Display appropriate errors when personal access token creation/revocation fails.

app/controllers/profiles/personal_access_tokens_controller.rb

 class Profiles::PersonalAccessTokensController < Profiles::ApplicationController
+  before_action :load_personal_access_tokens, only: :index
+
   def index
-    @active_personal_access_tokens = current_user.personal_access_tokens.active.order(:expires_at)
-    @inactive_personal_access_tokens = current_user.personal_access_tokens.inactive
     @personal_access_token = current_user.personal_access_tokens.build
   end
 
@@ -12,6 +12,7 @@ class Profiles::PersonalAccessTokensController < Profiles::ApplicationController
       flash[:personal_access_token] = @personal_access_token.token
       redirect_to profile_personal_access_tokens_path
     else
+      load_personal_access_tokens
       render :index
     end
   end
@@ -22,7 +23,7 @@ class Profiles::PersonalAccessTokensController < Profiles::ApplicationController
     if @personal_access_token.revoke!
       redirect_to profile_personal_access_tokens_path, notice: "Revoked personal access token #{@personal_access_token.name}!"
     else
-      render :index
+      redirect_to profile_personal_access_tokens_path, alert: "Could not revoke personal access token #{@personal_access_token.name}."
     end
   end
 
@@ -31,4 +32,9 @@ class Profiles::PersonalAccessTokensController < Profiles::ApplicationController
   def personal_access_token_params
     params.require(:personal_access_token).permit(:name, :expires_at)
   end
+
+  def load_personal_access_tokens
+    @active_personal_access_tokens = current_user.personal_access_tokens.active.order(:expires_at)
+    @inactive_personal_access_tokens = current_user.personal_access_tokens.inactive
+  end
 end

app/views/profiles/personal_access_tokens/index.html.haml

@@ -24,6 +24,8 @@
     = form_for [:profile, @personal_access_token],
                 method: :post, html: { class: 'js-requires-input' } do |f|
 
+      = form_errors(@personal_access_token)
+
       .form-group
         = f.label :name, class: 'label-light'
         = f.text_field :name, class: "form-control", required: true