UX: better error message if moderator is not allowed to invite to group

UX: do not show invite to group option if mod is not owner of any group

app/assets/javascripts/discourse/app/components/invite-link-panel.js

@@ -1,7 +1,7 @@
 import I18n from "I18n";
 import Component from "@ember/component";
 import Group from "discourse/models/group";
-import { readOnly } from "@ember/object/computed";
+import { alias, readOnly } from "@ember/object/computed";
 import { action } from "@ember/object";
 import discourseComputed from "discourse-common/utils/decorators";
 import Invite from "discourse/models/invite";
@@ -17,6 +17,8 @@ export default Component.extend({
   groupIds: null,
   allGroups: null,
 
+  isAdmin: alias("currentUser.admin"),
+
   init() {
     this._super(...arguments);
 
@@ -43,6 +45,13 @@ export default Component.extend({
 
   errorMessage: I18n.t("user.invited.invite_link.error"),
 
+  @discourseComputed("isAdmin", "inviteModel.group_users")
+  showGroups(isAdmin, groupUsers) {
+    return (
+      isAdmin || (groupUsers && groupUsers.some(groupUser => groupUser.owner))
+    );
+  },
+
   reset() {
     this.setProperties({
       maxRedemptionAllowed: 5,

app/assets/javascripts/discourse/app/templates/components/invite-link-panel.hbs

@@ -9,6 +9,7 @@
     {{generated-invite-link link=inviteModel.inviteLink}}
   {{else}}
 
+    {{#if showGroups}}
       <div class="group-access-control">
         <label class="instructions">
           {{i18n "topic.automatically_add_to_groups"}}
@@ -19,6 +20,7 @@
           labelProperty="name"
           onChange=(action (mut groupIds))}}
       </div>
+    {{/if}}
 
     <div class="max-redemptions-allowed">
       <label class="instructions">

app/controllers/invites_controller.rb

@@ -122,7 +122,9 @@ class InvitesController < ApplicationController
       group_ids: params[:group_ids],
       group_names: params[:group_names]
     )
-    guardian.ensure_can_invite_to_forum!(groups)
+    if !guardian.can_invite_to_forum?(groups)
+      raise StandardError.new I18n.t("invite.cant_invite_to_group")
+    end
     group_ids = groups.map(&:id)
 
     if is_single_invite
@@ -142,7 +144,6 @@ class InvitesController < ApplicationController
       end
     end
 
-    begin
     invite_link = if is_single_invite
       Invite.generate_single_use_invite_link(params[:email], current_user, topic, group_ids)
     else
@@ -161,7 +162,6 @@ class InvitesController < ApplicationController
   rescue => e
     render json: { errors: [e.message] }, status: 422
   end
-  end
 
   def destroy
     params.require(:id)

config/locales/server.en.yml

@@ -229,6 +229,7 @@ en:
     error_message: "There was an error accepting invite. Please contact the site's administrator."
     user_exists: "There's no need to invite <b>%{email}</b>, they <a href='%{base_path}/u/%{username}/summary'>already have an account!</a>"
     confirm_email: "<p>You’re almost done! We sent an activation mail to your email address. Please follow the instructions in the mail to activate your account.</p><p>If it doesn’t arrive, check your spam folder.</p>"
+    cant_invite_to_group: "You are not allowed to invite users to specified group(s). Make sure you are owner of the group(s) you are trying to invite to."
 
   bulk_invite:
     file_should_be_csv: "The uploaded file should be of csv format."