brew/Library/Homebrew/cask/audit.rb

# typed: false
# frozen_string_literal: true

require "cask/denylist"
require "cask/download"
require "digest"
require "livecheck/livecheck"
require "utils/curl"
require "utils/git"
require "utils/shared_audits"

module Cask
  # Audit a cask for various problems.
  #
  # @api private
  class Audit
    extend T::Sig

    extend Predicable

    attr_reader :cask, :download

    attr_predicate :appcast?, :new_cask?, :strict?, :signing?, :online?, :token_conflicts?

    def initialize(cask, appcast: nil, download: nil, quarantine: nil,
                   token_conflicts: nil, online: nil, strict: nil, signing: nil,
                   new_cask: nil, only: [], except: [])

      # `new_cask` implies `online`, `token_conflicts`, `strict` and `signing`
      online = new_cask if online.nil?
      strict = new_cask if strict.nil?
      signing = new_cask if signing.nil?
      token_conflicts = new_cask if token_conflicts.nil?

      # `online` implies `appcast` and `download`
      appcast = online if appcast.nil?
      download = online if download.nil?

      # `signing` implies `download`
      download = signing if download.nil?

      @cask = cask
      @appcast = appcast
      @download = Download.new(cask, quarantine: quarantine) if download
      @online = online
      @strict = strict
      @signing = signing
      @new_cask = new_cask
      @token_conflicts = token_conflicts
      @only = only
      @except = except
    end

    def run!
      only_audits = @only
      except_audits = @except

      private_methods.map(&:to_s).grep(/^check_/).each do |audit_method_name|
        name = audit_method_name.delete_prefix("check_")
        next if !only_audits.empty? && only_audits&.exclude?(name)
        next if except_audits&.include?(name)

        send(audit_method_name)
      end

      self
    rescue => e
      odebug e, e.backtrace
      add_error "exception while auditing #{cask}: #{e.message}"
      self
    end

    def errors
      @errors ||= []
    end

    def warnings
      @warnings ||= []
    end

    sig { returns(T::Boolean) }
    def errors?
      errors.any?
    end

    sig { returns(T::Boolean) }
    def warnings?
      warnings.any?
    end

    sig { returns(T::Boolean) }
    def success?
      !(errors? || warnings?)
    end

    sig { params(message: T.nilable(String), location: T.nilable(String)).void }
    def add_error(message, location: nil)
      errors << ({ message: message, location: location })
    end

    sig { params(message: T.nilable(String), location: T.nilable(String)).void }
    def add_warning(message, location: nil)
      if strict?
        add_error message, location: location
      else
        warnings << ({ message: message, location: location })
      end
    end

    def result
      if errors?
        Formatter.error("failed")
      elsif warnings?
        Formatter.warning("warning")
      else
        Formatter.success("passed")
      end
    end

    sig { params(include_passed: T::Boolean, include_warnings: T::Boolean).returns(String) }
    def summary(include_passed: false, include_warnings: true)
      return if success? && !include_passed
      return if warnings? && !errors? && !include_warnings

      summary = ["audit for #{cask}: #{result}"]

      errors.each do |error|
        summary << " #{Formatter.error("-")} #{error[:message]}"
      end

      if include_warnings
        warnings.each do |warning|
          summary << " #{Formatter.warning("-")} #{warning[:message]}"
        end
      end

      summary.join("\n")
    end

    private

    sig { void }
    def check_untrusted_pkg
      odebug "Auditing pkg stanza: allow_untrusted"

      return if @cask.sourcefile_path.nil?

      tap = @cask.tap
      return if tap.nil?
      return if tap.user != "Homebrew"

      return if cask.artifacts.none? { |k| k.is_a?(Artifact::Pkg) && k.stanza_options.key?(:allow_untrusted) }

      add_error "allow_untrusted is not permitted in official Homebrew Cask taps"
    end

    sig { void }
    def check_stanza_requires_uninstall
      odebug "Auditing stanzas which require an uninstall"

      return if cask.artifacts.none? { |k| k.is_a?(Artifact::Pkg) || k.is_a?(Artifact::Installer) }
      return if cask.artifacts.any?(Artifact::Uninstall)

      add_error "installer and pkg stanzas require an uninstall stanza"
    end

    sig { void }
    def check_single_pre_postflight
      odebug "Auditing preflight and postflight stanzas"

      if cask.artifacts.count { |k| k.is_a?(Artifact::PreflightBlock) && k.directives.key?(:preflight) } > 1
        add_error "only a single preflight stanza is allowed"
      end

      count = cask.artifacts.count do |k|
        k.is_a?(Artifact::PostflightBlock) &&
          k.directives.key?(:postflight)
      end
      return unless count > 1

      add_error "only a single postflight stanza is allowed"
    end

    sig { void }
    def check_single_uninstall_zap
      odebug "Auditing single uninstall_* and zap stanzas"

      if cask.artifacts.count { |k| k.is_a?(Artifact::Uninstall) } > 1
        add_error "only a single uninstall stanza is allowed"
      end

      count = cask.artifacts.count do |k|
        k.is_a?(Artifact::PreflightBlock) &&
          k.directives.key?(:uninstall_preflight)
      end

      add_error "only a single uninstall_preflight stanza is allowed" if count > 1

      count = cask.artifacts.count do |k|
        k.is_a?(Artifact::PostflightBlock) &&
          k.directives.key?(:uninstall_postflight)
      end

      add_error "only a single uninstall_postflight stanza is allowed" if count > 1

      return unless cask.artifacts.count { |k| k.is_a?(Artifact::Zap) } > 1

      add_error "only a single zap stanza is allowed"
    end

    sig { void }
    def check_required_stanzas
      odebug "Auditing required stanzas"
      [:version, :sha256, :url, :homepage].each do |sym|
        add_error "a #{sym} stanza is required" unless cask.send(sym)
      end
      add_error "at least one name stanza is required" if cask.name.empty?
      # TODO: specific DSL knowledge should not be spread around in various files like this
      rejected_artifacts = [:uninstall, :zap]
      installable_artifacts = cask.artifacts.reject { |k| rejected_artifacts.include?(k) }
      add_error "at least one activatable artifact stanza is required" if installable_artifacts.empty?
    end

    sig { void }
    def check_description_present
      # Fonts seldom benefit from descriptions and requiring them disproportionately increases the maintenance burden
      return if cask.tap == "homebrew/cask-fonts"

      add_warning "Cask should have a description. Please add a `desc` stanza." if cask.desc.blank?
    end

    sig { void }
    def check_no_string_version_latest
      return unless cask.version

      odebug "Auditing version :latest does not appear as a string ('latest')"
      return unless cask.version.raw_version == "latest"

      add_error "you should use version :latest instead of version 'latest'"
    end

    sig { void }
    def check_sha256_no_check_if_latest
      return unless cask.sha256

      odebug "Auditing sha256 :no_check with version :latest"
      return unless cask.version.latest?
      return if cask.sha256 == :no_check

      add_error "you should use sha256 :no_check when version is :latest"
    end

    sig { void }
    def check_sha256_no_check_if_unversioned
      return unless cask.sha256
      return if cask.sha256 == :no_check

      add_error "Use `sha256 :no_check` when URL is unversioned." if cask.url&.unversioned?
    end

    sig { void }
    def check_sha256_actually_256
      return unless cask.sha256

      odebug "Auditing sha256 string is a legal SHA-256 digest"
      return unless cask.sha256.is_a?(Checksum)
      return if cask.sha256.length == 64 && cask.sha256[/^[0-9a-f]+$/i]

      add_error "sha256 string must be of 64 hexadecimal characters"
    end

    sig { void }
    def check_sha256_invalid
      return unless cask.sha256

      odebug "Auditing sha256 is not a known invalid value"
      empty_sha256 = "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
      return unless cask.sha256 == empty_sha256

      add_error "cannot use the sha256 for an empty string: #{empty_sha256}"
    end

    sig { void }
    def check_appcast_and_livecheck
      return unless cask.appcast

      if cask.livecheckable?
        add_error "Cask has a `livecheck`, the `appcast` should be removed."
      elsif new_cask?
        add_error "New casks should use a `livecheck` instead of an `appcast`."
      end
    end

    sig { void }
    def check_latest_with_appcast_or_livecheck
      return unless cask.version.latest?

      add_error "Casks with an `appcast` should not use `version :latest`." if cask.appcast
      add_error "Casks with a `livecheck` should not use `version :latest`." if cask.livecheckable?
    end

    sig { void }
    def check_latest_with_auto_updates
      return unless cask.version.latest?
      return unless cask.auto_updates

      add_error "Casks with `version :latest` should not use `auto_updates`."
    end

    LIVECHECK_REFERENCE_URL = "https://docs.brew.sh/Cask-Cookbook#stanza-livecheck"

    sig { params(livecheck_result: T::Boolean).void }
    def check_hosting_with_livecheck(livecheck_result: check_livecheck_version)
      return if cask.discontinued? || cask.version.latest?
      return if block_url_offline? || cask.appcast || cask.livecheckable?
      return if livecheck_result == :auto_detected

      add_livecheck = "please add a livecheck. See #{Formatter.url(LIVECHECK_REFERENCE_URL)}"

      case cask.url.to_s
      when %r{sourceforge.net/(\S+)}
        return unless online?

        add_error "Download is hosted on SourceForge, #{add_livecheck}"
      when %r{dl.devmate.com/(\S+)}
        add_error "Download is hosted on DevMate, #{add_livecheck}"
      when %r{rink.hockeyapp.net/(\S+)}
        add_error "Download is hosted on HockeyApp, #{add_livecheck}"
      end
    end

    SOURCEFORGE_OSDN_REFERENCE_URL = "https://docs.brew.sh/Cask-Cookbook#sourceforgeosdn-urls"

    sig { void }
    def check_download_url_format
      return unless cask.url

      odebug "Auditing URL format"
      if bad_sourceforge_url?
        add_error "SourceForge URL format incorrect. See #{Formatter.url(SOURCEFORGE_OSDN_REFERENCE_URL)}"
      elsif bad_osdn_url?
        add_error "OSDN URL format incorrect. See #{Formatter.url(SOURCEFORGE_OSDN_REFERENCE_URL)}"
      end
    end

    VERIFIED_URL_REFERENCE_URL = "https://docs.brew.sh/Cask-Cookbook#when-url-and-homepage-domains-differ-add-verified"

    sig { void }
    def check_unnecessary_verified
      return if block_url_offline?
      return unless verified_present?
      return unless url_match_homepage?
      return unless verified_matches_url?

      add_error "The URL's domain #{Formatter.url(domain)} matches the homepage domain " \
                "#{Formatter.url(homepage)}, the 'verified' parameter of the 'url' stanza is unnecessary. " \
                "See #{Formatter.url(VERIFIED_URL_REFERENCE_URL)}"
    end

    sig { void }
    def check_missing_verified
      return if block_url_offline?
      return if file_url?
      return if url_match_homepage?
      return if verified_present?

      add_error "The URL's domain #{Formatter.url(domain)} does not match the homepage domain " \
                "#{Formatter.url(homepage)}, a 'verified' parameter has to be added to the 'url' stanza. " \
                "See #{Formatter.url(VERIFIED_URL_REFERENCE_URL)}"
    end

    sig { void }
    def check_no_match
      return if block_url_offline?
      return unless verified_present?
      return if verified_matches_url?

      add_error "Verified URL #{Formatter.url(url_from_verified)} does not match URL " \
                "#{Formatter.url(strip_url_scheme(cask.url.to_s))}. " \
                "See #{Formatter.url(VERIFIED_URL_REFERENCE_URL)}"
    end

    sig { void }
    def check_generic_artifacts
      cask.artifacts.select { |a| a.is_a?(Artifact::Artifact) }.each do |artifact|
        unless artifact.target.absolute?
          add_error "target must be absolute path for #{artifact.class.english_name} #{artifact.source}"
        end
      end
    end

    sig { void }
    def check_languages
      @cask.languages.each do |language|
        Locale.parse(language)
      rescue Locale::ParserError
        add_error "Locale '#{language}' is invalid."
      end
    end

    sig { void }
    def check_token_conflicts
      return unless token_conflicts?
      return unless core_formula_names.include?(cask.token)

      add_warning "possible duplicate, cask token conflicts with Homebrew core formula: " \
                  "#{Formatter.url(core_formula_url)}"
    end

    sig { void }
    def check_token_valid
      add_error "cask token contains non-ascii characters" unless cask.token.ascii_only?
      add_error "cask token + should be replaced by -plus-" if cask.token.include? "+"
      add_error "cask token whitespace should be replaced by hyphens" if cask.token.include? " "
      add_error "cask token @ should be replaced by -at-" if cask.token.include? "@"
      add_error "cask token underscores should be replaced by hyphens" if cask.token.include? "_"
      add_error "cask token should not contain double hyphens" if cask.token.include? "--"

      if cask.token.match?(/[^a-z0-9\-]/)
        add_error "cask token should only contain lowercase alphanumeric characters and hyphens"
      end

      return if !cask.token.start_with?("-") && !cask.token.end_with?("-")

      add_error "cask token should not have leading or trailing hyphens"
    end

    sig { void }
    def check_token_bad_words
      return unless new_cask?

      token = cask.token

      add_error "cask token contains .app" if token.end_with? ".app"

      if /-(?<designation>alpha|beta|rc|release-candidate)$/ =~ cask.token &&
         cask.tap&.official? &&
         cask.tap != "homebrew/cask-versions"
        add_error "cask token contains version designation '#{designation}'"
      end

      add_warning "cask token mentions launcher" if token.end_with? "launcher"

      add_warning "cask token mentions desktop" if token.end_with? "desktop"

      add_warning "cask token mentions platform" if token.end_with? "mac", "osx", "macos"

      add_warning "cask token mentions architecture" if token.end_with? "x86", "32_bit", "x86_64", "64_bit"

      frameworks = %w[cocoa qt gtk wx java]
      return if frameworks.include?(token) || !token.end_with?(*frameworks)

      add_warning "cask token mentions framework"
    end

    sig { void }
    def check_download
      return if download.blank? || cask.url.blank?

      odebug "Auditing download"
      download.fetch
    rescue => e
      add_error "download not possible: #{e}"
    end

    sig { void }
    def check_signing
      return if !signing? || download.blank? || cask.url.blank?

      odebug "Auditing signing"
      artifacts = cask.artifacts.select { |k| k.is_a?(Artifact::Pkg) || k.is_a?(Artifact::App) }

      return if artifacts.empty?

      downloaded_path = download.fetch
      primary_container = UnpackStrategy.detect(downloaded_path, type: @cask.container&.type, merge_xattrs: true)

      return if primary_container.nil?

      Dir.mktmpdir do |tmpdir|
        tmpdir = Pathname(tmpdir)
        primary_container.extract_nestedly(to: tmpdir, basename: downloaded_path.basename, verbose: false)
        artifacts.each do |artifact|
          path = case artifact
          when Artifact::Moved
            tmpdir/artifact.source.basename
          when Artifact::Pkg
            artifact.path
          end
          next unless path.exist?

          result = system_command("codesign", args: ["--verify", path], print_stderr: false)

          next if result.success?

          message = "Signature verification failed:\n#{result.merged_output}\nmacOS on ARM requires applications " \
                    "to be signed. Please contact the upstream developer to let them know they should "

          message += if result.stderr.include?("not signed at all")
            "sign their app."
          else
            "fix the signature of their app."
          end

          add_warning message
        end
      end
    end

    sig { returns(T.nilable(T.any(T::Boolean, Symbol))) }
    def check_livecheck_version
      return unless appcast?

      referenced_cask, = Homebrew::Livecheck.resolve_livecheck_reference(cask)

      # Respect skip conditions for a referenced cask
      if referenced_cask
        skip_info = Homebrew::Livecheck::SkipConditions.referenced_skip_information(
          referenced_cask,
          Homebrew::Livecheck.cask_name(cask),
        )
      end

      # Respect cask skip conditions (e.g. discontinued, latest, unversioned)
      skip_info ||= Homebrew::Livecheck::SkipConditions.skip_information(cask)
      return :skip if skip_info.present?

      latest_version = Homebrew::Livecheck.latest_version(
        cask,
        referenced_formula_or_cask: referenced_cask,
      )&.fetch(:latest)
      if cask.version.to_s == latest_version.to_s
        if cask.appcast
          add_error "Version '#{latest_version}' was automatically detected by livecheck; " \
                    "the appcast should be removed."
        end

        return :auto_detected
      end

      return :appcast if cask.appcast && !cask.livecheckable?

      add_error "Version '#{cask.version}' differs from '#{latest_version}' retrieved by livecheck."

      false
    end

    sig { void }
    def check_appcast_contains_version
      return unless appcast?
      return if cask.appcast.to_s.empty?
      return if cask.appcast.must_contain == :no_check

      appcast_url = cask.appcast.to_s
      begin
        details = curl_http_content_headers_and_checksum(appcast_url, user_agent: HOMEBREW_USER_AGENT_FAKE_SAFARI)
        appcast_contents = details[:file]
      rescue
        add_error "appcast at URL '#{Formatter.url(appcast_url)}' offline or looping"
        return
      end

      version_stanza = cask.version.to_s
      adjusted_version_stanza = cask.appcast.must_contain.presence || version_stanza.match(/^[[:alnum:].]+/)[0]
      return if appcast_contents.blank?
      return if appcast_contents.include?(adjusted_version_stanza)

      add_error <<~EOS.chomp
        appcast at URL '#{Formatter.url(appcast_url)}' does not contain \
        the version number '#{adjusted_version_stanza}':
        #{appcast_contents}
      EOS
    end

    sig { void }
    def check_github_prerelease_version
      return if cask.tap == "homebrew/cask-versions"

      odebug "Auditing GitHub prerelease"
      user, repo = get_repo_data(%r{https?://github\.com/([^/]+)/([^/]+)/?.*}) if online?
      return if user.nil?

      tag = SharedAudits.github_tag_from_url(cask.url)
      tag ||= cask.version
      error = SharedAudits.github_release(user, repo, tag, cask: cask)
      add_error error if error
    end

    sig { void }
    def check_gitlab_prerelease_version
      return if cask.tap == "homebrew/cask-versions"

      user, repo = get_repo_data(%r{https?://gitlab\.com/([^/]+)/([^/]+)/?.*}) if online?
      return if user.nil?

      odebug "Auditing GitLab prerelease"

      tag = SharedAudits.gitlab_tag_from_url(cask.url)
      tag ||= cask.version
      error = SharedAudits.gitlab_release(user, repo, tag, cask: cask)
      add_error error if error
    end

    sig { void }
    def check_github_repository_archived
      user, repo = get_repo_data(%r{https?://github\.com/([^/]+)/([^/]+)/?.*}) if online?
      return if user.nil?

      odebug "Auditing GitHub repo archived"

      metadata = SharedAudits.github_repo_data(user, repo)
      return if metadata.nil?

      return unless metadata["archived"]

      message = "GitHub repo is archived"

      if cask.discontinued?
        add_warning message
      else
        add_error message
      end
    end

    sig { void }
    def check_gitlab_repository_archived
      user, repo = get_repo_data(%r{https?://gitlab\.com/([^/]+)/([^/]+)/?.*}) if online?
      return if user.nil?

      odebug "Auditing GitLab repo archived"

      metadata = SharedAudits.gitlab_repo_data(user, repo)
      return if metadata.nil?

      return unless metadata["archived"]

      message = "GitLab repo is archived"

      if cask.discontinued?
        add_warning message
      else
        add_error message
      end
    end

    sig { void }
    def check_github_repository
      return unless new_cask?

      user, repo = get_repo_data(%r{https?://github\.com/([^/]+)/([^/]+)/?.*})
      return if user.nil?

      odebug "Auditing GitHub repo"

      error = SharedAudits.github(user, repo)
      add_error error if error
    end

    sig { void }
    def check_gitlab_repository
      return unless new_cask?

      user, repo = get_repo_data(%r{https?://gitlab\.com/([^/]+)/([^/]+)/?.*})
      return if user.nil?

      odebug "Auditing GitLab repo"

      error = SharedAudits.gitlab(user, repo)
      add_error error if error
    end

    sig { void }
    def check_bitbucket_repository
      return unless new_cask?

      user, repo = get_repo_data(%r{https?://bitbucket\.org/([^/]+)/([^/]+)/?.*})
      return if user.nil?

      odebug "Auditing Bitbucket repo"

      error = SharedAudits.bitbucket(user, repo)
      add_error error if error
    end

    sig { void }
    def check_denylist
      return unless cask.tap
      return unless cask.tap.official?
      return unless (reason = Denylist.reason(cask.token))

      add_error "#{cask.token} is not allowed: #{reason}"
    end

    sig { void }
    def check_reverse_migration
      return unless new_cask?
      return unless cask.tap
      return unless cask.tap.official?
      return unless cask.tap.tap_migrations.key?(cask.token)

      add_error "#{cask.token} is listed in tap_migrations.json"
    end

    sig { void }
    def check_https_availability
      return unless download

      if cask.url && !cask.url.using
        validate_url_for_https_availability(cask.url, "binary URL", cask.token, cask.tap,
                                            user_agents: [cask.url.user_agent])
      end

      if cask.appcast && appcast?
        validate_url_for_https_availability(cask.appcast, "appcast URL", cask.token, cask.tap, check_content: true)
      end

      return unless cask.homepage

      validate_url_for_https_availability(cask.homepage, "homepage URL", cask.token, cask.tap,
                                          user_agents:   [:browser, :default],
                                          check_content: true,
                                          strict:        strict?)
    end

    # sig {
    #   params(url_to_check: T.any(String, URL), url_type: String, cask_token: String, tap: Tap,
    #          options: T.untyped).void
    # }
    def validate_url_for_https_availability(url_to_check, url_type, cask_token, tap, **options)
      problem = curl_check_http_content(url_to_check.to_s, url_type, **options)
      exception = tap&.audit_exception(:secure_connection_audit_skiplist, cask_token, url_to_check.to_s)

      if problem
        add_error problem unless exception
      elsif exception
        add_error "#{url_to_check} is in the secure connection audit skiplist but does not need to be skipped"
      end
    end

    sig { params(regex: T.any(String, Regexp)).returns(T.nilable(T::Array[String])) }
    def get_repo_data(regex)
      return unless online?

      _, user, repo = *regex.match(cask.url.to_s)
      _, user, repo = *regex.match(cask.homepage) unless user
      _, user, repo = *regex.match(cask.appcast.to_s) unless user
      return if !user || !repo

      repo.gsub!(/.git$/, "")

      [user, repo]
    end

    sig {
      params(regex: T.any(String, Regexp), valid_formats_array: T::Array[T.any(String, Regexp)]).returns(T::Boolean)
    }
    def bad_url_format?(regex, valid_formats_array)
      return false unless cask.url.to_s.match?(regex)

      valid_formats_array.none? { |format| cask.url.to_s =~ format }
    end

    sig { returns(T::Boolean) }
    def bad_sourceforge_url?
      bad_url_format?(/sourceforge/,
                      [
                        %r{\Ahttps://sourceforge\.net/projects/[^/]+/files/latest/download\Z},
                        %r{\Ahttps://downloads\.sourceforge\.net/(?!(project|sourceforge)/)},
                      ])
    end

    sig { returns(T::Boolean) }
    def bad_osdn_url?
      bad_url_format?(/osd/, [%r{\Ahttps?://([^/]+.)?dl\.osdn\.jp/}])
    end

    # sig { returns(String) }
    def homepage
      URI(cask.homepage.to_s).host
    end

    # sig { returns(String) }
    def domain
      URI(cask.url.to_s).host
    end

    sig { returns(T::Boolean) }
    def url_match_homepage?
      host = cask.url.to_s
      host_uri = URI(host)
      host = if host.match?(/:\d/) && host_uri.port != 80
        "#{host_uri.host}:#{host_uri.port}"
      else
        host_uri.host
      end
      home = homepage.downcase
      if (split_host = host.split(".")).length >= 3
        host = split_host[-2..].join(".")
      end
      if (split_home = homepage.split(".")).length >= 3
        home = split_home[-2..].join(".")
      end
      host == home
    end

    # sig { params(url: String).returns(String) }
    def strip_url_scheme(url)
      url.sub(%r{^[^:/]+://(www\.)?}, "")
    end

    # sig { returns(String) }
    def url_from_verified
      strip_url_scheme(cask.url.verified)
    end

    sig { returns(T::Boolean) }
    def verified_matches_url?
      url_domain, url_path = strip_url_scheme(cask.url.to_s).split("/", 2)
      verified_domain, verified_path = url_from_verified.split("/", 2)

      (url_domain == verified_domain || (verified_domain && url_domain&.end_with?(".#{verified_domain}"))) &&
        (!verified_path || url_path&.start_with?(verified_path))
    end

    sig { returns(T::Boolean) }
    def verified_present?
      cask.url.verified.present?
    end

    sig { returns(T::Boolean) }
    def file_url?
      URI(cask.url.to_s).scheme == "file"
    end

    sig { returns(T::Boolean) }
    def block_url_offline?
      return false if online?

      cask.url.from_block?
    end

    sig { returns(Tap) }
    def core_tap
      @core_tap ||= CoreTap.instance
    end

    # sig { returns(T::Array[String]) }
    def core_formula_names
      core_tap.formula_names
    end

    sig { returns(String) }
    def core_formula_url
      "#{core_tap.default_remote}/blob/HEAD/Formula/#{cask.token}.rb"
    end
  end
end