17 files changed, 55 insertions, 13 deletions
diff --git a/lib/tests/modules.sh b/lib/tests/modules.sh
index eadaa0521b35..cf344122cf4e 100755
--- a/lib/tests/modules.sh
+++ b/lib/tests/modules.sh
@@ -71,6 +71,15 @@ checkConfigError 'The option value .* in .* is not of type.*positive integer.*'
 checkConfigOutput "42" config.value ./declare-int-between-value.nix ./define-value-int-positive.nix
 checkConfigError 'The option value .* in .* is not of type.*between.*-21 and 43.*inclusive.*' config.value ./declare-int-between-value.nix ./define-value-int-negative.nix
 
+# Check either types
+# types.either
+checkConfigOutput "42" config.value ./declare-either.nix ./define-value-int-positive.nix
+checkConfigOutput "\"24\"" config.value ./declare-either.nix ./define-value-string.nix
+# types.oneOf
+checkConfigOutput "42" config.value ./declare-oneOf.nix ./define-value-int-positive.nix
+checkConfigOutput "[ ]" config.value ./declare-oneOf.nix ./define-value-list.nix
+checkConfigOutput "\"24\"" config.value ./declare-oneOf.nix ./define-value-string.nix
+
 # Check mkForce without submodules.
 set -- config.enable ./declare-enable.nix ./define-enable.nix
 checkConfigOutput "true" "$@"
diff --git a/lib/tests/modules/declare-either.nix b/lib/tests/modules/declare-either.nix
new file mode 100644
index 000000000000..5a0fa978a138
--- /dev/null
+++ b/lib/tests/modules/declare-either.nix
@@ -0,0 +1,5 @@
+{ lib, ... }: {
+  options.value = lib.mkOption {
+    type = lib.types.either lib.types.int lib.types.str;
+  };
+}
diff --git a/lib/tests/modules/declare-oneOf.nix b/lib/tests/modules/declare-oneOf.nix
new file mode 100644
index 000000000000..df092a14f81e
--- /dev/null
+++ b/lib/tests/modules/declare-oneOf.nix
@@ -0,0 +1,9 @@
+{ lib, ... }: {
+  options.value = lib.mkOption {
+    type = lib.types.oneOf [
+      lib.types.int
+      (lib.types.listOf lib.types.int)
+      lib.types.str
+    ];
+  };
+}
diff --git a/lib/types.nix b/lib/types.nix
index e22bcd326c86..9c00656ab918 100644
--- a/lib/types.nix
+++ b/lib/types.nix
@@ -443,6 +443,13 @@ rec {
       functor = (defaultFunctor name) // { wrapped = [ t1 t2 ]; };
     };
 
+    # Any of the types in the given list
+    oneOf = ts:
+      let
+        head' = if ts == [] then throw "types.oneOf needs to get at least one type in its argument" else head ts;
+        tail' = tail ts;
+      in foldl' either head' tail';
+
     # Either value of type `finalType` or `coercedType`, the latter is
     # converted to `finalType` using `coerceFunc`.
     coercedTo = coercedType: coerceFunc: finalType:
diff --git a/nixos/doc/manual/development/option-types.xml b/nixos/doc/manual/development/option-types.xml
index 069cc36573d8..8fcbb627342b 100644
--- a/nixos/doc/manual/development/option-types.xml
+++ b/nixos/doc/manual/development/option-types.xml
@@ -348,6 +348,18 @@
    </varlistentry>
    <varlistentry>
     <term>
+     <varname>types.oneOf</varname> [ <replaceable>t1</replaceable> <replaceable>t2</replaceable> ... ]
+    </term>
+    <listitem>
+     <para>
+      Type <replaceable>t1</replaceable> or type <replaceable>t2</replaceable> and so forth,
+      e.g. <literal>with types; oneOf [ int str bool ]</literal>. Multiple definitions
+      cannot be merged.
+     </para>
+    </listitem>
+   </varlistentry>
+   <varlistentry>
+    <term>
      <varname>types.coercedTo</varname> <replaceable>from</replaceable> <replaceable>f</replaceable> <replaceable>to</replaceable>
     </term>
     <listitem>
diff --git a/nixos/modules/services/backup/automysqlbackup.nix b/nixos/modules/services/backup/automysqlbackup.nix
index b845f370fb70..1884f3536a97 100644
--- a/nixos/modules/services/backup/automysqlbackup.nix
+++ b/nixos/modules/services/backup/automysqlbackup.nix
@@ -41,7 +41,7 @@ in
       };
 
       config = mkOption {
-        type = with types; attrsOf (either (either str (either int bool)) (listOf str));
+        type = with types; attrsOf (oneOf [ str int bool (listOf str) ]);
         default = {};
         description = ''
           automysqlbackup configuration. Refer to
diff --git a/nixos/modules/services/games/minecraft-server.nix b/nixos/modules/services/games/minecraft-server.nix
index 39a68f4b5536..eb9288fca586 100644
--- a/nixos/modules/services/games/minecraft-server.nix
+++ b/nixos/modules/services/games/minecraft-server.nix
@@ -118,7 +118,7 @@ in {
       };
 
       serverProperties = mkOption {
-        type = with types; attrsOf (either bool (either int str));
+        type = with types; attrsOf (oneOf [ bool int str ]);
         default = {};
         example = literalExample ''
           {
diff --git a/nixos/modules/services/mail/davmail.nix b/nixos/modules/services/mail/davmail.nix
index 5b5cc294e5c7..374a3dd75c1c 100644
--- a/nixos/modules/services/mail/davmail.nix
+++ b/nixos/modules/services/mail/davmail.nix
@@ -7,7 +7,7 @@ let
   cfg = config.services.davmail;
 
   configType = with types;
-    either (either (attrsOf configType) str) (either int bool) // {
+    oneOf [ (attrsOf configType) str int bool ] // {
       description = "davmail config type (str, int, bool or attribute set thereof)";
     };
 
diff --git a/nixos/modules/services/mail/postfix.nix b/nixos/modules/services/mail/postfix.nix
index dab1b29aa4be..2b08ab1e6aa6 100644
--- a/nixos/modules/services/mail/postfix.nix
+++ b/nixos/modules/services/mail/postfix.nix
@@ -447,7 +447,7 @@ in
       };
 
       config = mkOption {
-        type = with types; attrsOf (either bool (either str (listOf str)));
+        type = with types; attrsOf (oneOf [ bool str (listOf str) ]);
         description = ''
           The main.cf configuration file as key value set.
         '';
diff --git a/nixos/modules/services/mail/rspamd.nix b/nixos/modules/services/mail/rspamd.nix
index 5541b8b79b7e..e59d5715de05 100644
--- a/nixos/modules/services/mail/rspamd.nix
+++ b/nixos/modules/services/mail/rspamd.nix
@@ -331,7 +331,7 @@ in
         };
 
         config = mkOption {
-          type = with types; attrsOf (either bool (either str (listOf str)));
+          type = with types; attrsOf (oneOf [ bool str (listOf str) ]);
           description = ''
             Addon to postfix configuration
           '';
diff --git a/nixos/modules/services/mail/rss2email.nix b/nixos/modules/services/mail/rss2email.nix
index a123736005ab..df454abc8267 100644
--- a/nixos/modules/services/mail/rss2email.nix
+++ b/nixos/modules/services/mail/rss2email.nix
@@ -30,7 +30,7 @@ in {
       };
 
       config = mkOption {
-        type = with types; attrsOf (either str (either int bool));
+        type = with types; attrsOf (oneOf [ str int bool ]);
         default = {};
         description = ''
           The configuration to give rss2email.
diff --git a/nixos/modules/services/networking/znc/default.nix b/nixos/modules/services/networking/znc/default.nix
index 46bff6954cdd..05f97bfa539f 100644
--- a/nixos/modules/services/networking/znc/default.nix
+++ b/nixos/modules/services/networking/znc/default.nix
@@ -62,9 +62,9 @@ let
       concatStringsSep "\n" (toLines cfg.config);
 
   semanticTypes = with types; rec {
-    zncAtom = nullOr (either (either int bool) str);
+    zncAtom = nullOr (oneOf [ int bool str ]);
     zncAttr = attrsOf (nullOr zncConf);
-    zncAll = either (either zncAtom (listOf zncAtom)) zncAttr;
+    zncAll = oneOf [ zncAtom (listOf zncAtom) zncAttr ];
     zncConf = attrsOf (zncAll // {
       # Since this is a recursive type and the description by default contains
       # the description of its subtypes, infinite recursion would occur without
diff --git a/nixos/modules/services/security/bitwarden_rs/default.nix b/nixos/modules/services/security/bitwarden_rs/default.nix
index bb036ee020f4..80fd65891ff8 100644
--- a/nixos/modules/services/security/bitwarden_rs/default.nix
+++ b/nixos/modules/services/security/bitwarden_rs/default.nix
@@ -36,7 +36,7 @@ in {
     };
 
     config = mkOption {
-      type = attrsOf (nullOr (either (either bool int) str));
+      type = attrsOf (nullOr (oneOf [ bool int str ]));
       default = {};
       example = literalExample ''
         {
diff --git a/nixos/modules/services/web-apps/limesurvey.nix b/nixos/modules/services/web-apps/limesurvey.nix
index 5b2f3875aaa9..84a94fc446e5 100644
--- a/nixos/modules/services/web-apps/limesurvey.nix
+++ b/nixos/modules/services/web-apps/limesurvey.nix
@@ -14,7 +14,7 @@ let
 
   pkg = pkgs.limesurvey;
 
-  configType = with types; either (either (attrsOf configType) str) (either int bool) // {
+  configType = with types; oneOf [ (attrsOf configType) str int bool ] // {
     description = "limesurvey config type (str, int, bool or attribute set thereof)";
   };
 
diff --git a/nixos/modules/services/x11/compton.nix b/nixos/modules/services/x11/compton.nix
index c02c9bfd94e8..a94a76ff0c0f 100644
--- a/nixos/modules/services/x11/compton.nix
+++ b/nixos/modules/services/x11/compton.nix
@@ -215,7 +215,7 @@ in {
     };
 
     settings = let
-      configTypes = with types; either bool (either int (either float str));
+      configTypes = with types; oneOf [ bool int float str ];
       # types.loaOf converts lists to sets
       loaOf = t: with types; either (listOf t) (attrsOf t);
     in mkOption {
diff --git a/nixos/modules/system/boot/systemd-unit-options.nix b/nixos/modules/system/boot/systemd-unit-options.nix
index ee4ae845a7d5..c1f2c98afcd8 100644
--- a/nixos/modules/system/boot/systemd-unit-options.nix
+++ b/nixos/modules/system/boot/systemd-unit-options.nix
@@ -226,7 +226,7 @@ in rec {
 
     environment = mkOption {
       default = {};
-      type = with types; attrsOf (nullOr (either str (either path package)));
+      type = with types; attrsOf (nullOr (oneOf [ str path package ]));
       example = { PATH = "/foo/bar/bin"; LANG = "nl_NL.UTF-8"; };
       description = "Environment variables passed to the service's processes.";
     };
diff --git a/nixos/modules/system/boot/systemd.nix b/nixos/modules/system/boot/systemd.nix
index cf35504e5182..0393291c0c39 100644
--- a/nixos/modules/system/boot/systemd.nix
+++ b/nixos/modules/system/boot/systemd.nix
@@ -520,7 +520,7 @@ in
     };
 
     systemd.globalEnvironment = mkOption {
-      type = with types; attrsOf (nullOr (either str (either path package)));
+      type = with types; attrsOf (nullOr (oneOf [ str path package ]));
       default = {};
       example = { TZ = "CET"; };
       description = ''