Allow to use + symbol in filenames

changelogs/unreleased/allow_plus_sign_for_snippets.yml

+---
+title: Allow to use + symbol in filenames
+merge_request: 6644
+author: blackst0ne

lib/gitlab/regex.rb

@@ -61,11 +61,11 @@ module Gitlab
     end
 
     def file_name_regex
-      @file_name_regex ||= /\A[[[:alnum:]]_\-\.\@]*\z/.freeze
+      @file_name_regex ||= /\A[[[:alnum:]]_\-\.\@\+]*\z/.freeze
     end
 
     def file_name_regex_message
-      "can contain only letters, digits, '_', '-', '@' and '.'."
+      "can contain only letters, digits, '_', '-', '@', '+' and '.'."
     end
 
     def file_path_regex

spec/features/snippets/create_snippet_spec.rb

@@ -17,4 +17,18 @@ feature 'Create Snippet', feature: true do
     expect(page).to have_content('My Snippet Title')
     expect(page).to have_content('Hello World!')
   end
+
+  scenario 'Authenticated user creates a snippet with + in filename' do
+    fill_in 'personal_snippet_title', with: 'My Snippet Title'
+    page.within('.file-editor') do
+      find(:xpath, "//input[@id='personal_snippet_file_name']").set 'snippet+file+name'
+      find(:xpath, "//input[@id='personal_snippet_content']").set 'Hello World!'
+    end
+
+    click_button 'Create snippet'
+
+    expect(page).to have_content('My Snippet Title')
+    expect(page).to have_content('snippet+file+name')
+    expect(page).to have_content('Hello World!')
+  end
 end