code{"/etc/openvpn/client.crt"}) (type: 
maybe-string)
 The certificate of the machine the daemon is running on.  It should be
 signed by the authority given in @code{ca}.
 
-Defaults to @samp{"/etc/openvpn/client.crt"}.
+@item @code{key} (default: @code{"/etc/openvpn/client.key"}) (type: 
maybe-string)
+The key of the machine the daemon is running on.  It must be the key
+whose certificate is @code{cert}.
 
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} maybe-string key
-The key of the machine the daemon is running on.  It must be the key whose
-certificate is @code{cert}.
-
-Defaults to @samp{"/etc/openvpn/client.key"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} boolean comp-lzo?
+@item @code{comp-lzo?} (default: @code{#t}) (type: boolean)
 Whether to use the lzo compression algorithm.
 
-Defaults to @samp{#t}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-key?
+@item @code{persist-key?} (default: @code{#t}) (type: boolean)
 Don't re-read key files across SIGUSR1 or --ping-restart.
 
-Defaults to @samp{#t}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} boolean persist-tun?
+@item @code{persist-tun?} (default: @code{#t}) (type: boolean)
 Don't close and reopen TUN/TAP device or run up/down scripts across
 SIGUSR1 or --ping-restart restarts.
 
-Defaults to @samp{#t}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} boolean fast-io?
+@item @code{fast-io?} (default: @code{#f}) (type: boolean)
 (Experimental) Optimize TUN/TAP/UDP I/O writes by avoiding a call to
 poll/epoll/select prior to the write operation.
 
-Defaults to @samp{#f}.
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} number verbosity
+@item @code{verbosity} (default: @code{3}) (type: number)
 Verbosity level.
 
-Defaults to @samp{3}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} tls-auth-client 
tls-auth
+@item @code{tls-auth} (default: @code{#f}) (type: tls-auth-client)
 Add an additional layer of HMAC authentication on top of the TLS control
 channel to protect against DoS attacks.
 
-Defaults to @samp{#f}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} maybe-string 
auth-user-pass
+@item @code{auth-user-pass} (type: maybe-string)
 Authenticate with server using username/password.  The option is a file
-containing username/password on 2 lines.  Do not use a file-like object as it
-would be added to the store and readable by any user.
+containing username/password on 2 lines.  Do not use a file-like object
+as it would be added to the store and readable by any user.
 
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} key-usage 
verify-key-usage?
+@item @code{verify-key-usage?} (default: @code{#t}) (type: key-usage)
 Whether to check the server certificate has server usage extension.
 
-Defaults to @samp{#t}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} bind bind?
+@item @code{bind?} (default: @code{#f}) (type: bind)
 Bind to a specific local port number.
 
-Defaults to @samp{#f}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} resolv-retry 
resolv-retry?
+@item @code{resolv-retry?} (default: @code{#t}) (type: resolv-retry)
 Retry resolving server address.
 
-Defaults to @samp{#t}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-client-configuration} parameter} openvpn-remote-list 
remote
+@item @code{remote} (default: @code{()}) (type: openvpn-remote-list)
 A list of remote servers to connect to.
 
-Defaults to @samp{()}.
-
+@deftp {Data Type} openvpn-remote-configuration
 Available @code{openvpn-remote-configuration} fields are:
 
-@deftypevr {@code{openvpn-remote-configuration} parameter} string name
+@table @asis
+@item @code{name} (default: @code{"my-server"}) (type: string)
 Server name.
 
-Defaults to @samp{"my-server"}.
+@item @code{port} (default: @code{1194}) (type: number)
+Port number the server listens to.
 
-@end deftypevr
+@end table
 
-@deftypevr {@code{openvpn-remote-configuration} parameter} number port
-Port number the server listens to.
+@end deftp
 
-Defaults to @samp{1194}.
+@end table
 
-@end deftypevr
+@end deftp
 
-@end deftypevr
 @c %end of automatic openvpn-client documentation
 
 @c %automatically generated documentation
 
+@deftp {Data Type} openvpn-server-configuration
 Available @code{openvpn-server-configuration} fields are:
 
-@deftypevr {@code{openvpn-server-configuration} parameter} package openvpn
+@table @asis
+@item @code{openvpn} (default: @code{openvpn}) (type: file-like)
 The OpenVPN package.
 
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} string pid-file
+@item @code{pid-file} (default: @code{"/var/run/openvpn/openvpn.pid"}) (type: 
string)
 The OpenVPN pid file.
 
-Defaults to @samp{"/var/run/openvpn/openvpn.pid"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} proto proto
+@item @code{proto} (default: @code{udp}) (type: proto)
 The protocol (UDP or TCP) used to open a channel between clients and
 servers.
 
-Defaults to @samp{udp}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} dev dev
+@item @code{dev} (default: @code{tun}) (type: dev)
 The device type used to represent the VPN connection.
 
-Defaults to @samp{tun}.
-
-@end deftypevr
-
-If you do not have some of these files (eg.@: you use a username and
-password), you can disable any of the following three fields by setting
-it to @code{*unspecified*}.
-
-@deftypevr {@code{openvpn-server-configuration} parameter} maybe-string ca
+@item @code{ca} (default: @code{"/etc/openvpn/ca.crt"}) (type: maybe-string)
 The certificate authority to check connections against.
 
-Defaults to @samp{"/etc/openvpn/ca.crt"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} maybe-string cert
+@item @code{cert} (default: @code{"/etc/openvpn/client.crt"}) (type: 
maybe-string)
 The certificate of the machine the daemon is running on.  It should be
 signed by the authority given in @code{ca}.
 
-Defaults to @samp{"/etc/openvpn/client.crt"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} maybe-string key
-The key of the machine the daemon is running on.  It must be the key whose
-certificate is @code{cert}.
-
-Defaults to @samp{"/etc/openvpn/client.key"}.
-
-@end deftypevr
+@item @code{key} (default: @code{"/etc/openvpn/client.key"}) (type: 
maybe-string)
+The key of the machine the daemon is running on.  It must be the key
+whose certificate is @code{cert}.
 
-@deftypevr {@code{openvpn-server-configuration} parameter} boolean comp-lzo?
+@item @code{comp-lzo?} (default: @code{#t}) (type: boolean)
 Whether to use the lzo compression algorithm.
 
-Defaults to @samp{#t}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-key?
+@item @code{persist-key?} (default: @code{#t}) (type: boolean)
 Don't re-read key files across SIGUSR1 or --ping-restart.
 
-Defaults to @samp{#t}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} boolean persist-tun?
+@item @code{persist-tun?} (default: @code{#t}) (type: boolean)
 Don't close and reopen TUN/TAP device or run up/down scripts across
 SIGUSR1 or --ping-restart restarts.
 
-Defaults to @samp{#t}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} boolean fast-io?
+@item @code{fast-io?} (default: @code{#f}) (type: boolean)
 (Experimental) Optimize TUN/TAP/UDP I/O writes by avoiding a call to
 poll/epoll/select prior to the write operation.
 
-Defaults to @samp{#f}.
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} number verbosity
+@item @code{verbosity} (default: @code{3}) (type: number)
 Verbosity level.
 
-Defaults to @samp{3}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} tls-auth-server 
tls-auth
+@item @code{tls-auth} (default: @code{#f}) (type: tls-auth-server)
 Add an additional layer of HMAC authentication on top of the TLS control
 channel to protect against DoS attacks.
 
-Defaults to @samp{#f}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} number port
+@item @code{port} (default: @code{1194}) (type: number)
 Specifies the port number on which the server listens.
 
-Defaults to @samp{1194}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} ip-mask server
+@item @code{server} (default: @code{"10.8.0.0 255.255.255.0"}) (type: ip-mask)
 An ip and mask specifying the subnet inside the virtual network.
 
-Defaults to @samp{"10.8.0.0 255.255.255.0"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} cidr6 server-ipv6
+@item @code{server-ipv6} (default: @code{#f}) (type: cidr6)
 A CIDR notation specifying the IPv6 subnet inside the virtual network.
 
-Defaults to @samp{#f}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} string dh
+@item @code{dh} (default: @code{"/etc/openvpn/dh2048.pem"}) (type: string)
 The Diffie-Hellman parameters file.
 
-Defaults to @samp{"/etc/openvpn/dh2048.pem"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} string 
ifconfig-pool-persist
+@item @code{ifconfig-pool-persist} (default: @code{"/etc/openvpn/ipp.txt"}) 
(type: string)
 The file that records client IPs.
 
-Defaults to @samp{"/etc/openvpn/ipp.txt"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} gateway 
redirect-gateway?
+@item @code{redirect-gateway?} (default: @code{#f}) (type: gateway)
 When true, the server will act as a gateway for its clients.
 
-Defaults to @samp{#f}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} boolean 
client-to-client?
+@item @code{client-to-client?} (default: @code{#f}) (type: boolean)
 When true, clients are allowed to talk to each other inside the VPN.
 
-Defaults to @samp{#f}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} keepalive keepalive
+@item @code{keepalive} (default: @code{(10 120)}) (type: keepalive)
 Causes ping-like messages to be sent back and forth over the link so
 that each side knows when the other side has gone down.  @code{keepalive}
 requires a pair.  The first element is the period of the ping sending,
 and the second element is the timeout before considering the other side
 down.
 
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} number max-clients
+@item @code{max-clients} (default: @code{100}) (type: number)
 The maximum number of clients.
 
-Defaults to @samp{100}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} string status
+@item @code{status} (default: @code{"/var/run/openvpn/status"}) (type: string)
 The status file.  This file shows a small report on current connection.
 It is truncated and rewritten every minute.
 
-Defaults to @samp{"/var/run/openvpn/status"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-server-configuration} parameter} openvpn-ccd-list 
client-config-dir
+@item @code{client-config-dir} (default: @code{()}) (type: openvpn-ccd-list)
 The list of configuration for some clients.
 
-Defaults to @samp{()}.
-
-Available @code{openvpn-ccd-configuration} fields are:
-
-@deftypevr {@code{openvpn-ccd-configuration} parameter} string name
-Client name.
-
-Defaults to @samp{"client"}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask iroute
-Client own network
-
-Defaults to @samp{#f}.
-
-@end deftypevr
-
-@deftypevr {@code{openvpn-ccd-configuration} parameter} ip-mask ifconfig-push
-Client VPN IP.
-
-Defaults to @samp{#f}.
-
-@end deftypevr
+@end table
 
-@end deftypevr
+@end deftp
 
 @c %end of automatic openvpn-server documentation
 
@@ -31512,7 +31305,7 @@ Each parameter definition is preceded by its type; for 
example,
 @samp{boolean foo} indicates that the @code{foo} parameter should be
 specified as a boolean.  Types starting with @code{maybe-} denote
 parameters that won't show up in TLP config file when their value is
-left unset, or is explicitly set to the @code{*unspecified*} value.
+left unset, or is explicitly set to the @code{'unspecified} value.
 
 @c The following documentation was initially generated by
 @c (generate-tlp-documentation) in (gnu services pm).  Manually maintained
@@ -39129,7 +38922,7 @@ macro which is a shorthand of this.
 Sometimes a field should not be serialized if the user doesn’t specify a
 value.  To achieve this, you can use the @code{define-maybe} macro to
 define a ``maybe type''; if the value of a maybe type is left unset, or
-is set to the @code{*unspecified*} value, then it will not be
+is set to the @code{'unspecified} value, then it will not be
 serialized.
 
 When defining a ``maybe type'', the corresponding serializer for the
diff --git a/gnu/services/configuration.scm b/gnu/services/configuration.scm
index e3c101d042..3758b4e09a 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 @@ (define (define-maybe-helper serialize? prefix syn)
                                     (id #'stem #'serialize-maybe- #'stem))))
        #`(begin
            (define (maybe-stem? val)
-             (or (unspecified? val)
-                 (stem? val)))
+             (or (eq? val 'unspecified) (stem? val)))
            #,@(if serialize?
                   (list #'(define (serialize-maybe-stem field-name val)
                             (if (stem? val)
@@ -171,10 +170,10 @@ (define (normalize-field-type+def s)
      (values #'(field-type def)))
     ((field-type)
      (identifier? #'field-type)
-     (values #'(field-type *unspecified*)))
+     (values #'(field-type 'unspecified)))
     (field-type
      (identifier? #'field-type)
-     (values #'(field-type *unspecified*)))))
+     (values #'(field-type 'unspecified)))))
 
 (define (define-configuration-helper serialize? serializer-prefix syn)
   (syntax-case syn ()
@@ -262,7 +261,7 @@ (define #,(id #'stem #'stem #'-fields)
                         (lambda ()
                           (display '#,(id #'stem #'% #'stem))
                           (if (eq? (syntax->datum field-default)
-                                   '*unspecified*)
+                                   'unspecified)
                               (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..8110bb0cce 100644
--- a/gnu/services/file-sharing.scm
+++ b/gnu/services/file-sharing.scm
@@ -115,7 +115,7 @@ (define-maybe string)
 (set! serialize-maybe-string
   (lambda (field-name val)
     (serialize-string field-name
-                      (if (unspecified? val)
+                      (if (eq? val 'unspecified)
                           ""
                           val))))
 
@@ -180,7 +180,7 @@ (define (serialize-file-object field-name val)
 (define-maybe file-object)
 (set! serialize-maybe-file-object
   (lambda (field-name val)
-    (if (unspecified? val)
+    (if (eq? val 'unspecified)
         (serialize-string field-name "")
         (serialize-file-object field-name val))))
 
diff --git a/gnu/services/messaging.scm b/gnu/services/messaging.scm
index 651f90adb2..abe814e7f5 100644
--- a/gnu/services/messaging.scm
+++ b/gnu/services/messaging.scm
@@ -90,7 +90,7 @@ (define (make-pred arg)
                      ((new-def ...)
                       (map (lambda (def target)
                              (if (eq? 'common (syntax->datum target))
-                                 #'*unspecified* def))
+                                 #''unspecified def))
                            #'(def ...) #'(target ...)))
                      ((new-doc ...)
                       (map (lambda (doc target)
@@ -200,7 +200,7 @@ (define (serialize-file-object-list field-name val)
 (define-maybe file-object-list)
 
 (define (raw-content? val)
-  (not (unspecified? val)))
+  (not (eq? val 'unspecified)))
 (define (serialize-raw-content field-name val)
   val)
 (define-maybe raw-content)
@@ -474,12 +474,12 @@ (define-all-configurations prosody-configuration
      global)
 
     (http-max-content-size
-     (maybe-non-negative-integer *unspecified*)
+     (maybe-non-negative-integer 'unspecified)
      "Maximum allowed size of the HTTP body (in bytes)."
      common)
 
     (http-external-url
-     (maybe-string *unspecified*)
+     (maybe-string 'unspecified)
      "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 @@ (define-all-configurations prosody-configuration
      int-component)
 
     (mod-muc
-     (maybe-mod-muc-configuration *unspecified*)
+     (maybe-mod-muc-configuration 'unspecified)
      "Multi-user chat (MUC) is Prosody's module for allowing you to create
 hosted chatrooms/conferences for XMPP users.
 
@@ -573,7 +573,7 @@ (define-all-configurations prosody-configuration
      ext-component)
 
     (raw-content
-     (maybe-raw-content *unspecified*)
+     (maybe-raw-content 'unspecified)
      "Raw content that will be added to the configuration file."
      common)))
 
diff --git a/gnu/services/networking.scm b/gnu/services/networking.scm
index b555c46040..a5f0924984 100644
--- a/gnu/services/networking.scm
+++ b/gnu/services/networking.scm
@@ -772,11 +772,11 @@ (define-configuration/no-serialization 
opendht-configuration
 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{'unspecified} 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..f099b60a0e 100644
--- a/gnu/services/telephony.scm
+++ b/gnu/services/telephony.scm
@@ -307,7 +307,7 @@ (define (jami-shepherd-services config)
          (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? 'unspecified accounts))))
 
     (with-extensions (list guile-packrat ;used by guile-ac-d-bus
                            guile-ac-d-bus
@@ -649,7 +649,7 @@ (define (archive-name->username archive)
                                           account-details)
                            (let ((username (archive-name->username
                                             archive)))
-                             (when (not (unspecified? allowed-contacts))
+                             (when (not (eq? 'unspecified allowed-contacts))
                                ;; Reject calls from unknown contacts.
                                (set-account-details
                                 '(("DHT.PublicInCalls" . "false")) username)
@@ -659,7 +659,7 @@ (define (archive-name->username archive)
                                ;; Add allowed ones.
                                (for-each (cut add-contact <> username)
                                          allowed-contacts))
-                             (when (not (unspecified? moderators))
+                             (when (not (eq? 'unspecified moderators))
                                ;; Disable the 'AllModerators' property.
                                (set-all-moderators #f username)
                                ;; Remove all moderators.
diff --git a/tests/services/configuration.scm b/tests/services/configuration.scm
index 6268525317..9fea65ba58 100644
--- a/tests/services/configuration.scm
+++ b/tests/services/configuration.scm
@@ -151,9 +151,9 @@ (define-configuration 
config-with-maybe-string/no-serialization
   (not (defined? 'serialize-maybe-string)))
 
 (test-assert "maybe type, no default"
-  (unspecified?
-   (config-with-maybe-string/no-serialization-name
-    (config-with-maybe-string/no-serialization))))
+  (eq? 'unspecified
+       (config-with-maybe-string/no-serialization-name
+        (config-with-maybe-string/no-serialization))))
 
 (test-assert "maybe type, with default"
   (equal?
-- 
2.36.1