Maintenance: Prevent back porting of new __() methods from develop.

.coffeelint/rules/prevent_underscore_backport.coffee

@@ -0,0 +1,20 @@
+module.exports = class PreventUnderscoreBackport
+
+  rule:
+    name: 'prevent_underscore_backport'
+    level: 'error'
+    message: 'The method __(...) is not available in current stable'
+    description: '''
+      '''
+
+  constructor: ->
+    @callTokens = []
+
+  tokens: ['CALL_START']
+
+  lintToken: (token, tokenApi) ->
+    [type, tokenValue] = token
+
+    p = tokenApi.peek(-1)
+    if p[1] == '__'
+      return { }

.gitlab/ci/pre.yml

@@ -48,7 +48,7 @@ brakeman:
 coffeelint:
   <<: *template_pre
   script:
-    - coffeelint app/
+    - coffeelint --rules ./.coffeelint/rules/* app/
 
 bundle-audit:
   <<: *template_pre

.rubocop/cop/zammad/prevent_underscore_backport.rb

@@ -0,0 +1,17 @@
+# Copyright (C) 2012-2021 Zammad Foundation, http://zammad-foundation.org/
+
+module RuboCop
+  module Cop
+    module Zammad
+      class PreventUnderscroreBackport < Base
+        MSG = <<~ERROR_MESSAGE.freeze
+          The method __(...) is not available in current stable.
+        ERROR_MESSAGE
+
+        def on_send(node)
+          add_offense(node) if node.method_name.eql? :__
+        end
+      end
+    end
+  end
+end

.rubocop/rubocop_zammad.rb

@@ -10,3 +10,4 @@ require_relative 'cop/zammad/no_to_sym_on_string'
 require_relative 'cop/zammad/prefer_negated_if_over_unless'
 require_relative 'cop/zammad/update_copyright'
 require_relative 'cop/zammad/forbid_rand'
+require_relative 'cop/zammad/prevent_underscore_backport'

coffeelint.json

@@ -131,5 +131,8 @@
   },
   "transform_messes_up_line_numbers": {
     "level": "error"
+  },
+  "prevent_underscore_backport": {
+    "level": "error"
   }
 }