Redacts quick actions used by support bot

Quick actions used by support bot via emails are
now enclosed within code span markdown instead of erased.

ee/changelogs/unreleased/issue_119433.yml

+---
+title: Redacts quick actions used by support bot
+merge_request: 23353
+author:
+type: changed

ee/lib/ee/gitlab/email/handler/reply_processing.rb

@@ -17,7 +17,7 @@ module EE
             command_definitions = ::QuickActions::InterpretService.command_definitions
             extractor = ::Gitlab::QuickActions::Extractor.new(command_definitions)
 
-            extractor.extract_commands(content)[0]
+            extractor.redact_commands(content)
           end
 
           override :process_message

ee/spec/fixtures/emails/service_desk_forwarded.eml

@@ -24,3 +24,7 @@ Service desk stuff!
 ```
 a = b
 ```
+
+/label ~label1
+/assign @user1
+/close

ee/spec/fixtures/emails/service_desk_legacy.eml

@@ -22,3 +22,7 @@ Service desk stuff!
 ```
 a = b
 ```
+
+/label ~label1
+/assign @user1
+/close

ee/spec/lib/gitlab/email/handler/create_note_handler_spec.rb

@@ -153,12 +153,12 @@ describe Gitlab::Email::Handler::CreateNoteHandler do
         end
 
         context 'when quick actions are present' do
-          it 'strips quick actions from email' do
+          it 'encloses quick actions with code span markdown' do
             receiver.execute
             noteable.reload
 
-            expect(note.note).not_to include('/close')
-            expect(note.note).not_to include('/title')
+            note = Note.last
+            expect(note.note).to include("Jake out\n\n`/close`\n`/title test`")
             expect(noteable.title).to eq('service desk issue')
             expect(noteable).to be_opened
           end

ee/spec/lib/gitlab/email/handler/ee/service_desk_handler_spec.rb

@@ -12,7 +12,9 @@ describe Gitlab::Email::Handler::EE::ServiceDeskHandler do
 
   let(:email_raw) { email_fixture('emails/service_desk.eml', dir: 'ee') }
   let_it_be(:namespace) { create(:namespace, name: "email") }
-  let(:expected_description) { "Service desk stuff!\n\n```\na = b\n```\n\n![image](uploads/image.png)" }
+  let(:expected_description) do
+    "Service desk stuff!\n\n```\na = b\n```\n\n`/label ~label1`\n`/assign @user1`\n`/close`\n![image](uploads/image.png)"
+  end
 
   context 'service desk is enabled for the project' do
     let_it_be(:project) { create(:project, :repository, :public, namespace: namespace, path: 'test', service_desk_enabled: true) }
@@ -100,16 +102,16 @@ describe Gitlab::Email::Handler::EE::ServiceDeskHandler do
               expect(issue.milestone).to eq(milestone)
             end
 
-            it 'does not apply quick actions present on user email body' do
+            it 'redacts quick actions present on user email body' do
               set_template_file('service_desk1', 'text from template')
 
               receiver.execute
 
               issue = Issue.last
               expect(issue).to be_opened
-              expect(issue.description).not_to include('/label ~label1')
-              expect(issue.description).not_to include('/assign @user1')
-              expect(issue.description).not_to include('/close')
+              expect(issue.description).to include('`/label ~label1`')
+              expect(issue.description).to include('`/assign @user1`')
+              expect(issue.description).to include('`/close`')
               expect(issue.assignees).to be_empty
               expect(issue.milestone).to be_nil
             end

lib/gitlab/quick_actions/extractor.rb

@@ -34,26 +34,55 @@ module Gitlab
       def extract_commands(content, only: nil)
         return [content, []] unless content
 
-        content = content.dup
+        content, commands = perform_regex(content, only: only)
 
-        commands = []
+        perform_substitutions(content, commands)
+      end
 
+      # Encloses quick action commands into code span markdown
+      # avoiding them being executed, for example, when sent via email
+      # to GitLab service desk.
+      # Example: /label ~label1 becomes `/label ~label1`
+      def redact_commands(content)
+        return "" unless content
+
+        content, _ = perform_regex(content, redact: true)
+
+        content
+      end
+
+      private
+
+      def perform_regex(content, only: nil, redact: false)
+        commands = []
+        content = content.dup
         content.delete!("\r")
+
         content.gsub!(commands_regex(only: only)) do
-          if $~[:cmd]
-            commands << [$~[:cmd].downcase, $~[:arg]].reject(&:blank?)
-            ''
-          else
-            $~[0]
-          end
+          command, output = process_commands($~, redact)
+          commands << command
+          output
         end
 
-        content, commands = perform_substitutions(content, commands)
-
-        [content.rstrip, commands]
+        [content.rstrip, commands.reject(&:empty?)]
       end
 
-      private
+      def process_commands(matched_text, redact)
+        output = matched_text[0]
+        command = []
+
+        if matched_text[:cmd]
+          command = [matched_text[:cmd].downcase, matched_text[:arg]].reject(&:blank?)
+          output = ''
+
+          if redact
+            output = "`/#{matched_text[:cmd]}#{" " + matched_text[:arg] if matched_text[:arg]}`"
+            output += "\n" if matched_text[0].include?("\n")
+          end
+        end
+
+        [command, output]
+      end
 
       # Builds a regular expression to match known commands.
       # First match group captures the command name and

spec/lib/gitlab/quick_actions/extractor_spec.rb

@@ -294,4 +294,22 @@ describe Gitlab::QuickActions::Extractor do
       expect(msg).to eq expected_msg
     end
   end
+
+  describe '#redact_commands' do
+    using RSpec::Parameterized::TableSyntax
+
+    where(:text, :expected) do
+      "hello\n/labels ~label1 ~label2\nworld" | "hello\n`/labels ~label1 ~label2`\nworld"
+      "hello\n/open\n/labels ~label1\nworld"  | "hello\n`/open`\n`/labels ~label1`\nworld"
+      "hello\n/reopen\nworld"                 | "hello\n`/reopen`\nworld"
+      "/reopen\nworld"                        | "`/reopen`\nworld"
+      "hello\n/open"                          | "hello\n`/open`"
+    end
+
+    with_them do
+      it 'encloses quick actions with code span markdown' do
+        expect(extractor.redact_commands(text)).to eq(expected)
+      end
+    end
+  end
 end