Optimize define_variables for create_deploy_token to avoid unnecessary data loading

Summary

The create_deploy_token action in Projects::Settings::RepositoryController currently uses a before_action :define_variables callback that loads several variables that are not needed for creating deploy tokens. This causes unnecessary database queries and performance overhead.

Problem

The define_variables method initializes:

• @deploy_keys - DeployKeysPresenter
• Deploy token variables (needed ✓)
• tag_names - Repository tag names
• branch_names - Repository branch names
• Protected refs (branches and tags with access levels)
• remote_mirror - First or initialized remote mirror

However, the create_deploy_token action only needs the deploy token variables. All other variables are loaded unnecessarily, especially when the action returns JSON responses (which is the common case).

Current Code

before_action :define_variables, only: [:create_deploy_token]

def create_deploy_token
  result = Projects::DeployTokens::CreateService.new(@project, current_user, deploy_token_params).execute
  # ... handles result and responds with JSON or HTML
end

def define_variables
  @deploy_keys = DeployKeysPresenter.new(@project, current_user: current_user)
  define_deploy_token_variables
  tag_names
  branch_names
  define_protected_refs
  remote_mirror
end

Proposed Solution

Refactor to only load the variables actually needed by create_deploy_token:

1. Extract deploy token-specific variable initialization into a separate method
2. Update the before_action for create_deploy_token to only call the minimal required initialization
3. Keep define_variables for the show action which needs all variables

Benefits

• Reduced database queries for deploy token creation
• Improved performance, especially for API/JSON requests
• Clearer separation of concerns between different controller actions

Related

• Identified in MR !212444 (merged) review: !212444 (comment 2893579426)