Better locale management in the admin console

Closes #39934

Signed-off-by: rmartinc <rmartinc@redhat.com>

js/apps/admin-ui/maven-resources/theme/keycloak.v2/admin/messages/messages_en.properties

@@ -2888,6 +2888,7 @@ emptyPermissionInstructions=If you want to create a permission, please click the
 webAuthnPolicyAvoidSameAuthenticatorRegisterHelp=Avoid registering an authenticator that has already been registered.
 memberofLdapAttribute=Member-of LDAP attribute
 supportedLocales=Supported locales
+invalidLocale=Invalid locale selected
 showPasswordDataValue=Value
 webAuthnPolicyAttestationConveyancePreference=Attestation conveyance preference
 copyOf=Copy of {{name}}
@@ -3490,4 +3491,4 @@ fullNameClaimHelp=The name of the claim from the JSON document returned by the u
 givenNameClaim=Given name Claim
 givenNameClaimHelp=The name of the claim from the JSON document returned by the user profile endpoint representing the user's given name. If not provided, defaults to `given_name`.
 familyNameClaim=Family name Claim
-familyNameClaimHelp=The name of the claim from the JSON document returned by the user profile endpoint representing the user's family name. If not provided, defaults to `family_name`.
+familyNameClaimHelp=The name of the claim from the JSON document returned by the user profile endpoint representing the user's family name. If not provided, defaults to `family_name`.

js/apps/admin-ui/src/realm-settings/localization/LocalizationTab.tsx

@@ -98,8 +98,15 @@ export const LocalizationTab = ({
                   name="supportedLocales"
                   isScrollable
                   label={t("supportedLocales")}
+                  labelIcon={t("supportedLocalesHelp")}
                   controller={{
                     defaultValue: defaultSupportedLocales,
+                    rules: {
+                      required: t("required"),
+                      validate: (value: string[]) =>
+                        value.every((v) => allLocales.includes(v)) ||
+                        t("invalidLocale"),
+                    },
                   }}
                   variant="typeaheadMulti"
                   placeholderText={t("selectLocales")}
@@ -111,8 +118,14 @@ export const LocalizationTab = ({
                 <SelectControl
                   name="defaultLocale"
                   label={t("defaultLocale")}
+                  labelIcon={t("defaultLocaleHelp")}
                   controller={{
                     defaultValue: DEFAULT_LOCALE,
+                    rules: {
+                      required: t("required"),
+                      validate: (value: string) =>
+                        watchSupportedLocales?.includes(value) || t("required"),
+                    },
                   }}
                   data-testid="select-default-locale"
                   options={watchSupportedLocales!.map((l) => ({

server-spi-private/src/main/java/org/keycloak/models/utils/ModelToRepresentation.java

@@ -564,7 +564,10 @@ public class ModelToRepresentation {
         }
 
         rep.setInternationalizationEnabled(realm.isInternationalizationEnabled());
-        rep.setSupportedLocales(realm.getSupportedLocalesStream().collect(Collectors.toSet()));
+        Set<String> supportedLocales = realm.getSupportedLocalesStream().collect(Collectors.toSet());
+        if (!supportedLocales.isEmpty()) {
+            rep.setSupportedLocales(supportedLocales);
+        }
         rep.setDefaultLocale(realm.getDefaultLocale());
         if (internal) {
             exportAuthenticationFlows(session, realm, rep);