2 files changed, 61 insertions, 0 deletions
diff --git a/rubocop/cop/graphql/resource_not_available_error.rb b/rubocop/cop/graphql/resource_not_available_error.rb
new file mode 100644
index 00000000000..d759e145008
--- /dev/null
+++ b/rubocop/cop/graphql/resource_not_available_error.rb
@@ -0,0 +1,47 @@
+# frozen_string_literal: true
+
+require_relative '../../node_pattern_helper'
+
+module RuboCop
+  module Cop
+    module Graphql
+      # Encourages the use of `raise_resource_not_available_error!` method
+      # instead of `raise Gitlab::Graphql::Errors::ResourceNotAvailable`.
+      #
+      # @example
+      #
+      #   # bad
+      #   raise Gitlab::Graphql::Errors::ResourceNotAvailable, 'message'
+      #
+      #   # good
+      #   raise_resource_not_available_error! 'message'
+      class ResourceNotAvailableError < Base
+        extend NodePatternHelper
+        extend AutoCorrector
+
+        MSG = 'Prefer using `raise_resource_not_available_error!` instead.'
+
+        EXCEPTION = 'Gitlab::Graphql::Errors::ResourceNotAvailable'
+
+        RESTRICT_ON_SEND = %i[raise].freeze
+
+        def_node_matcher :error, const_pattern(EXCEPTION)
+
+        def_node_matcher :raise_error, <<~PATTERN
+          (send nil? :raise #error $...)
+        PATTERN
+
+        def on_send(node)
+          raise_error(node) do |args|
+            add_offense(node) do |corrector|
+              replacement = +'raise_resource_not_available_error!'
+              replacement << " #{args.map(&:source).join(', ')}" if args.any?
+
+              corrector.replace(node, replacement)
+            end
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/rubocop/node_pattern_helper.rb b/rubocop/node_pattern_helper.rb
new file mode 100644
index 00000000000..ecd4560763c
--- /dev/null
+++ b/rubocop/node_pattern_helper.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+module RuboCop
+  module NodePatternHelper
+    # Returns a nested `(const ...)` node pattern for a full qualified +name+.
+    #
+    # @examples
+    #   const_pattern 'Foo::Bar' # => (const (const {nil? cbase} :Foo) :Bar)
+    #   const_pattern 'Foo::Bar', parent: ':Baz' # => (const (const :Baz :Foo) :Bar)
+    def const_pattern(name, parent: '{nil? cbase}')
+      name.split('::').inject(parent) { |memo, name_part| "(const #{memo} :#{name_part})" }
+    end
+  end
+end