validator.rb

require 'active_support/core_ext/array'
require 'active_support/core_ext/string/inflections'

module Pod
  # Validates a Specification.
  #
  # Extends the Linter from the Core to add additional which require the
  # LocalPod and the Installer.
  #
  # In detail it checks that the file patterns defined by the user match
  # actually do match at least a file and that the Pod builds, by installing
  # it without integration and building the project with xcodebuild.
  #
  class Validator
    include Config::Mixin

    # The default version of Swift to use when linting pods
    #
    DEFAULT_SWIFT_VERSION = '4.0'.freeze

    # The valid platforms for linting
    #
    VALID_PLATFORMS = Platform.all.freeze

    # @return [Specification::Linter] the linter instance from CocoaPods
    #         Core.
    #
    attr_reader :linter

    # Initialize a new instance
    #
    # @param  [Specification, Pathname, String] spec_or_path
    #         the Specification or the path of the `podspec` file to lint.
    #
    # @param  [Array<String>] source_urls
    #         the Source URLs to use in creating a {Podfile}.
    #
    # @param  [Array<String>] platforms
    #         the platforms to lint.
    #
    def initialize(spec_or_path, source_urls, platforms = [])
      @use_frameworks = true
      @linter = Specification::Linter.new(spec_or_path)
      @source_urls = if @linter.spec && @linter.spec.dependencies.empty? && @linter.spec.recursive_subspecs.all? { |s| s.dependencies.empty? }
                       []
                     else
                       source_urls.map { |url| config.sources_manager.source_with_name_or_url(url) }.map(&:url)
                     end

      @platforms = platforms.map do |platform|
        result =  case platform.to_s.downcase
                  # Platform doesn't recognize 'macos' as being the same as 'osx' when initializing
                  when 'macos' then Platform.macos
                  else Platform.new(platform, nil)
                  end
        unless valid_platform?(result)
          raise Informative, "Unrecognized platform `#{platform}`. Valid platforms: #{VALID_PLATFORMS.join(', ')}"
        end
        result
      end
      @use_frameworks = true
    end

    #-------------------------------------------------------------------------#

    # @return [Specification] the specification to lint.
    #
    def spec
      @linter.spec
    end

    # @return [Pathname] the path of the `podspec` file where {#spec} is
    #         defined.
    #
    def file
      @linter.file
    end

    # Returns a list of platforms to lint for a given Specification
    #
    # @param [Specification] spec
    #         The specification to lint
    #
    # @return [Array<Platform>] platforms to lint for the given specification
    #
    def platforms_to_lint(spec)
      return spec.available_platforms if @platforms.empty?

      # Validate that the platforms specified are actually supported by the spec
      results = @platforms.map do |platform|
        matching_platform = spec.available_platforms.find { |p| p.name == platform.name }
        unless matching_platform
          raise Informative, "Platform `#{platform}` is not supported by specification `#{spec}`."
        end
        matching_platform
      end.uniq

      results
    end

    # @return [Sandbox::FileAccessor] the file accessor for the spec.
    #
    attr_accessor :file_accessor

    #-------------------------------------------------------------------------#

    # Lints the specification adding a {Result} for any
    # failed check to the {#results} list.
    #
    # @note   This method shows immediately which pod is being processed and
    #         overrides the printed line once the result is known.
    #
    # @return [Bool] whether the specification passed validation.
    #
    def validate
      @results = []

      # Replace default spec with a subspec if asked for
      a_spec = spec
      if spec && @only_subspec
        subspec_name = @only_subspec.start_with?(spec.root.name) ? @only_subspec : "#{spec.root.name}/#{@only_subspec}"
        a_spec = spec.subspec_by_name(subspec_name, true, true)
        @subspec_name = a_spec.name
      end

      UI.print " -> #{a_spec ? a_spec.name : file.basename}\r" unless config.silent?
      $stdout.flush

      perform_linting
      perform_extensive_analysis(a_spec) if a_spec && !quick

      UI.puts ' -> '.send(result_color) << (a_spec ? a_spec.to_s : file.basename.to_s)
      print_results
      validated?
    end

    # Prints the result of the validation to the user.
    #
    # @return [void]
    #
    def print_results
      UI.puts results_message
    end

    def results_message
      message = ''
      results.each do |result|
        if result.platforms == [:ios]
          platform_message = '[iOS] '
        elsif result.platforms == [:osx]
          platform_message = '[OSX] '
        elsif result.platforms == [:watchos]
          platform_message = '[watchOS] '
        elsif result.platforms == [:tvos]
          platform_message = '[tvOS] '
        end

        subspecs_message = ''
        if result.is_a?(Result)
          subspecs = result.subspecs.uniq
          if subspecs.count > 2
            subspecs_message = '[' + subspecs[0..2].join(', ') + ', and more...] '
          elsif subspecs.count > 0
            subspecs_message = '[' + subspecs.join(',') + '] '
          end
        end

        case result.type
        when :error   then type = 'ERROR'
        when :warning then type = 'WARN'
        when :note    then type = 'NOTE'
        else raise "#{result.type}" end
        message << "    - #{type.ljust(5)} | #{platform_message}#{subspecs_message}#{result.attribute_name}: #{result.message}\n"
      end
      message << "\n"
    end

    def failure_reason
      results_by_type = results.group_by(&:type)
      results_by_type.default = []
      return nil if validated?
      reasons = []
      if (size = results_by_type[:error].size) && size > 0
        reasons << "#{size} #{'error'.pluralize(size)}"
      end
      if !allow_warnings && (size = results_by_type[:warning].size) && size > 0
        reason = "#{size} #{'warning'.pluralize(size)}"
        pronoun = size == 1 ? 'it' : 'them'
        reason << " (but you can use `--allow-warnings` to ignore #{pronoun})" if reasons.empty?
        reasons << reason
      end
      if results.all?(&:public_only)
        reasons << 'all results apply only to public specs, but you can use ' \
                   '`--private` to ignore them if linting the specification for a private pod'
      end

      reasons.to_sentence
    end

    #-------------------------------------------------------------------------#

    #  @!group Configuration

    # @return [Bool] whether the validation should skip the checks that
    #         requires the download of the library.
    #
    attr_accessor :quick

    # @return [Bool] whether the linter should not clean up temporary files
    #         for inspection.
    #
    attr_accessor :no_clean

    # @return [Bool] whether the linter should fail as soon as the first build
    #         variant causes an error. Helpful for i.e. multi-platforms specs,
    #         specs with subspecs.
    #
    attr_accessor :fail_fast

    # @return [Bool] whether the validation should be performed against the root of
    #         the podspec instead to its original source.
    #
    # @note   Uses the `:path` option of the Podfile.
    #
    attr_accessor :local
    alias_method :local?, :local

    # @return [Bool] Whether the validator should fail on warnings, or only on errors.
    #
    attr_accessor :allow_warnings

    # @return [String] name of the subspec to check, if nil all subspecs are checked.
    #
    attr_accessor :only_subspec

    # @return [Bool] Whether the validator should validate all subspecs.
    #
    attr_accessor :no_subspecs

    # @return [Bool] Whether the validator should skip building and running tests.
    #
    attr_accessor :skip_tests

    # @return [Array<String>] List of test_specs to run. If nil, all tests are run (unless skip_tests is specified).
    #
    attr_accessor :test_specs

    # @return [Bool] Whether the validator should run Xcode Static Analysis.
    #
    attr_accessor :analyze

    # @return [Bool] Whether frameworks should be used for the installation.
    #
    attr_accessor :use_frameworks

    # @return [Boolean] Whether modular headers should be used for the installation.
    #
    attr_accessor :use_modular_headers

    # @return [Boolean] Whether static frameworks should be used for the installation.
    #
    attr_accessor :use_static_frameworks

    # @return [Boolean] Whether attributes that affect only public sources
    #         Bool be skipped.
    #
    attr_accessor :ignore_public_only_results

    # @return [String] A glob for podspecs to be used during building of
    #         the local Podfile via :path.
    #
    attr_accessor :include_podspecs

    # @return [String] A glob for podspecs to be used during building of
    #         the local Podfile via :podspec.
    #
    attr_accessor :external_podspecs

    attr_accessor :skip_import_validation
    alias_method :skip_import_validation?, :skip_import_validation

    #-------------------------------------------------------------------------#

    # !@group Lint results

    #
    #
    attr_reader :results

    # @return [Boolean]
    #
    def validated?
      result_type != :error && (result_type != :warning || allow_warnings)
    end

    # @return [Symbol] The type, which should been used to display the result.
    #         One of: `:error`, `:warning`, `:note`.
    #
    def result_type
      applicable_results = results
      applicable_results = applicable_results.reject(&:public_only?) if ignore_public_only_results
      types              = applicable_results.map(&:type).uniq
      if    types.include?(:error)   then :error
      elsif types.include?(:warning) then :warning
      else  :note
      end
    end

    # @return [Symbol] The color, which should been used to display the result.
    #         One of: `:green`, `:yellow`, `:red`.
    #
    def result_color
      case result_type
      when :error   then :red
      when :warning then :yellow
      else :green end
    end

    # @return [Pathname] the temporary directory used by the linter.
    #
    def validation_dir
      @validation_dir ||= Pathname(Dir.mktmpdir(['CocoaPods-Lint-', "-#{spec.name}"]))
    end

    # @return [String] The SWIFT_VERSION that should be used to validate the pod. This is set by passing the
    # `--swift-version` parameter during validation.
    #
    attr_accessor :swift_version

    # @return [String] the SWIFT_VERSION within the .swift-version file or nil.
    #
    def dot_swift_version
      return unless file
      swift_version_path = file.dirname + '.swift-version'
      return unless swift_version_path.exist?
      swift_version_path.read.strip
    end

    # @return [String] The derived Swift version to use for validation. The order of precedence is as follows:
    #         - The `--swift-version` parameter is always checked first and honored if passed.
    #         - The `swift_versions` DSL attribute within the podspec, in which case the latest version is always chosen.
    #         - The Swift version within the `.swift-version` file if present.
    #         - If none of the above are set then the `#DEFAULT_SWIFT_VERSION` is used.
    #
    def derived_swift_version
      @derived_swift_version ||= begin
        if !swift_version.nil?
          swift_version
        elsif version = spec.swift_versions.max || dot_swift_version
          version.to_s
        else
          DEFAULT_SWIFT_VERSION
        end
      end
    end

    # @return [Boolean] Whether any of the pod targets part of this validator use Swift or not.
    #
    def uses_swift?
      @installer.pod_targets.any?(&:uses_swift?)
    end

    #-------------------------------------------------------------------------#

    private

    # !@group Lint steps

    #
    #
    def perform_linting
      linter.lint
      @results.concat(linter.results.to_a)
    end

    # Perform analysis for a given spec (or subspec)
    #
    def perform_extensive_analysis(spec)
      if spec.non_library_specification?
        error('spec', "Validating a non library spec (`#{spec.name}`) is not supported.")
        return false
      end
      validate_homepage(spec)
      validate_screenshots(spec)
      validate_social_media_url(spec)
      validate_documentation_url(spec)
      validate_source_url(spec)

      platforms = platforms_to_lint(spec)

      valid = platforms.send(fail_fast ? :all? : :each) do |platform|
        UI.message "\n\n#{spec} - Analyzing on #{platform} platform.".green.reversed
        @consumer = spec.consumer(platform)
        setup_validation_environment
        begin
          create_app_project
          download_pod
          check_file_patterns
          install_pod
          validate_swift_version
          add_app_project_import
          validate_vendored_dynamic_frameworks
          build_pod
          test_pod unless skip_tests
        ensure
          tear_down_validation_environment
        end
        validated?
      end
      return false if fail_fast && !valid
      perform_extensive_subspec_analysis(spec) unless @no_subspecs
    rescue => e
      message = e.to_s
      message << "\n" << e.backtrace.join("\n") << "\n" if config.verbose?
      error('unknown', "Encountered an unknown error (#{message}) during validation.")
      false
    end

    # Recursively perform the extensive analysis on all subspecs
    #
    def perform_extensive_subspec_analysis(spec)
      spec.subspecs.reject(&:non_library_specification?).send(fail_fast ? :all? : :each) do |subspec|
        @subspec_name = subspec.name
        perform_extensive_analysis(subspec)
      end
    end

    # @return [Consumer] the consumer for the current platform being validated
    #
    attr_accessor :consumer

    # @return [String, Nil] the name of the current subspec being validated, or nil if none
    #
    attr_accessor :subspec_name

    # Performs validation of a URL
    #
    def validate_url(url, user_agent = nil)
      resp = Pod::HTTP.validate_url(url, user_agent)

      if !resp
        warning('url', "There was a problem validating the URL #{url}.", true)
      elsif !resp.success?
        warning('url', "The URL (#{url}) is not reachable.", true)
      end

      resp
    end

    # Performs validations related to the `homepage` attribute.
    #
    def validate_homepage(spec)
      if spec.homepage
        validate_url(spec.homepage)
      end
    end

    # Performs validation related to the `screenshots` attribute.
    #
    def validate_screenshots(spec)
      spec.screenshots.compact.each do |screenshot|
        response = validate_url(screenshot)
        if response && !(response.headers['content-type'] && response.headers['content-type'].first =~ /image\/.*/i)
          warning('screenshot', "The screenshot #{screenshot} is not a valid image.")
        end
      end
    end

    # Performs validations related to the `social_media_url` attribute.
    #
    def validate_social_media_url(spec)
      validate_url(spec.social_media_url, 'CocoaPods') if spec.social_media_url
    end

    # Performs validations related to the `documentation_url` attribute.
    #
    def validate_documentation_url(spec)
      validate_url(spec.documentation_url) if spec.documentation_url
    end

    # Performs validations related to the `source` -> `http` attribute (if exists)
    #
    def validate_source_url(spec)
      return if spec.source.nil? || spec.source[:http].nil?
      url = URI(spec.source[:http])
      return if url.scheme == 'https' || url.scheme == 'file'
      warning('http', "The URL (`#{url}`) doesn't use the encrypted HTTPS protocol. " \
              'It is crucial for Pods to be transferred over a secure protocol to protect your users from man-in-the-middle attacks. '\
              'This will be an error in future releases. Please update the URL to use https.')
    end

    # Performs validation for the version of Swift used during validation.
    #
    # An error will be displayed if the user has provided a `swift_versions` attribute within the podspec but is also
    # using either `--swift-version` parameter or a `.swift-version` file with a Swift version that is not declared
    # within the attribute.
    #
    # The user will be warned that the default version of Swift was used if the following things are true:
    #   - The project uses Swift at all
    #   - The user did not supply a Swift version via a parameter
    #   - There is no `swift_versions` attribute set within the specification
    #   - There is no `.swift-version` file present either.
    #
    def validate_swift_version
      return unless uses_swift?
      spec_swift_versions = spec.swift_versions.map(&:to_s)

      unless spec_swift_versions.empty?
        message = nil
        if !dot_swift_version.nil? && !spec_swift_versions.include?(dot_swift_version)
          message = "Specification `#{spec.name}` specifies inconsistent `swift_versions` (#{spec_swift_versions.map { |s| "`#{s}`" }.to_sentence}) compared to the one present in your `.swift-version` file (`#{dot_swift_version}`). " \
                    'Please remove the `.swift-version` file which is now deprecated and only use the `swift_versions` attribute within your podspec.'
        elsif !swift_version.nil? && !spec_swift_versions.include?(swift_version)
          message = "Specification `#{spec.name}` specifies inconsistent `swift_versions` (#{spec_swift_versions.map { |s| "`#{s}`" }.to_sentence}) compared to the one passed during lint (`#{swift_version}`)."
        end
        unless message.nil?
          error('swift', message)
          return
        end
      end

      if swift_version.nil? && spec.swift_versions.empty?
        if !dot_swift_version.nil?
          # The user will be warned to delete the `.swift-version` file in favor of the `swift_versions` DSL attribute.
          # This is intentionally not a lint warning since we do not want to break existing setups and instead just soft
          # deprecate this slowly.
          #
          UI.warn 'Usage of the `.swift_version` file has been deprecated! Please delete the file and use the ' \
            "`swift_versions` attribute within your podspec instead.\n".yellow
        else
          warning('swift',
                  'The validator used ' \
                  "Swift `#{DEFAULT_SWIFT_VERSION}` by default because no Swift version was specified. " \
                  'To specify a Swift version during validation, add the `swift_versions` attribute in your podspec. ' \
                  'Note that usage of a `.swift-version` file is now deprecated.')
        end
      end
    end

    def setup_validation_environment
      validation_dir.rmtree if validation_dir.exist?
      validation_dir.mkpath
      @original_config = Config.instance.clone
      config.installation_root   = validation_dir
      config.silent              = !config.verbose
    end

    def tear_down_validation_environment
      clean! unless no_clean
      Config.instance = @original_config
    end

    def clean!
      validation_dir.rmtree
    end

    def deployment_target
      deployment_target = spec.subspec_by_name(subspec_name).deployment_target(consumer.platform_name)
      if consumer.platform_name == :ios && use_frameworks
        minimum = Version.new('8.0')
        deployment_target = [Version.new(deployment_target), minimum].max.to_s
      end
      deployment_target
    end

    def download_pod
      test_spec_names = consumer.spec.test_specs.select { |ts| ts.supported_on_platform?(consumer.platform_name) }.map(&:name)
      podfile = podfile_from_spec(consumer.platform_name, deployment_target, use_frameworks, test_spec_names, use_modular_headers, use_static_frameworks)
      sandbox = Sandbox.new(config.sandbox_root)
      @installer = Installer.new(sandbox, podfile)
      @installer.use_default_plugins = false
      @installer.has_dependencies = !spec.dependencies.empty?
      %i(prepare resolve_dependencies download_dependencies write_lockfiles).each { |m| @installer.send(m) }
      @file_accessor = @installer.pod_targets.flat_map(&:file_accessors).find { |fa| fa.spec.name == consumer.spec.name }
    end

    def create_app_project
      app_project = Xcodeproj::Project.new(validation_dir + 'App.xcodeproj')
      app_target = Pod::Generator::AppTargetHelper.add_app_target(app_project, consumer.platform_name, deployment_target)
      Pod::Generator::AppTargetHelper.add_swift_version(app_target, derived_swift_version)
      # Lint will fail if a AppIcon is set but no image is found with such name
      # Happens only with Static Frameworks enabled but shouldn't be set anyway
      app_target.build_configurations.each do |config|
        config.build_settings.delete('ASSETCATALOG_COMPILER_APPICON_NAME')
      end
      app_project.save
      app_project.recreate_user_schemes
    end

    def add_app_project_import
      app_project = Xcodeproj::Project.open(validation_dir + 'App.xcodeproj')
      app_target = app_project.targets.first
      pod_target = validation_pod_target
      Pod::Generator::AppTargetHelper.add_app_project_import(app_project, app_target, pod_target, consumer.platform_name)
      Pod::Generator::AppTargetHelper.add_xctest_search_paths(app_target) if @installer.pod_targets.any? { |pt| pt.spec_consumers.any? { |c| c.frameworks.include?('XCTest') || c.weak_frameworks.include?('XCTest') } }
      Pod::Generator::AppTargetHelper.add_empty_swift_file(app_project, app_target) if @installer.pod_targets.any?(&:uses_swift?)
      app_project.save
      Xcodeproj::XCScheme.share_scheme(app_project.path, 'App')
      # Share the pods xcscheme only if it exists. For pre-built vendored pods there is no xcscheme generated.
      Xcodeproj::XCScheme.share_scheme(@installer.pods_project.path, pod_target.label) if shares_pod_target_xcscheme?(pod_target)
    end

    # Returns the pod target for the pod being validated. Installation must have occurred before this can be invoked.
    #
    def validation_pod_target
      @installer.pod_targets.find { |pt| pt.pod_name == spec.root.name }
    end

    # It creates a podfile in memory and builds a library containing the pod
    # for all available platforms with xcodebuild.
    #
    def install_pod
      %i(validate_targets generate_pods_project integrate_user_project
         perform_post_install_actions).each { |m| @installer.send(m) }

      deployment_target = spec.subspec_by_name(subspec_name).deployment_target(consumer.platform_name)
      configure_pod_targets(@installer.target_installation_results)
      validate_dynamic_framework_support(@installer.aggregate_targets, deployment_target)
      @installer.pods_project.save
    end

    # @param [Array<Hash{String, TargetInstallationResult}>] target_installation_results
    #        The installation results to configure
    #
    def configure_pod_targets(target_installation_results)
      target_installation_results.first.values.each do |pod_target_installation_result|
        pod_target = pod_target_installation_result.target
        native_target = pod_target_installation_result.native_target
        native_target.build_configuration_list.build_configurations.each do |build_configuration|
          (build_configuration.build_settings['OTHER_CFLAGS'] ||= '$(inherited)') << ' -Wincomplete-umbrella'
          if pod_target.uses_swift?
            # The Swift version for the target being validated can be overridden by `--swift-version` or the
            # `.swift-version` file so we always use the derived Swift version.
            #
            # For dependencies, if the derived Swift version is supported then it is the one used. Otherwise, the Swift
            # version for dependencies is inferred by the target that is integrating them.
            swift_version = if pod_target == validation_pod_target
                              derived_swift_version
                            else
                              pod_target.spec_swift_versions.map(&:to_s).find do |v|
                                v == derived_swift_version
                              end || pod_target.swift_version
                            end
            build_configuration.build_settings['SWIFT_VERSION'] = swift_version
          end
        end
        pod_target_installation_result.test_specs_by_native_target.each do |test_native_target, test_spec|
          if pod_target.uses_swift_for_spec?(test_spec)
            test_native_target.build_configuration_list.build_configurations.each do |build_configuration|
              swift_version = pod_target == validation_pod_target ? derived_swift_version : pod_target.swift_version
              build_configuration.build_settings['SWIFT_VERSION'] = swift_version
            end
          end
        end
      end
    end

    # Produces an error of dynamic frameworks were requested but are not supported by the deployment target
    #
    # @param [Array<AggregateTarget>] aggregate_targets
    #        The aggregate targets installed by the installer
    #
    # @param [String,Version] deployment_target
    #        The deployment target of the installation
    #
    def validate_dynamic_framework_support(aggregate_targets, deployment_target)
      return unless consumer.platform_name == :ios
      return unless deployment_target.nil? || Version.new(deployment_target).major < 8
      aggregate_targets.each do |target|
        if target.pod_targets.any?(&:uses_swift?)
          uses_xctest = target.spec_consumers.any? { |c| (c.frameworks + c.weak_frameworks).include? 'XCTest' }
          error('swift', 'Swift support uses dynamic frameworks and is therefore only supported on iOS > 8.') unless uses_xctest
        end
      end
    end

    def validate_vendored_dynamic_frameworks
      deployment_target = spec.subspec_by_name(subspec_name).deployment_target(consumer.platform_name)

      unless file_accessor.nil?
        dynamic_frameworks = file_accessor.vendored_dynamic_frameworks
        dynamic_libraries = file_accessor.vendored_dynamic_libraries
        if (dynamic_frameworks.count > 0 || dynamic_libraries.count > 0) && consumer.platform_name == :ios &&
            (deployment_target.nil? || Version.new(deployment_target).major < 8)
          error('dynamic', 'Dynamic frameworks and libraries are only supported on iOS 8.0 and onwards.')
        end
      end
    end

    # Performs platform specific analysis. It requires to download the source
    # at each iteration
    #
    # @note   Xcode warnings are treated as notes because the spec maintainer
    #         might not be the author of the library
    #
    # @return [void]
    #
    def build_pod
      if !xcodebuild_available?
        UI.warn "Skipping compilation with `xcodebuild` because it can't be found.\n".yellow
      else
        UI.message "\nBuilding with `xcodebuild`.\n".yellow do
          scheme = if skip_import_validation?
                     validation_pod_target.label if validation_pod_target.should_build?
                   else
                     'App'
                   end
          if scheme.nil?
            UI.warn "Skipping compilation with `xcodebuild` because target contains no sources.\n".yellow
          else
            if analyze
              output = xcodebuild('analyze', scheme, 'Release')
              find_output = Executable.execute_command('find', [validation_dir, '-name', '*.html'], false)
              if find_output != ''
                message = 'Static Analysis failed.'
                message += ' You can use `--verbose` for more information.' unless config.verbose?
                message += ' You can use `--no-clean` to save a reproducible buid environment.' unless no_clean
                error('build_pod', message)
              end
            else
              output = xcodebuild('build', scheme, 'Release')
            end
            parsed_output = parse_xcodebuild_output(output)
            translate_output_to_linter_messages(parsed_output)
          end
        end
      end
    end

    # Builds and runs all test sources associated with the current specification being validated.
    #
    # @note   Xcode warnings are treated as notes because the spec maintainer
    #         might not be the author of the library
    #
    # @return [void]
    #
    def test_pod
      if !xcodebuild_available?
        UI.warn "Skipping test validation with `xcodebuild` because it can't be found.\n".yellow
      else
        UI.message "\nTesting with `xcodebuild`.\n".yellow do
          pod_target = validation_pod_target
          all_test_specs = consumer.spec.test_specs
          unless test_specs.nil?
            test_spec_names = all_test_specs.map(&:base_name)
            all_test_specs.select! { |test_spec| test_specs.include? test_spec.base_name }
            test_specs.each do |test_spec|
              unless test_spec_names.include? test_spec
                UI.warn "Requested test spec `#{test_spec}` does not exist in the podspec. Existing test specs are `#{test_spec_names}`"
              end
            end
          end
          all_test_specs.each do |test_spec|
            if !test_spec.supported_on_platform?(consumer.platform_name)
              UI.warn "Skipping test spec `#{test_spec.name}` on platform `#{consumer.platform_name}` since it is not supported.\n".yellow
            else
              scheme = @installer.target_installation_results.first[pod_target.name].native_target_for_spec(test_spec)
              output = xcodebuild('test', scheme, 'Debug')
              parsed_output = parse_xcodebuild_output(output)
              translate_output_to_linter_messages(parsed_output)
            end
          end
        end
      end
    end

    def xcodebuild_available?
      !Executable.which('xcodebuild').nil? && ENV['COCOAPODS_VALIDATOR_SKIP_XCODEBUILD'].nil?
    end

    FILE_PATTERNS = %i(source_files resources preserve_paths vendored_libraries
                       vendored_frameworks public_header_files preserve_paths
                       private_header_files resource_bundles).freeze

    # It checks that every file pattern specified in a spec yields
    # at least one file. It requires the pods to be already present
    # in the current working directory under Pods/spec.name.
    #
    # @return [void]
    #
    def check_file_patterns
      FILE_PATTERNS.each do |attr_name|
        if respond_to?("_validate_#{attr_name}", true)
          send("_validate_#{attr_name}")
        else
          validate_nonempty_patterns(attr_name, :error)
        end
      end

      _validate_header_mappings_dir
      if consumer.spec.root?
        _validate_license
        _validate_module_map
      end
    end

    # Validates that the file patterns in `attr_name` match at least 1 file.
    #
    # @param [String,Symbol] attr_name the name of the attribute to check (ex. :public_header_files)
    #
    # @param [String,Symbol] message_type the type of message to send if the patterns are empty (ex. :error)
    #
    def validate_nonempty_patterns(attr_name, message_type)
      return unless !file_accessor.spec_consumer.send(attr_name).empty? && file_accessor.send(attr_name).empty?

      add_result(message_type, 'file patterns', "The `#{attr_name}` pattern did not match any file.")
    end

    def _validate_private_header_files
      _validate_header_files(:private_header_files)
      validate_nonempty_patterns(:private_header_files, :warning)
    end

    def _validate_public_header_files
      _validate_header_files(:public_header_files)
      validate_nonempty_patterns(:public_header_files, :warning)
    end

    def _validate_license
      unless file_accessor.license || spec.license && (spec.license[:type] == 'Public Domain' || spec.license[:text])
        warning('license', 'Unable to find a license file')
      end
    end

    def _validate_module_map
      if spec.module_map
        unless file_accessor.module_map.exist?
          error('module_map', 'Unable to find the specified module map file.')
        end
        unless file_accessor.module_map.extname == '.modulemap'
          relative_path = file_accessor.module_map.relative_path_from file_accessor.root
          error('module_map', "Unexpected file extension for modulemap file (#{relative_path}).")
        end
      end
    end

    def _validate_resource_bundles
      file_accessor.resource_bundles.each do |bundle, resource_paths|
        next unless resource_paths.empty?
        error('file patterns', "The `resource_bundles` pattern for `#{bundle}` did not match any file.")
      end
    end

    # Ensures that a list of header files only contains header files.
    #
    def _validate_header_files(attr_name)
      header_files = file_accessor.send(attr_name)
      non_header_files = header_files.
        select { |f| !Sandbox::FileAccessor::HEADER_EXTENSIONS.include?(f.extname) }.
        map { |f| f.relative_path_from(file_accessor.root) }
      unless non_header_files.empty?
        error(attr_name, "The pattern matches non-header files (#{non_header_files.join(', ')}).")
      end
      non_source_files = header_files - file_accessor.source_files
      unless non_source_files.empty?
        error(attr_name, 'The pattern includes header files that are not listed ' \
          "in source_files (#{non_source_files.join(', ')}).")
      end
    end

    def _validate_header_mappings_dir
      return unless header_mappings_dir = file_accessor.spec_consumer.header_mappings_dir
      absolute_mappings_dir = file_accessor.root + header_mappings_dir
      unless absolute_mappings_dir.directory?
        error('header_mappings_dir', "The header_mappings_dir (`#{header_mappings_dir}`) is not a directory.")
      end
      non_mapped_headers = file_accessor.headers.
        reject { |h| h.to_path.start_with?(absolute_mappings_dir.to_path) }.
        map { |f| f.relative_path_from(file_accessor.root) }
      unless non_mapped_headers.empty?
        error('header_mappings_dir', "There are header files outside of the header_mappings_dir (#{non_mapped_headers.join(', ')}).")
      end
    end

    #-------------------------------------------------------------------------#

    private

    # !@group Result Helpers

    def error(*args)
      add_result(:error, *args)
    end

    def warning(*args)
      add_result(:warning, *args)
    end

    def note(*args)
      add_result(:note, *args)
    end

    def translate_output_to_linter_messages(parsed_output)
      parsed_output.each do |message|
        # Checking the error for `InputFile` is to work around an Xcode
        # issue where linting would fail even though `xcodebuild` actually
        # succeeds. Xcode.app also doesn't fail when this issue occurs, so
        # it's safe for us to do the same.
        #
        # For more details see https://github.com/CocoaPods/CocoaPods/issues/2394#issuecomment-56658587
        #
        if message.include?("'InputFile' should have")
          next
        end

        if message =~ /\S+:\d+:\d+: error:/
          error('xcodebuild', message)
        elsif message =~ /\S+:\d+:\d+: warning:/
          warning('xcodebuild', message)
        else
          note('xcodebuild', message)
        end
      end
    end

    def shares_pod_target_xcscheme?(pod_target)
      Pathname.new(@installer.pods_project.path + pod_target.label).exist?
    end

    def add_result(type, attribute_name, message, public_only = false)
      result = results.find do |r|
        r.type == type && r.attribute_name && r.message == message && r.public_only? == public_only
      end
      unless result
        result = Result.new(type, attribute_name, message, public_only)
        results << result
      end
      result.platforms << consumer.platform_name if consumer
      result.subspecs << subspec_name if subspec_name && !result.subspecs.include?(subspec_name)
    end

    # Specialized Result to support subspecs aggregation
    #
    class Result < Specification::Linter::Results::Result
      def initialize(type, attribute_name, message, public_only = false)
        super(type, attribute_name, message, public_only)
        @subspecs = []
      end

      attr_reader :subspecs
    end

    #-------------------------------------------------------------------------#

    private

    # !@group Helpers

    # @return [Array<String>] an array of source URLs used to create the
    #         {Podfile} used in the linting process
    #
    attr_reader :source_urls

    # @param  [String] platform_name
    #         the name of the platform, which should be declared
    #         in the Podfile.
    #
    # @param  [String] deployment_target
    #         the deployment target, which should be declared in
    #         the Podfile.
    #
    # @param  [Bool] use_frameworks
    #         whether frameworks should be used for the installation
    #
    # @param [Array<String>] test_spec_names
    #         the test spec names to include in the podfile.
    #
    # @return [Podfile] a podfile that requires the specification on the
    #         current platform.
    #
    # @note   The generated podfile takes into account whether the linter is
    #         in local mode.
    #
    def podfile_from_spec(platform_name, deployment_target, use_frameworks = true, test_spec_names = [], use_modular_headers = false, use_static_frameworks = false)
      name     = subspec_name || spec.name
      podspec  = file.realpath
      local    = local?
      urls     = source_urls

      additional_podspec_pods = external_podspecs ? Dir.glob(external_podspecs) : []
      additional_path_pods = (include_podspecs ? Dir.glob(include_podspecs) : []) .select { |path| spec.name != Specification.from_file(path).name } - additional_podspec_pods

      Pod::Podfile.new do
        install! 'cocoapods', :deterministic_uuids => false
        # By default inhibit warnings for all pods, except the one being validated.
        inhibit_all_warnings!
        urls.each { |u| source(u) }
        target 'App' do
          if use_static_frameworks
            use_frameworks!(:linkage => :static)
          else
            use_frameworks!(use_frameworks)
          end
          use_modular_headers! if use_modular_headers
          platform(platform_name, deployment_target)
          if local
            pod name, :path => podspec.dirname.to_s, :inhibit_warnings => false
          else
            pod name, :podspec => podspec.to_s, :inhibit_warnings => false
          end

          additional_path_pods.each do |podspec_path|
            podspec_name = File.basename(podspec_path, '.*')
            pod podspec_name, :path => File.dirname(podspec_path)
          end

          additional_podspec_pods.each do |podspec_path|
            podspec_name = File.basename(podspec_path, '.*')
            pod podspec_name, :podspec => podspec_path
          end

          test_spec_names.each do |test_spec_name|
            if local
              pod test_spec_name, :path => podspec.dirname.to_s, :inhibit_warnings => false
            else
              pod test_spec_name, :podspec => podspec.to_s, :inhibit_warnings => false
            end
          end
        end
      end
    end

    # Parse the xcode build output to identify the lines which are relevant
    # to the linter.
    #
    # @param  [String] output the output generated by the xcodebuild tool.
    #
    # @note   The indentation and the temporary path is stripped form the
    #         lines.
    #
    # @return [Array<String>] the lines that are relevant to the linter.
    #
    def parse_xcodebuild_output(output)
      lines = output.split("\n")
      selected_lines = lines.select do |l|
        l.include?('error: ') && (l !~ /errors? generated\./) && (l !~ /error: \(null\)/) ||
          l.include?('warning: ') && (l !~ /warnings? generated\./) && (l !~ /frameworks only run on iOS 8/) ||
          l.include?('note: ') && (l !~ /expanded from macro/)
      end
      selected_lines.map do |l|
        new = l.gsub(%r{#{validation_dir}/Pods/}, '')
        new.gsub!(/^ */, ' ')
      end
    end

    # @return [String] Executes xcodebuild in the current working directory and
    #         returns its output (both STDOUT and STDERR).
    #
    def xcodebuild(action, scheme, configuration)
      require 'fourflusher'
      command = %W(clean #{action} -workspace #{File.join(validation_dir, 'App.xcworkspace')} -scheme #{scheme} -configuration #{configuration})
      case consumer.platform_name
      when :osx, :macos
        command += %w(CODE_SIGN_IDENTITY=)
      when :ios
        command += %w(CODE_SIGN_IDENTITY=- -sdk iphonesimulator)
        command += Fourflusher::SimControl.new.destination(:oldest, 'iOS', deployment_target)
        xcconfig = consumer.pod_target_xcconfig
        if xcconfig
          archs = xcconfig['VALID_ARCHS']
          if archs && (archs.include? 'armv7') && !(archs.include? 'i386') && (archs.include? 'x86_64')
            # Prevent Xcodebuild from testing the non-existent i386 simulator if armv7 is specified without i386
            command += %w(ARCHS=x86_64)
          end
        end
      when :watchos
        command += %w(CODE_SIGN_IDENTITY=- -sdk watchsimulator)
        command += Fourflusher::SimControl.new.destination(:oldest, 'watchOS', deployment_target)
      when :tvos
        command += %w(CODE_SIGN_IDENTITY=- -sdk appletvsimulator)
        command += Fourflusher::SimControl.new.destination(:oldest, 'tvOS', deployment_target)
      end

      if analyze
        command += %w(CLANG_ANALYZER_OUTPUT=html CLANG_ANALYZER_OUTPUT_DIR=analyzer)
      end

      begin
        _xcodebuild(command, true)
      rescue => e
        message = 'Returned an unsuccessful exit code.'
        message += ' You can use `--verbose` for more information.' unless config.verbose?
        error('xcodebuild', message)
        e.message
      end
    end

    # Executes the given command in the current working directory.
    #
    # @return [String] The output of the given command
    #
    def _xcodebuild(command, raise_on_failure = false)
      Executable.execute_command('xcodebuild', command, raise_on_failure)
    end

    # Whether the platform with the specified name is valid
    #
    # @param  [Platform] platform
    #         The platform to check
    #
    # @return [Bool] True if the platform is valid
    #
    def valid_platform?(platform)
      VALID_PLATFORMS.any? { |p| p.name == platform.name }
    end

    # Whether the platform is supported by the specification
    #
    # @param  [Platform] platform
    #         The platform to check
    #
    # @param  [Specification] spec
    #         The specification which must support the provided platform
    #
    # @return [Bool] Whether the platform is supported by the specification
    #
    def supported_platform?(platform, spec)
      available_platforms = spec.available_platforms

      available_platforms.any? { |p| p.name == platform.name }
    end

    # Whether the provided name matches the platform
    #
    # @param  [Platform] platform
    #         The platform
    #
    # @param  [String] name
    #         The name to check against the provided platform
    #
    def platform_name_match?(platform, name)
      [platform.name, platform.string_name].any? { |n| n.casecmp(name) == 0 }
    end

    #-------------------------------------------------------------------------#
  end
end