diagnostic: move some more macOS doctor checks.

Move some `brew doctor` checks that are pretty macOS specific so they
are only run on macOS.

1 files changed, 71 insertions, 0 deletions

diff --git a/Library/Homebrew/extend/os/mac/diagnostic.rb b/Library/Homebrew/extend/os/mac/diagnostic.rb
index ff936c75a..58d8c633d 100644
--- a/Library/Homebrew/extend/os/mac/diagnostic.rb
+++ b/Library/Homebrew/extend/os/mac/diagnostic.rb
@@ -307,6 +307,77 @@ module Homebrew
           We recommend only installing stable releases of XQuartz.
         EOS
       end
+
+      def check_filesystem_case_sensitive
+        dirs_to_check = [
+          HOMEBREW_PREFIX,
+          HOMEBREW_REPOSITORY,
+          HOMEBREW_CELLAR,
+          HOMEBREW_TEMP,
+        ]
+        case_sensitive_dirs = dirs_to_check.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 because: 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
+        return if case_sensitive_dirs.empty?
+
+        volumes = Volumes.new
+        case_sensitive_vols = case_sensitive_dirs.map do |case_sensitive_dir|
+          volumes.get_mounts(case_sensitive_dir)
+        end
+        case_sensitive_vols.uniq!
+
+        <<-EOS.undent
+          The filesystem on #{case_sensitive_vols.join(",")} appears to be case-sensitive.
+          The default macOS filesystem is case-insensitive. Please report any apparent problems.
+        EOS
+      end
+
+      def check_homebrew_prefix
+        return if HOMEBREW_PREFIX.to_s == "/usr/local"
+
+        <<-EOS.undent
+          Your Homebrew's prefix is not /usr/local.
+          You can install Homebrew anywhere you want but some bottles (binary packages)
+          can only be used with a /usr/local prefix and some formulae (packages)
+          may not build correctly with a non-/usr/local prefix.
+        EOS
+      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")
+          <<-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"
+          <<-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
     end
   end
 end