doctor: move code away from cmd/

Closes Homebrew/homebrew#47665.

Signed-off-by: Baptiste Fontaine <batifon@yahoo.fr>

4 files changed, 9 insertions, 1349 deletions

diff --git a/Library/Homebrew/cmd/doctor.rb b/Library/Homebrew/cmd/doctor.rb
index 142c7fe0e..fe230c8bc 100644
--- a/Library/Homebrew/cmd/doctor.rb
+++ b/Library/Homebrew/cmd/doctor.rb
@@ -1,1318 +1,15 @@
-require "cmd/missing"
-require "formula"
-require "keg"
-require "language/python"
-require "version"
-
-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 = %W[#{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
-
-  # Sorry for the lack of an indent here, the diff would have been unreadable.
-  # 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
-      "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
-      "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
-    if !ARGV.homebrew_developer? && OS::Mac.prerelease? then <<-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
-    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"
-
-    libs = Pathname.new("/usr/bin/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?
-
-    unless libs.include? "/usr/lib/libxcselect.dylib" then <<-EOS.undent
-    You have an outdated version of /usr/bin/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
-      The #{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
-    The /usr/local directory is not writable.
-    Even if this directory was writable when you installed Homebrew, other
-    software may change permissions on this directory. Some versions of the
-    "InstantOn" component of Airfoil or running Cocktail cleanup/optimizations
-    are known to do this.
-
-    You should probably change the ownership and permissions of /usr/local
-    back to your user account.
-      sudo chown -R $(whoami):admin /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($1) < Version.new("1.7.10")
-      git_upgrade_cmd = Formula["git"].any_version_installed? ? "upgrade" : "install"
-
-      <<-EOS.undent
-        An outdated version of Git was detected in your PATH.
-        Git 1.7.10 or newer is required to perform checkouts over HTTPS from GitHub.
-        Please upgrade: brew #{git_upgrade_cmd} git
-      EOS
-    end
-  end
-
-  def check_for_git
-    if Utils.git_available?
-      __check_git_version
-    else <<-EOS.undent
-    Git could not be found in your PATH.
-    Homebrew uses Git for several internal functions, and some formulae use Git
-    checkouts instead of stable tarballs. You may want to install Git:
-      brew install git
-    EOS
-    end
-  end
-
-  def check_git_newline_settings
-    return unless Utils.git_available?
-
-    autocrlf = `git config --get core.autocrlf`.chomp
-
-    if autocrlf == "true" then <<-EOS.undent
-    Suspicious Git newline settings found.
-
-    The detected Git newline settings will cause checkout problems:
-      core.autocrlf = #{autocrlf}
-
-    If you are not routinely dealing with Windows-based projects,
-    consider removing these by running:
-    `git config --global core.autocrlf input`
-    EOS
-    end
-  end
-
-  def check_git_origin
-    return if !Utils.git_available? || !(HOMEBREW_REPOSITORY/".git").exist?
-
-    origin = Homebrew.git_origin
-
-    if origin.nil? then <<-EOS.undent
-      Missing git origin remote.
-
-      Without a correctly configured origin, Homebrew won't update
-      properly. You can solve this by adding the Homebrew remote:
-        cd #{HOMEBREW_REPOSITORY}
-        git remote add origin https://github.com/Homebrew/homebrew.git
-      EOS
-    elsif origin !~ /(mxcl|Homebrew)\/homebrew(\.git)?$/ 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.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.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
-    gnubin = "#{Formulary.factory("coreutils").prefix}/libexec/gnubin"
-    if paths.include? gnubin then <<-EOS.undent
-      Putting non-prefixed coreutils in your path can cause gmp builds to fail.
-      EOS
-    end
-  end
-
-  def check_for_non_prefixed_findutils
-    default_names = Tab.for_name("findutils").with? "default-names"
-    if default_names then <<-EOS.undent
-      Putting non-prefixed findutils in your path can cause python builds to fail.
-      EOS
-    end
-  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 $HOME, which may cause Python
-    builds to fail. See:
-      https://bugs.python.org/issue6138
-      https://bugs.python.org/issue4655
-    EOS
-    end
-  end
-
-  def check_for_outdated_homebrew
-    return unless Utils.git_available?
-    HOMEBREW_REPOSITORY.cd do
-      if File.directory? ".git"
-        local = `git rev-parse -q --verify refs/remotes/origin/master`.chomp
-        remote = /^([a-f0-9]{40})/.match(`git ls-remote origin refs/heads/master 2>/dev/null`)
-        if remote.nil? || local == remote[0]
-          return
-        end
-      end
-
-      timestamp = if File.directory? ".git"
-        `git log -1 --format="%ct" HEAD`.to_i
-      else
-        HOMEBREW_LIBRARY.mtime.to_i
-      end
-
-      if Time.now.to_i - timestamp > 60 * 60 * 24 then <<-EOS.undent
-      Your Homebrew is outdated.
-      You haven't updated for at least 24 hours. This is a long time in brewland!
-      To update Homebrew, run `brew update`.
-      EOS
-      end
-    end
-  end
-
-  def check_for_unlinked_but_not_keg_only
-    unlinked = Formula.racks.reject do |rack|
-      if !(HOMEBREW_REPOSITORY/"Library/LinkedKegs"/rack.basename).directory?
-        begin
-          Formulary.from_rack(rack).keg_only?
-        rescue FormulaUnavailableError, TapFormulaAmbiguityError, TapFormulaWithOldnameAmbiguityError
-          false
-        end
-      else
-        true
-      end
-    end.map(&:basename)
-
-    return if unlinked.empty?
-    inject_file_list unlinked, <<-EOS.undent
-    You have unlinked kegs in your Cellar
-    Leaving kegs unlinked can lead to build-trouble and cause brews that depend on
-    those kegs to fail to run properly once built. Run `brew link` on these:
-    EOS
-  end
-
-  def check_xcode_license_approved
-    # If the user installs Xcode-only, they have to approve the
-    # license or no "xc*" tool will work.
-    if `/usr/bin/xcrun clang 2>&1` =~ /license/ && !$?.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
+require "diagnostic"
 
 module Homebrew
   def doctor
-    checks = Checks.new
+    checks = Diagnostic::Checks.new
 
     if ARGV.include? "--list-checks"
       puts checks.all.sort
       exit
     end
 
-    inject_dump_stats(checks) if ARGV.switch? "D"
+    checks.inject_dump_stats! if ARGV.switch? "D"
 
     if ARGV.named.empty?
       methods = checks.all.sort
@@ -1349,19 +46,4 @@ module Homebrew
 
     puts "Your system is ready to brew." unless Homebrew.failed?
   end
-
-  def inject_dump_stats(checks)
-    checks.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
 end
diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index dbd8f5c04..c2ef9a334 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -1,5 +1,5 @@
 require "blacklist"
-require "cmd/doctor"
+require "diagnostic"
 require "cmd/search"
 require "formula_installer"
 require "tap"
@@ -159,7 +159,7 @@ module Homebrew
   end
 
   def check_xcode
-    checks = Checks.new
+    checks = Diagnostic::Checks.new
     %w[
       check_for_unsupported_osx
       check_for_bad_install_name_tool
diff --git a/Library/Homebrew/cmd/missing.rb b/Library/Homebrew/cmd/missing.rb
index 6805548a8..3d70e5f35 100644
--- a/Library/Homebrew/cmd/missing.rb
+++ b/Library/Homebrew/cmd/missing.rb
@@ -1,30 +1,8 @@
 require "formula"
 require "tab"
+require "diagnostic"
 
 module Homebrew
-  def 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
-
   def missing
     return unless HOMEBREW_CELLAR.exist?
 
@@ -34,7 +12,7 @@ module Homebrew
       ARGV.resolved_formulae
     end
 
-    missing_deps(ff) do |name, missing|
+    Diagnostic.missing_deps(ff) do |name, missing|
       print "#{name}: " if ff.size > 1
       puts "#{missing * " "}"
     end
diff --git a/Library/Homebrew/cmd/update.rb b/Library/Homebrew/cmd/update.rb
index 9e2541434..436175b25 100644
--- a/Library/Homebrew/cmd/update.rb
+++ b/Library/Homebrew/cmd/update.rb
@@ -1,5 +1,5 @@
 require "cmd/tap"
-require "cmd/doctor"
+require "diagnostic"
 require "formula_versions"
 require "migrator"
 require "formulary"
@@ -15,7 +15,7 @@ module Homebrew
     end
 
     # check permissions
-    checks = Checks.new
+    checks = Diagnostic::Checks.new
     %w[
       check_access_usr_local
       check_access_homebrew_repository