path: root/Library/Homebrew/diagnostic.rb

require "keg"
require "language/python"
require "formula"
require "version"

module Homebrew
  module Diagnostic
    def self.missing_deps(ff)
      missing = {}
      ff.each do |f|
        missing_deps = f.recursive_dependencies do |dependent, dep|
          if dep.optional? || dep.recommended?
            tab = Tab.for_formula(dependent)
            Dependency.prune unless tab.with?(dep)
          elsif dep.build?
            Dependency.prune
          end
        end

        missing_deps.map!(&:to_formula)
        missing_deps.reject! { |d| d.installed_prefixes.any? }

        unless missing_deps.empty?
          yield f.full_name, missing_deps if block_given?
          missing[f.full_name] = missing_deps
        end
      end
      missing
    end

    class Volumes
      def initialize
        @volumes = get_mounts
      end

      def which(path)
        vols = get_mounts path

        # no volume found
        if vols.empty?
          return -1
        end

        vol_index = @volumes.index(vols[0])
        # volume not found in volume list
        if vol_index.nil?
          return -1
        end
        vol_index
      end

      def get_mounts(path = nil)
        vols = []
        # get the volume of path, if path is nil returns all volumes

        args = %w[/bin/df -P]
        args << path if path

        Utils.popen_read(*args) do |io|
          io.each_line do |line|
            case line.chomp
              # regex matches: /dev/disk0s2   489562928 440803616  48247312    91%    /
            when /^.+\s+[0-9]+\s+[0-9]+\s+[0-9]+\s+[0-9]{1,3}%\s+(.+)/
              vols << $1
            end
          end
        end
        vols
      end
    end

    class Checks
      ############# HELPERS
      # Finds files in HOMEBREW_PREFIX *and* /usr/local.
      # Specify paths relative to a prefix eg. "include/foo.h".
      # Sets @found for your convenience.
      def find_relative_paths(*relative_paths)
        @found = [HOMEBREW_PREFIX, "/usr/local"].uniq.inject([]) do |found, prefix|
          found + relative_paths.map { |f| File.join(prefix, f) }.select { |f| File.exist? f }
        end
      end

      def inject_file_list(list, str)
        list.inject(str) { |s, f| s << "    #{f}\n" }
      end
      ############# END HELPERS

      def inject_dump_stats!
        self.extend Module.new {
          def send(method, *)
            time = Time.now
            super
          ensure
            $times[method] = Time.now - time
          end
        }
        $times = {}
        at_exit do
          puts $times.sort_by { |_k, v| v }.map { |k, v| "#{k}: #{v}" }
        end
      end

      # See https://github.com/Homebrew/homebrew/pull/9986
      def check_path_for_trailing_slashes
        bad_paths = ENV["PATH"].split(File::PATH_SEPARATOR).select { |p| p[-1..-1] == "/" }
        return if bad_paths.empty?
        inject_file_list bad_paths, <<-EOS.undent
          Some directories in your path end in a slash.
          Directories in your path should not end in a slash. This can break other
          doctor checks. The following directories should be edited:
        EOS
      end

      # Installing MacGPG2 interferes with Homebrew in a big way
      # https://github.com/GPGTools/MacGPG2
      def check_for_macgpg2
        return if File.exist? "/usr/local/MacGPG2/share/gnupg/VERSION"

        suspects = %w[
          /Applications/start-gpg-agent.app
          /Library/Receipts/libiconv1.pkg
          /usr/local/MacGPG2
        ]

        if suspects.any? { |f| File.exist? f } then <<-EOS.undent
          You may have installed MacGPG2 via the package installer.
          Several other checks in this script will turn up problems, such as stray
          dylibs in /usr/local and permissions issues with share and man in /usr/local/.
        EOS
        end
      end

      # Anaconda installs multiple system & brew dupes, including OpenSSL, Python,
      # sqlite, libpng, Qt, etc. Regularly breaks compile on Vim, MacVim and others.
      # Is flagged as part of the *-config script checks below, but people seem
      # to ignore those as warnings rather than extremely likely breakage.
      def check_for_anaconda
        return unless which("anaconda")
        return unless which("python")

        anaconda = which("anaconda").realpath.dirname
        python_binary = Utils.popen_read which("python"), "-c", "import sys; sys.stdout.write(sys.executable)"
        python = Pathname.new(python_binary).realpath.dirname

        # Only warn if Python lives with Anaconda, since is most problematic case.
        if python == anaconda then <<-EOS.undent
          Anaconda is known to frequently break Homebrew builds, including Vim and
          MacVim, due to bundling many duplicates of system and Homebrew-available
          tools.

          If you encounter a build failure please temporarily remove Anaconda
          from your $PATH and attempt the build again prior to reporting the
          failure to us. Thanks!
        EOS
        end
      end

      def __check_stray_files(dir, pattern, white_list, message)
        return unless File.directory?(dir)

        files = Dir.chdir(dir) do
          Dir[pattern].select { |f| File.file?(f) && !File.symlink?(f) } - Dir.glob(white_list)
        end.map { |file| File.join(dir, file) }

        inject_file_list(files, message) unless files.empty?
      end

      def check_for_stray_dylibs
        # Dylibs which are generally OK should be added to this list,
        # with a short description of the software they come with.
        white_list = [
          "libfuse.2.dylib", # MacFuse
          "libfuse_ino64.2.dylib", # MacFuse
          "libmacfuse_i32.2.dylib", # OSXFuse MacFuse compatibility layer
          "libmacfuse_i64.2.dylib", # OSXFuse MacFuse compatibility layer
          "libosxfuse_i32.2.dylib", # OSXFuse
          "libosxfuse_i64.2.dylib", # OSXFuse
          "libosxfuse.2.dylib", # OSXFuse
          "libTrAPI.dylib", # TrAPI / Endpoint Security VPN
          "libntfs-3g.*.dylib", # NTFS-3G
          "libntfs.*.dylib", # NTFS-3G
          "libublio.*.dylib", # NTFS-3G
          "libUFSDNTFS.dylib", # Paragon NTFS
          "libUFSDExtFS.dylib", # Paragon ExtFS
        ]

        __check_stray_files "/usr/local/lib", "*.dylib", white_list, <<-EOS.undent
        Unbrewed dylibs were found in /usr/local/lib.
        If you didn't put them there on purpose they could cause problems when
        building Homebrew formulae, and may need to be deleted.

        Unexpected dylibs:
      EOS
      end

      def check_for_stray_static_libs
        # Static libs which are generally OK should be added to this list,
        # with a short description of the software they come with.
        white_list = [
          "libsecurity_agent_client.a", # OS X 10.8.2 Supplemental Update
          "libsecurity_agent_server.a", # OS X 10.8.2 Supplemental Update
          "libntfs-3g.a", # NTFS-3G
          "libntfs.a", # NTFS-3G
          "libublio.a", # NTFS-3G
        ]

        __check_stray_files "/usr/local/lib", "*.a", white_list, <<-EOS.undent
        Unbrewed static libraries were found in /usr/local/lib.
        If you didn't put them there on purpose they could cause problems when
        building Homebrew formulae, and may need to be deleted.

        Unexpected static libraries:
      EOS
      end

      def check_for_stray_pcs
        # Package-config files which are generally OK should be added to this list,
        # with a short description of the software they come with.
        white_list = [
          "fuse.pc", # OSXFuse/MacFuse
          "macfuse.pc", # OSXFuse MacFuse compatibility layer
          "osxfuse.pc", # OSXFuse
          "libntfs-3g.pc", # NTFS-3G
          "libublio.pc", # NTFS-3G
        ]

        __check_stray_files "/usr/local/lib/pkgconfig", "*.pc", white_list, <<-EOS.undent
        Unbrewed .pc files were found in /usr/local/lib/pkgconfig.
        If you didn't put them there on purpose they could cause problems when
        building Homebrew formulae, and may need to be deleted.

        Unexpected .pc files:
      EOS
      end

      def check_for_stray_las
        white_list = [
          "libfuse.la", # MacFuse
          "libfuse_ino64.la", # MacFuse
          "libosxfuse_i32.la", # OSXFuse
          "libosxfuse_i64.la", # OSXFuse
          "libosxfuse.la", # OSXFuse
          "libntfs-3g.la", # NTFS-3G
          "libntfs.la", # NTFS-3G
          "libublio.la", # NTFS-3G
        ]

        __check_stray_files "/usr/local/lib", "*.la", white_list, <<-EOS.undent
        Unbrewed .la files were found in /usr/local/lib.
        If you didn't put them there on purpose they could cause problems when
        building Homebrew formulae, and may need to be deleted.

        Unexpected .la files:
      EOS
      end

      def check_for_stray_headers
        white_list = [
          "fuse.h", # MacFuse
          "fuse/**/*.h", # MacFuse
          "macfuse/**/*.h", # OSXFuse MacFuse compatibility layer
          "osxfuse/**/*.h", # OSXFuse
          "ntfs/**/*.h", # NTFS-3G
          "ntfs-3g/**/*.h", # NTFS-3G
        ]

        __check_stray_files "/usr/local/include", "**/*.h", white_list, <<-EOS.undent
        Unbrewed header files were found in /usr/local/include.
        If you didn't put them there on purpose they could cause problems when
        building Homebrew formulae, and may need to be deleted.

        Unexpected header files:
      EOS
      end

      def check_for_other_package_managers
        ponk = MacOS.macports_or_fink
        unless ponk.empty?
          <<-EOS.undent
          You have MacPorts or Fink installed:
            #{ponk.join(", ")}

          This can cause trouble. You don't have to uninstall them, but you may want to
          temporarily move them out of the way, e.g.

            sudo mv /opt/local ~/macports
        EOS
        end
      end

      def check_for_broken_symlinks
        broken_symlinks = []

        Keg::PRUNEABLE_DIRECTORIES.each do |d|
          next unless d.directory?
          d.find do |path|
            if path.symlink? && !path.resolved_path_exists?
              broken_symlinks << path
            end
          end
        end
        return if broken_symlinks.empty?
        inject_file_list broken_symlinks, <<-EOS.undent
        Broken symlinks were found. Remove them with `brew prune`:
        EOS
      end

      def check_for_unsupported_osx
        return if ARGV.homebrew_developer?
        if OS::Mac.prerelease?
          <<-EOS.undent
            You are using OS X #{MacOS.version}.
            We do not provide support for this pre-release version.
            You may encounter build failures or other breakages.
          EOS
        elsif OS::Mac.outdated_release?
          <<-EOS.undent
            You are using OS X #{MacOS.version}.
            We (and Apple) do not provide support for this old version.
            You may encounter build failures or other breakages.
          EOS
        end
      end

      # TODO: distill down into single method definition a la BuildToolsError
      if MacOS.version >= "10.9"
        def check_for_installed_developer_tools
          unless MacOS::Xcode.installed? || MacOS::CLT.installed? then <<-EOS.undent
          No developer tools installed.
          Install the Command Line Tools:
            xcode-select --install
          EOS
          end
        end

        if OS::Mac.prerelease?
          def check_xcode_up_to_date
            if MacOS::Xcode.installed? && MacOS::Xcode.outdated?
              <<-EOS.undent
            Your Xcode (#{MacOS::Xcode.version}) is outdated
            Please update to Xcode #{MacOS::Xcode.latest_version}.
            Xcode can be updated from
              https://developer.apple.com/xcode/downloads/
            EOS
            end
          end
        else
          def check_xcode_up_to_date
            if MacOS::Xcode.installed? && MacOS::Xcode.outdated?
              <<-EOS.undent
            Your Xcode (#{MacOS::Xcode.version}) is outdated
            Please update to Xcode #{MacOS::Xcode.latest_version}.
            Xcode can be updated from the App Store.
            EOS
            end
          end
        end

        def check_clt_up_to_date
          if MacOS::CLT.installed? && MacOS::CLT.outdated? then <<-EOS.undent
          A newer Command Line Tools release is available.
          Update them from Software Update in the App Store.
          EOS
          end
        end
      elsif MacOS.version == "10.8" || MacOS.version == "10.7"
        def check_for_installed_developer_tools
          unless MacOS::Xcode.installed? || MacOS::CLT.installed? then <<-EOS.undent
          No developer tools installed.
          You should install the Command Line Tools.
          The standalone package can be obtained from
            https://developer.apple.com/downloads
          or it can be installed via Xcode's preferences.
          EOS
          end
        end

        def check_xcode_up_to_date
          if MacOS::Xcode.installed? && MacOS::Xcode.outdated? then <<-EOS.undent
          Your Xcode (#{MacOS::Xcode.version}) is outdated
          Please update to Xcode #{MacOS::Xcode.latest_version}.
          Xcode can be updated from
            https://developer.apple.com/xcode/downloads/
          EOS
          end
        end

        def check_clt_up_to_date
          if MacOS::CLT.installed? && MacOS::CLT.outdated? then <<-EOS.undent
          A newer Command Line Tools release is available.
          The standalone package can be obtained from
            https://developer.apple.com/downloads
          or it can be installed via Xcode's preferences.
          EOS
          end
        end
      else
        def check_for_installed_developer_tools
          unless MacOS::Xcode.installed? then <<-EOS.undent
          Xcode is not installed. Most formulae need Xcode to build.
          It can be installed from
            https://developer.apple.com/xcode/downloads/
          EOS
          end
        end

        def check_xcode_up_to_date
          if MacOS::Xcode.installed? && MacOS::Xcode.outdated? then <<-EOS.undent
          Your Xcode (#{MacOS::Xcode.version}) is outdated
          Please update to Xcode #{MacOS::Xcode.latest_version}.
          Xcode can be updated from
            https://developer.apple.com/xcode/downloads/
          EOS
          end
        end
      end

      def check_for_osx_gcc_installer
        if (MacOS.version < "10.7" || MacOS::Xcode.version > "4.1") && \
          MacOS.clang_version == "2.1"
          message = <<-EOS.undent
        You seem to have osx-gcc-installer installed.
        Homebrew doesn't support osx-gcc-installer. It causes many builds to fail and
        is an unlicensed distribution of really old Xcode files.
        EOS
          if MacOS.version >= :mavericks
            message += <<-EOS.undent
              Please run `xcode-select --install` to install the CLT.
            EOS
          elsif MacOS.version >= :lion
            message += <<-EOS.undent
            Please install the CLT or Xcode #{MacOS::Xcode.latest_version}.
          EOS
          else
            message += <<-EOS.undent
            Please install Xcode #{MacOS::Xcode.latest_version}.
          EOS
          end
        end
      end

      def check_for_stray_developer_directory
        # if the uninstaller script isn't there, it's a good guess neither are
        # any troublesome leftover Xcode files
        uninstaller = Pathname.new("/Developer/Library/uninstall-developer-folder")
        if MacOS::Xcode.version >= "4.3" && uninstaller.exist? then <<-EOS.undent
        You have leftover files from an older version of Xcode.
        You should delete them using:
          #{uninstaller}
        EOS
        end
      end

      def check_for_bad_install_name_tool
        return if MacOS.version < "10.9"

        install_name_tool = OS::Mac.install_name_tool
        libs = Pathname.new(install_name_tool).dynamically_linked_libraries

        # otool may not work, for example if the Xcode license hasn't been accepted yet
        return if libs.empty?

        expectedLibs = ["/usr/lib/libSystem.B.dylib", "/usr/lib/libxcselect.dylib"]
        if (libs & expectedLibs).empty? then <<-EOS.undent
        You have an outdated version of #{install_name_tool} installed.
        This will cause binary package installations to fail.
        This can happen if you install osx-gcc-installer or RailsInstaller.
        To restore it, you must reinstall OS X or restore the binary from
        the OS packages.
        EOS
        end
      end

      def __check_subdir_access(base)
        target = HOMEBREW_PREFIX+base
        return unless target.exist?

        cant_read = []

        target.find do |d|
          next unless d.directory?
          cant_read << d unless d.writable_real?
        end

        return if cant_read.empty?
        inject_file_list cant_read.sort, <<-EOS.undent
          Some directories in #{target} aren't writable.
          This can happen if you "sudo make install" software that isn't managed
          by Homebrew. If a brew tries to add locale information to one of these
          directories, then the install will fail during the link step.

          You should probably `sudo chown -R $(whoami)` them:
        EOS
      end

      def check_access_share_locale
        __check_subdir_access "share/locale"
      end

      def check_access_share_man
        __check_subdir_access "share/man"
      end

      def check_access_homebrew_repository
        unless HOMEBREW_REPOSITORY.writable_real? then <<-EOS.undent
          #{HOMEBREW_REPOSITORY} is not writable.

          You should probably change the ownership and permissions of #{HOMEBREW_REPOSITORY}
          back to your user account.
            sudo chown -R $(whoami) #{HOMEBREW_REPOSITORY}
        EOS
        end
      end

      def check_access_usr_local
        return unless HOMEBREW_PREFIX.to_s == "/usr/local"

        unless HOMEBREW_PREFIX.writable_real? then <<-EOS.undent
        /usr/local is not writable.
        Even if this directory was writable when you installed Homebrew, other
        software may change permissions on this directory. For example, upgrading
        to OS X El Capitan has been known to do this. Some versions of the
        "InstantOn" component of Airfoil or running Cocktail cleanup/optimizations
        are known to do this as well.

        You should probably change the ownership and permissions of /usr/local
        back to your user account.
          sudo chown -R $(whoami) /usr/local
        EOS
        end
      end

      def check_tmpdir_sticky_bit
        # Repair Disk Permissions was removed(?) in El Capitan.
        # https://support.apple.com/en-us/HT201560
        if MacOS.version < "10.11"
          fix_message = "Please run \"Repair Disk Permissions\" in Disk Utility."
        else
          fix_message = "Please execute `sudo chmod +t #{HOMEBREW_TEMP}` in your Terminal"
        end

        world_writable = HOMEBREW_TEMP.stat.mode & 0777 == 0777
        if world_writable && !HOMEBREW_TEMP.sticky? then <<-EOS.undent
        #{HOMEBREW_TEMP} is world-writable but does not have the sticky bit set.
        #{fix_message}
        EOS
        end
      end

      (Keg::TOP_LEVEL_DIRECTORIES + ["lib/pkgconfig"]).each do |d|
        define_method("check_access_#{d.sub("/", "_")}") do
          dir = HOMEBREW_PREFIX.join(d)
          if dir.exist? && !dir.writable_real? then <<-EOS.undent
          #{dir} isn't writable.

          This can happen if you "sudo make install" software that isn't managed
          by Homebrew. If a formula tries to write a file to this directory, the
          install will fail during the link step.

          You should probably change the ownership and permissions of #{dir}
          back to your user account.
            sudo chown -R $(whoami) #{dir}
          EOS
          end
        end
      end

      def check_access_site_packages
        if Language::Python.homebrew_site_packages.exist? && !Language::Python.homebrew_site_packages.writable_real?
          <<-EOS.undent
          #{Language::Python.homebrew_site_packages} isn't writable.
          This can happen if you "sudo pip install" software that isn't managed
          by Homebrew. If you install a formula with Python modules, the install
          will fail during the link step.

          You should probably change the ownership and permissions of #{Language::Python.homebrew_site_packages}
          back to your user account.
            sudo chown -R $(whoami) #{Language::Python.homebrew_site_packages}
        EOS
        end
      end

      def check_access_logs
        if HOMEBREW_LOGS.exist? && !HOMEBREW_LOGS.writable_real?
          <<-EOS.undent
          #{HOMEBREW_LOGS} isn't writable.
          Homebrew writes debugging logs to this location.

          You should probably change the ownership and permissions of #{HOMEBREW_LOGS}
          back to your user account.
            sudo chown -R $(whoami) #{HOMEBREW_LOGS}
        EOS
        end
      end

      def check_access_cache
        if HOMEBREW_CACHE.exist? && !HOMEBREW_CACHE.writable_real?
          <<-EOS.undent
          #{HOMEBREW_CACHE} isn't writable.
          This can happen if you run `brew install` or `brew fetch` as another user.
          Homebrew caches downloaded files to this location.

          You should probably change the ownership and permissions of #{HOMEBREW_CACHE}
          back to your user account.
            sudo chown -R $(whoami) #{HOMEBREW_CACHE}
        EOS
        end
      end

      def check_access_cellar
        if HOMEBREW_CELLAR.exist? && !HOMEBREW_CELLAR.writable_real?
          <<-EOS.undent
          #{HOMEBREW_CELLAR} isn't writable.

          You should probably change the ownership and permissions of #{HOMEBREW_CELLAR}
          back to your user account.
            sudo chown -R $(whoami) #{HOMEBREW_CELLAR}
        EOS
        end
      end

      def check_access_prefix_opt
        opt = HOMEBREW_PREFIX.join("opt")
        if opt.exist? && !opt.writable_real?
          <<-EOS.undent
          #{opt} isn't writable.
          You should probably change the ownership and permissions of #{opt}
          back to your user account.
            sudo chown -R $(whoami) #{opt}
        EOS
        end
      end

      def check_ruby_version
        ruby_version = MacOS.version >= "10.9" ? "2.0" : "1.8"
        if RUBY_VERSION[/\d\.\d/] != ruby_version then <<-EOS.undent
        Ruby version #{RUBY_VERSION} is unsupported on #{MacOS.version}. Homebrew
        is developed and tested on Ruby #{ruby_version}, and may not work correctly
        on other Rubies. Patches are accepted as long as they don't cause breakage
        on supported Rubies.
        EOS
        end
      end

      def check_homebrew_prefix
        unless HOMEBREW_PREFIX.to_s == "/usr/local"
          <<-EOS.undent
          Your Homebrew is not installed to /usr/local
          You can install Homebrew anywhere you want, but some brews may only build
          correctly if you install in /usr/local. Sorry!
        EOS
        end
      end

      def check_xcode_prefix
        prefix = MacOS::Xcode.prefix
        return if prefix.nil?
        if prefix.to_s.match(" ")
          <<-EOS.undent
          Xcode is installed to a directory with a space in the name.
          This will cause some formulae to fail to build.
        EOS
        end
      end

      def check_xcode_prefix_exists
        prefix = MacOS::Xcode.prefix
        return if prefix.nil?
        unless prefix.exist?
          <<-EOS.undent
          The directory Xcode is reportedly installed to doesn't exist:
            #{prefix}
          You may need to `xcode-select` the proper path if you have moved Xcode.
        EOS
        end
      end

      def check_xcode_select_path
        if !MacOS::CLT.installed? && !File.file?("#{MacOS.active_developer_dir}/usr/bin/xcodebuild")
          path = MacOS::Xcode.bundle_path
          path = "/Developer" if path.nil? || !path.directory?
          <<-EOS.undent
          Your Xcode is configured with an invalid path.
          You should change it to the correct path:
            sudo xcode-select -switch #{path}
        EOS
        end
      end

      def check_user_path_1
        $seen_prefix_bin = false
        $seen_prefix_sbin = false

        out = nil

        paths.each do |p|
          case p
          when "/usr/bin"
            unless $seen_prefix_bin
              # only show the doctor message if there are any conflicts
              # rationale: a default install should not trigger any brew doctor messages
              conflicts = Dir["#{HOMEBREW_PREFIX}/bin/*"].
                          map { |fn| File.basename fn }.
                          select { |bn| File.exist? "/usr/bin/#{bn}" }

              if conflicts.size > 0
                out = inject_file_list conflicts, <<-EOS.undent
                /usr/bin occurs before #{HOMEBREW_PREFIX}/bin
                This means that system-provided programs will be used instead of those
                provided by Homebrew. The following tools exist at both paths:
                EOS

                out += <<-EOS.undent

                Consider setting your PATH so that #{HOMEBREW_PREFIX}/bin
                occurs before /usr/bin. Here is a one-liner:
                    echo 'export PATH="#{HOMEBREW_PREFIX}/bin:$PATH"' >> #{shell_profile}
              EOS
              end
            end
          when "#{HOMEBREW_PREFIX}/bin"
            $seen_prefix_bin = true
          when "#{HOMEBREW_PREFIX}/sbin"
            $seen_prefix_sbin = true
          end
        end
        out
      end

      def check_user_path_2
        unless $seen_prefix_bin
          <<-EOS.undent
          Homebrew's bin was not found in your PATH.
          Consider setting the PATH for example like so
              echo 'export PATH="#{HOMEBREW_PREFIX}/bin:$PATH"' >> #{shell_profile}
        EOS
        end
      end

      def check_user_path_3
        # Don't complain about sbin not being in the path if it doesn't exist
        sbin = (HOMEBREW_PREFIX+"sbin")
        if sbin.directory? && sbin.children.length > 0
          unless $seen_prefix_sbin
            <<-EOS.undent
            Homebrew's sbin was not found in your PATH but you have installed
            formulae that put executables in #{HOMEBREW_PREFIX}/sbin.
            Consider setting the PATH for example like so
                echo 'export PATH="#{HOMEBREW_PREFIX}/sbin:$PATH"' >> #{shell_profile}
          EOS
          end
        end
      end

      def check_for_bad_curl
        if MacOS.version <= "10.8" && !Formula["curl"].installed? then <<-EOS.undent
          The system curl on 10.8 and below is often incapable of supporting
          modern secure connections & will fail on fetching formulae.

          We recommend you:
            brew install curl
          EOS
        end
      end

      def check_user_curlrc
        if %w[CURL_HOME HOME].any? { |key| ENV[key] && File.exist?("#{ENV[key]}/.curlrc") } then <<-EOS.undent
        You have a curlrc file
        If you have trouble downloading packages with Homebrew, then maybe this
        is the problem? If the following command doesn't work, then try removing
        your curlrc:
          curl https://github.com
        EOS
        end
      end

      def check_for_unsupported_curl_vars
        # Support for SSL_CERT_DIR seemed to be removed in the 10.10.5 update.
        if MacOS.version >= :yosemite && !ENV["SSL_CERT_DIR"].nil? then <<-EOS.undent
          SSL_CERT_DIR support was removed from Apple's curl.
          If fetching formulae fails you should:
            unset SSL_CERT_DIR
          and remove it from #{shell_profile} if present.
          EOS
        end
      end

      def check_which_pkg_config
        binary = which "pkg-config"
        return if binary.nil?

        mono_config = Pathname.new("/usr/bin/pkg-config")
        if mono_config.exist? && mono_config.realpath.to_s.include?("Mono.framework") then <<-EOS.undent
        You have a non-Homebrew 'pkg-config' in your PATH:
          /usr/bin/pkg-config => #{mono_config.realpath}

        This was most likely created by the Mono installer. `./configure` may
        have problems finding brew-installed packages using this other pkg-config.

        Mono no longer installs this file as of 3.0.4. You should
        `sudo rm /usr/bin/pkg-config` and upgrade to the latest version of Mono.
        EOS
        elsif binary.to_s != "#{HOMEBREW_PREFIX}/bin/pkg-config" then <<-EOS.undent
        You have a non-Homebrew 'pkg-config' in your PATH:
          #{binary}

        `./configure` may have problems finding brew-installed packages using
        this other pkg-config.
        EOS
        end
      end

      def check_for_gettext
        find_relative_paths("lib/libgettextlib.dylib",
                            "lib/libintl.dylib",
                            "include/libintl.h")

        return if @found.empty?

        # Our gettext formula will be caught by check_linked_keg_only_brews
        f = Formulary.factory("gettext") rescue nil
        return if f && f.linked_keg.directory? && @found.all? do |path|
          Pathname.new(path).realpath.to_s.start_with? "#{HOMEBREW_CELLAR}/gettext"
        end

        s = <<-EOS.undent_________________________________________________________72
          gettext files detected at a system prefix
          These files can cause compilation and link failures, especially if they
          are compiled with improper architectures. Consider removing these files:
          EOS
        inject_file_list(@found, s)
      end

      def check_for_iconv
        unless find_relative_paths("lib/libiconv.dylib", "include/iconv.h").empty?
          if (f = Formulary.factory("libiconv") rescue nil) && f.linked_keg.directory?
            unless f.keg_only? then <<-EOS.undent
            A libiconv formula is installed and linked
            This will break stuff. For serious. Unlink it.
            EOS
            end
          else
            s = <<-EOS.undent_________________________________________________________72
              libiconv files detected at a system prefix other than /usr
              Homebrew doesn't provide a libiconv formula, and expects to link against
              the system version in /usr. libiconv in other prefixes can cause
              compile or link failure, especially if compiled with improper
              architectures. OS X itself never installs anything to /usr/local so
              it was either installed by a user or some other third party software.

              tl;dr: delete these files:
              EOS
            inject_file_list(@found, s)
          end
        end
      end

      def check_for_config_scripts
        return unless HOMEBREW_CELLAR.exist?
        real_cellar = HOMEBREW_CELLAR.realpath

        scripts = []

        whitelist = %W[
          /usr/bin /usr/sbin
          /usr/X11/bin /usr/X11R6/bin /opt/X11/bin
          #{HOMEBREW_PREFIX}/bin #{HOMEBREW_PREFIX}/sbin
          /Applications/Server.app/Contents/ServerRoot/usr/bin
          /Applications/Server.app/Contents/ServerRoot/usr/sbin
        ].map(&:downcase)

        paths.each do |p|
          next if whitelist.include?(p.downcase) || !File.directory?(p)

          realpath = Pathname.new(p).realpath.to_s
          next if realpath.start_with?(real_cellar.to_s, HOMEBREW_CELLAR.to_s)

          scripts += Dir.chdir(p) { Dir["*-config"] }.map { |c| File.join(p, c) }
        end

        return if scripts.empty?
        inject_file_list scripts, <<-EOS.undent
          "config" scripts exist outside your system or Homebrew directories.
          `./configure` scripts often look for *-config scripts to determine if
          software packages are installed, and what additional flags to use when
          compiling and linking.

          Having additional scripts in your path can confuse software installed via
          Homebrew if the config script overrides a system or Homebrew provided
          script of the same name. We found the following "config" scripts:
        EOS
      end

      def check_DYLD_vars
        found = ENV.keys.grep(/^DYLD_/)
        return if found.empty?
        s = inject_file_list found.map { |e| "#{e}: #{ENV.fetch(e)}" }, <<-EOS.undent
          Setting DYLD_* vars can break dynamic linking.
          Set variables:
        EOS
        if found.include? "DYLD_INSERT_LIBRARIES"
          s += <<-EOS.undent

          Setting DYLD_INSERT_LIBRARIES can cause Go builds to fail.
          Having this set is common if you use this software:
            http://asepsis.binaryage.com/
          EOS
        end
        s
      end

      def check_for_symlinked_cellar
        return unless HOMEBREW_CELLAR.exist?
        if HOMEBREW_CELLAR.symlink?
          <<-EOS.undent
          Symlinked Cellars can cause problems.
          Your Homebrew Cellar is a symlink: #{HOMEBREW_CELLAR}
                          which resolves to: #{HOMEBREW_CELLAR.realpath}

          The recommended Homebrew installations are either:
          (A) Have Cellar be a real directory inside of your HOMEBREW_PREFIX
          (B) Symlink "bin/brew" into your prefix, but don't symlink "Cellar".

          Older installations of Homebrew may have created a symlinked Cellar, but this can
          cause problems when two formula install to locations that are mapped on top of each
          other during the linking step.
        EOS
        end
      end

      def check_for_multiple_volumes
        return unless HOMEBREW_CELLAR.exist?
        volumes = Volumes.new

        # Find the volumes for the TMP folder & HOMEBREW_CELLAR
        real_cellar = HOMEBREW_CELLAR.realpath

        tmp = Pathname.new(Dir.mktmpdir("doctor", HOMEBREW_TEMP))
        real_temp = tmp.realpath.parent

        where_cellar = volumes.which real_cellar
        where_temp = volumes.which real_temp

        Dir.delete tmp

        unless where_cellar == where_temp then <<-EOS.undent
        Your Cellar and TEMP directories are on different volumes.
        OS X won't move relative symlinks across volumes unless the target file already
        exists. Brews known to be affected by this are Git and Narwhal.

        You should set the "HOMEBREW_TEMP" environmental variable to a suitable
        directory on the same volume as your Cellar.
        EOS
        end
      end

      def check_filesystem_case_sensitive
        volumes = Volumes.new
        case_sensitive_vols = [HOMEBREW_PREFIX, HOMEBREW_REPOSITORY, HOMEBREW_CELLAR, HOMEBREW_TEMP].select do |dir|
          # We select the dir as being case-sensitive if either the UPCASED or the
          # downcased variant is missing.
          # Of course, on a case-insensitive fs, both exist because the os reports so.
          # In the rare situation when the user has indeed a downcased and an upcased
          # dir (e.g. /TMP and /tmp) this check falsely thinks it is case-insensitive
          # but we don't care beacuse: 1. there is more than one dir checked, 2. the
          # check is not vital and 3. we would have to touch files otherwise.
          upcased = Pathname.new(dir.to_s.upcase)
          downcased = Pathname.new(dir.to_s.downcase)
          dir.exist? && !(upcased.exist? && downcased.exist?)
        end.map { |case_sensitive_dir| volumes.get_mounts(case_sensitive_dir) }.uniq
        return if case_sensitive_vols.empty?
        <<-EOS.undent
        The filesystem on #{case_sensitive_vols.join(",")} appears to be case-sensitive.
        The default OS X filesystem is case-insensitive. Please report any apparent problems.
      EOS
      end

      def __check_git_version
        # https://help.github.com/articles/https-cloning-errors
        `git --version`.chomp =~ /git version ((?:\d+\.?)+)/

        if $1 && Version.new($1) < Version.new("1.7.10")
          git_upgrade_cmd = Formula["git"].any_version_installed? ? "upgrade" : "install"

          <<-EOS.undent
            An outdated version of Git was detected in your PATH.
            Git 1.7.10 or newer is required to perform checkouts over HTTPS from GitHub.
            Please upgrade: brew #{git_upgrade_cmd} git
          EOS
        end
      end

      def check_for_git
        if Utils.git_available?
          __check_git_version
        else <<-EOS.undent
        Git could not be found in your PATH.
        Homebrew uses Git for several internal functions, and some formulae use Git
        checkouts instead of stable tarballs. You may want to install Git:
          brew install git
        EOS
        end
      end

      def check_git_newline_settings
        return unless Utils.git_available?

        autocrlf = HOMEBREW_REPOSITORY.cd { `git config --get core.autocrlf`.chomp }

        if autocrlf == "true" then <<-EOS.undent
        Suspicious Git newline settings found.

        The detected Git newline settings will cause checkout problems:
          core.autocrlf = #{autocrlf}

        If you are not routinely dealing with Windows-based projects,
        consider removing these by running:
        `git config --global core.autocrlf input`
        EOS
        end
      end

      def check_git_origin
        return if !Utils.git_available? || !(HOMEBREW_REPOSITORY/".git").exist?

        origin = Homebrew.git_origin

        if origin.nil? then <<-EOS.undent
          Missing git origin remote.

          Without a correctly configured origin, Homebrew won't update
          properly. You can solve this by adding the Homebrew remote:
            cd #{HOMEBREW_REPOSITORY}
            git remote add origin https://github.com/Homebrew/homebrew.git
          EOS
        elsif origin !~ /(mxcl|Homebrew)\/homebrew(\.git)?$/ then <<-EOS.undent
          Suspicious git origin remote found.

          With a non-standard origin, Homebrew won't pull updates from
          the main repository. The current git origin is:
            #{origin}

          Unless you have compelling reasons, consider setting the
          origin remote to point at the main repository, located at:
            https://github.com/Homebrew/homebrew.git
          EOS
        end
      end

      def check_for_autoconf
        return unless MacOS::Xcode.installed?
        return unless MacOS::Xcode.provides_autotools?

        autoconf = which("autoconf")
        safe_autoconfs = %w[/usr/bin/autoconf /Developer/usr/bin/autoconf]
        unless autoconf.nil? || safe_autoconfs.include?(autoconf.to_s) then <<-EOS.undent
        An "autoconf" in your path blocks the Xcode-provided version at:
          #{autoconf}

        This custom autoconf may cause some Homebrew formulae to fail to compile.
        EOS
        end
      end

      def __check_linked_brew(f)
        f.installed_prefixes.each do |prefix|
          prefix.find do |src|
            next if src == prefix
            dst = HOMEBREW_PREFIX + src.relative_path_from(prefix)
            return true if dst.symlink? && src == dst.resolved_path
          end
        end

        false
      end

      def check_for_linked_keg_only_brews
        return unless HOMEBREW_CELLAR.exist?

        linked = Formula.installed.select do |f|
          f.keg_only? && __check_linked_brew(f)
        end

        return if linked.empty?
        inject_file_list linked.map(&:full_name), <<-EOS.undent
        Some keg-only formula are linked into the Cellar.
        Linking a keg-only formula, such as gettext, into the cellar with
        `brew link <formula>` will cause other formulae to detect them during
        the `./configure` step. This may cause problems when compiling those
        other formulae.

        Binaries provided by keg-only formulae may override system binaries
        with other strange results.

        You may wish to `brew unlink` these brews:
        EOS
      end

      def check_for_other_frameworks
        # Other frameworks that are known to cause problems when present
        %w[expat.framework libexpat.framework libcurl.framework].
          map { |frmwrk| "/Library/Frameworks/#{frmwrk}" }.
          select { |frmwrk| File.exist? frmwrk }.
          map do |frmwrk|
            <<-EOS.undent
          #{frmwrk} detected
          This can be picked up by CMake's build system and likely cause the build to
          fail. You may need to move this file out of the way to compile CMake.
          EOS
          end.join
      end

      def check_tmpdir
        tmpdir = ENV["TMPDIR"]
        "TMPDIR #{tmpdir.inspect} doesn't exist." unless tmpdir.nil? || File.directory?(tmpdir)
      end

      def check_missing_deps
        return unless HOMEBREW_CELLAR.exist?
        missing = Set.new
        Homebrew::Diagnostic.missing_deps(Formula.installed).each_value do |deps|
          missing.merge(deps)
        end

        if missing.any? then <<-EOS.undent
          Some installed formula are missing dependencies.
          You should `brew install` the missing dependencies:

              brew install #{missing.sort_by(&:full_name) * " "}

          Run `brew missing` for more details.
        EOS
        end
      end

      def check_git_status
        return unless Utils.git_available?
        HOMEBREW_REPOSITORY.cd do
          unless `git status --untracked-files=all --porcelain -- Library/Homebrew/ 2>/dev/null`.chomp.empty?
            <<-EOS.undent_________________________________________________________72
          You have uncommitted modifications to Homebrew
          If this is a surprise to you, then you should stash these modifications.
          Stashing returns Homebrew to a pristine state but can be undone
          should you later need to do so for some reason.
              cd #{HOMEBREW_LIBRARY} && git stash && git clean -d -f
          EOS
          end
        end
      end

      def check_for_enthought_python
        if which "enpkg" then <<-EOS.undent
        Enthought Python was found in your PATH.
        This can cause build problems, as this software installs its own
        copies of iconv and libxml2 into directories that are picked up by
        other build systems.
        EOS
        end
      end

      def check_for_library_python
        if File.exist?("/Library/Frameworks/Python.framework") then <<-EOS.undent
        Python is installed at /Library/Frameworks/Python.framework

        Homebrew only supports building against the System-provided Python or a
        brewed Python. In particular, Pythons installed to /Library can interfere
        with other software installs.
        EOS
        end
      end

      def check_for_old_homebrew_share_python_in_path
        s = ""
        ["", "3"].map do |suffix|
          if paths.include?((HOMEBREW_PREFIX/"share/python#{suffix}").to_s)
            s += "#{HOMEBREW_PREFIX}/share/python#{suffix} is not needed in PATH.\n"
          end
        end
        unless s.empty?
          s += <<-EOS.undent
          Formerly homebrew put Python scripts you installed via `pip` or `pip3`
          (or `easy_install`) into that directory above but now it can be removed
          from your PATH variable.
          Python scripts will now install into #{HOMEBREW_PREFIX}/bin.
          You can delete anything, except 'Extras', from the #{HOMEBREW_PREFIX}/share/python
          (and #{HOMEBREW_PREFIX}/share/python3) dir and install affected Python packages
          anew with `pip install --upgrade`.
        EOS
        end
      end

      def check_for_bad_python_symlink
        return unless which "python"
        `python -V 2>&1` =~ /Python (\d+)\./
        # This won't be the right warning if we matched nothing at all
        return if $1.nil?
        unless $1 == "2" then <<-EOS.undent
        python is symlinked to python#{$1}
        This will confuse build scripts and in general lead to subtle breakage.
        EOS
        end
      end

      def check_for_non_prefixed_coreutils
        coreutils = Formula["coreutils"]
        return unless coreutils.any_version_installed?

        gnubin = %W[#{coreutils.opt_libexec}/gnubin #{coreutils.libexec}/gnubin]
        return if (paths & gnubin).empty?

        <<-EOS.undent
          Putting non-prefixed coreutils in your path can cause gmp builds to fail.
        EOS
      end

      def check_for_non_prefixed_findutils
        findutils = Formula["findutils"]
        return unless findutils.any_version_installed?

        gnubin = %W[#{findutils.opt_libexec}/gnubin #{findutils.libexec}/gnubin]
        default_names = Tab.for_name("findutils").with? "default-names"
        return if !default_names && (paths & gnubin).empty?

        <<-EOS.undent
          Putting non-prefixed findutils in your path can cause python builds to fail.
        EOS
      end

      def check_for_pydistutils_cfg_in_home
        if File.exist? "#{ENV["HOME"]}/.pydistutils.cfg" then <<-EOS.undent
        A .pydistutils.cfg file was found in $HOME, which may cause Python
        builds to fail. See:
          https://bugs.python.org/issue6138
          https://bugs.python.org/issue4655
        EOS
        end
      end

      def check_for_outdated_homebrew
        return unless Utils.git_available?

        timestamp = if File.directory?("#{HOMEBREW_REPOSITORY}/.git")
          HOMEBREW_REPOSITORY.cd { `git log -1 --format="%ct" HEAD`.to_i }
        else
          HOMEBREW_LIBRARY.mtime.to_i
        end
        return if Time.now.to_i - timestamp <= 60 * 60 * 24 # 24 hours

        if File.directory?("#{HOMEBREW_REPOSITORY}/.git")
          HOMEBREW_REPOSITORY.cd do
            local = `git rev-parse -q --verify refs/remotes/origin/master`.chomp
            remote = /^([a-f0-9]{40})/.match(`git ls-remote origin refs/heads/master 2>/dev/null`)
            return if remote.nil? || local == remote[0]
          end
        end

        <<-EOS.undent
          Your Homebrew is outdated.
          You haven't updated for at least 24 hours. This is a long time in brewland!
          To update Homebrew, run `brew update`.
        EOS
      end

      def check_for_unlinked_but_not_keg_only
        unlinked = Formula.racks.reject do |rack|
          if !(HOMEBREW_REPOSITORY/"Library/LinkedKegs"/rack.basename).directory?
            begin
              Formulary.from_rack(rack).keg_only?
            rescue FormulaUnavailableError, TapFormulaAmbiguityError, TapFormulaWithOldnameAmbiguityError
              false
            end
          else
            true
          end
        end.map(&:basename)

        return if unlinked.empty?
        inject_file_list unlinked, <<-EOS.undent
        You have unlinked kegs in your Cellar
        Leaving kegs unlinked can lead to build-trouble and cause brews that depend on
        those kegs to fail to run properly once built. Run `brew link` on these:
        EOS
      end

      def check_xcode_license_approved
        # If the user installs Xcode-only, they have to approve the
        # license or no "xc*" tool will work.
        if `/usr/bin/xcrun clang 2>&1` =~ /license/ && !$?.success? then <<-EOS.undent
          You have not agreed to the Xcode license.
          Builds will fail! Agree to the license by opening Xcode.app or running:
              sudo xcodebuild -license
          EOS
        end
      end

      def check_for_latest_xquartz
        return unless MacOS::XQuartz.version
        return if MacOS::XQuartz.provided_by_apple?

        installed_version = Version.new(MacOS::XQuartz.version)
        latest_version    = Version.new(MacOS::XQuartz.latest_version)

        return if installed_version >= latest_version

        <<-EOS.undent
          Your XQuartz (#{installed_version}) is outdated
          Please install XQuartz #{latest_version}:
            https://xquartz.macosforge.org
        EOS
      end

      def check_for_old_env_vars
        if ENV["HOMEBREW_KEEP_INFO"]
          <<-EOS.undent
          `HOMEBREW_KEEP_INFO` is no longer used
          info files are no longer deleted by default; you may
          remove this environment variable.
          EOS
        end
      end

      def check_for_pth_support
        homebrew_site_packages = Language::Python.homebrew_site_packages
        return unless homebrew_site_packages.directory?
        return if Language::Python.reads_brewed_pth_files?("python") != false
        return unless Language::Python.in_sys_path?("python", homebrew_site_packages)
        user_site_packages = Language::Python.user_site_packages "python"
        <<-EOS.undent
          Your default Python does not recognize the Homebrew site-packages
          directory as a special site-packages directory, which means that .pth
          files will not be followed. This means you will not be able to import
          some modules after installing them with Homebrew, like wxpython. To fix
          this for the current user, you can run:

            mkdir -p #{user_site_packages}
            echo 'import site; site.addsitedir("#{homebrew_site_packages}")' >> #{user_site_packages}/homebrew.pth
        EOS
      end

      def check_for_external_cmd_name_conflict
        cmds = paths.flat_map { |p| Dir["#{p}/brew-*"] }.uniq
        cmds = cmds.select { |cmd| File.file?(cmd) && File.executable?(cmd) }
        cmd_map = {}
        cmds.each do |cmd|
          cmd_name = File.basename(cmd, ".rb")
          cmd_map[cmd_name] ||= []
          cmd_map[cmd_name] << cmd
        end
        cmd_map.reject! { |_cmd_name, cmd_paths| cmd_paths.size == 1 }
        return if cmd_map.empty?
        s = "You have external commands with conflicting names.\n"
        cmd_map.each do |cmd_name, cmd_paths|
          s += inject_file_list cmd_paths, <<-EOS.undent

            Found command `#{cmd_name}` in following places:
          EOS
        end
        s
      end

      def all
        methods.map(&:to_s).grep(/^check_/)
      end
    end # end class Checks
  end
end