FIX: Invite redemption error if user had already redeemed

app/assets/javascripts/discourse/app/controllers/invites-show.js

@@ -31,6 +31,9 @@ export default Controller.extend(
     accountEmail: alias("email"),
     existingUserId: readOnly("model.existing_user_id"),
     existingUserCanRedeem: readOnly("model.existing_user_can_redeem"),
+    existingUserCanRedeemError: readOnly(
+      "model.existing_user_can_redeem_error"
+    ),
     existingUserRedeeming: bool("existingUserId"),
     hiddenEmail: alias("model.hidden_email"),
     emailVerifiedByLink: alias("model.email_verified_by_link"),

app/assets/javascripts/discourse/app/templates/invites/show.hbs

@@ -135,7 +135,7 @@
               {{#if this.existingUserCanRedeem}}
                 <DButton @class="btn-primary" @action={{action "submit"}} @type="submit" @disabled={{this.submitDisabled}} @label="invites.accept_invite" />
               {{else}}
-                <div class="alert alert-error">{{i18n "invites.existing_user_cannot_redeem"}}</div>
+                <div class="alert alert-error">{{this.existingUserCanRedeemError}}</div>
               {{/if}}
             {{/if}}
           {{/if}}

app/controllers/invites_controller.rb

@@ -408,6 +408,7 @@ def show_invite(invite)
     if current_user
       info[:existing_user_id] = current_user.id
       info[:existing_user_can_redeem] = invite.can_be_redeemed_by?(current_user)
+      info[:existing_user_can_redeem_error] = existing_user_can_redeem_error(invite)
       info[:email] = current_user.email
       info[:username] = current_user.username
     end
@@ -493,4 +494,13 @@ def create_topic_invite_notifications(invite, user)
       end
     end
   end
+
+  def existing_user_can_redeem_error(invite)
+    return if invite.can_be_redeemed_by?(current_user)
+    if invite.invited_users.exists?(user: current_user)
+      I18n.t("invite.existing_user_already_redemeed")
+    else
+      I18n.t("invite.existing_user_cannot_redeem")
+    end
+  end
 end

app/models/invite.rb

@@ -90,6 +90,10 @@ def redeemable?
     !redeemed? && !expired? && !deleted_at? && !destroyed? && link_valid?
   end
 
+  def redeemed_by_user?(redeeming_user)
+    self.invited_users.exists?(user: redeeming_user)
+  end
+
   def redeemed?
     if is_invite_link?
       redemption_count >= max_redemptions_allowed
@@ -109,7 +113,7 @@ def domain_matches?(email)
 
   def can_be_redeemed_by?(user)
     return false if !self.redeemable?
-    return true if self.email.blank? && self.domain.blank?
+    return false if redeemed_by_user?(user)
     return true if self.email.present? && email_matches?(user.email)
     self.domain.present? && domain_matches?(user.email)
   end

config/locales/client.en.yml

@@ -2097,7 +2097,6 @@ en:
       name_label: "Name"
       password_label: "Password"
       existing_user_can_redeem: "Redeem your invitation to a topic or group."
-      existing_user_cannot_redeem: "This invitation cannot be redeemed. Please ask the person who invited you to send you a new invitation."
 
     password_reset:
       continue: "Continue to %{site_name}"

config/locales/server.en.yml

@@ -250,6 +250,8 @@ en:
       <p>Otherwise please <a href="%{base_url}/password-reset">Reset Password</a>.</p>
     not_found_template_link: |
       <p>This invitation to <a href="%{base_url}">%{site_name}</a> can no longer be redeemed. Please ask the person who invited you to send you a new invitation.</p>
+    existing_user_cannot_redeem: "This invitation cannot be redeemed. Please ask the person who invited you to send you a new invitation."
+    existing_user_already_redemeed: "You have already redeemed this invite link."
     user_exists: "There's no need to invite <b>%{email}</b>, they already have an account!"
     invite_exists: "You already invited <b>%{email}</b>."
     invalid_email: "%{email} isn't a valid email address."

spec/requests/invites_controller_spec.rb

@@ -126,6 +126,7 @@
           json = JSON.parse(element.current_scope.attribute('data-preloaded').value)
           invite_info = JSON.parse(json['invite_info'])
           expect(invite_info['existing_user_can_redeem']).to eq(false)
+          expect(invite_info['existing_user_can_redeem_error']).to eq(I18n.t("invite.existing_user_cannot_redeem"))
         end
       end
 
@@ -141,6 +142,22 @@
           expect(invite_info['existing_user_can_redeem']).to eq(false)
         end
       end
+
+      it "does not allow the user to accept the invite when a multi-use invite link has already been redeemed by the user" do
+        invite.update!(email: nil, max_redemptions_allowed: 10)
+        expect(invite.redeem(redeeming_user: user)).not_to eq(nil)
+
+        get "/invites/#{invite.invite_key}"
+        expect(response.status).to eq(200)
+
+        expect(response.body).to have_tag('div#data-preloaded') do |element|
+          json = JSON.parse(element.current_scope.attribute('data-preloaded').value)
+          invite_info = JSON.parse(json['invite_info'])
+          expect(invite_info['existing_user_id']).to eq(user.id)
+          expect(invite_info['existing_user_can_redeem']).to eq(false)
+          expect(invite_info['existing_user_can_redeem_error']).to eq(I18n.t("invite.existing_user_already_redemeed"))
+        end
+      end
     end
 
     it 'fails if invite does not exist' do