Fastlane lane to add empty TargetAttributes to pbxproj.

gistfile1.txt

  # Adds empty TargetAttributes to pbxproj
  lane :fix_target_attributes do |opts|
    require 'xcodeproj'
    
    xcodeproj_path = opts[:xcodeproj] || File.join(File.dirname(__FILE__), '..', XCODEPROJ_FILE)
    UI.important("Fixing TargetAttributes in #{xcodeproj_path}")

    project = Xcodeproj::Project.open(xcodeproj_path)
    
    root_object = project.root_object
    attributes = root_object.attributes
    
    if attributes['TargetAttributes'].nil?
      UI.important("TargetAttributes dictionary is missing, adding an empty one")
      
      attributes['TargetAttributes'] = {}
      
      project.save
      UI.success("Successfully added empty TargetAttributes dictionary to project")
    else
      UI.message("TargetAttributes dictionary already exists in project")
    end
  end

This is a workaround for the tuist/fastlane issue here

You can put this in your Fastfile and call it before calling update_project_codesigning_settings. I didn't even need to add xcodeproj to the gemfile since fastlane already uses it.