3 files changed, 15 insertions, 0 deletions
diff --git a/Library/Homebrew/cmd/doctor.rb b/Library/Homebrew/cmd/doctor.rb
index b66f3c878..a0bef5162 100644
--- a/Library/Homebrew/cmd/doctor.rb
+++ b/Library/Homebrew/cmd/doctor.rb
@@ -237,6 +237,15 @@ def check_for_broken_symlinks
   end
 end
 
+def check_for_unsupported_osx
+  if MacOS.version >= "10.11" 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 breakage.
+    EOS
+  end
+end
+
 if MacOS.version >= "10.9"
   def check_for_installed_developer_tools
     unless MacOS::Xcode.installed? || MacOS::CLT.installed? then <<-EOS.undent
diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index d37b10c91..7f685b706 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -112,6 +112,7 @@ module Homebrew
   def check_xcode
     checks = Checks.new
     %w[
+      check_for_unsupported_osx
       check_for_installed_developer_tools
       check_xcode_license_approved
       check_for_osx_gcc_installer
diff --git a/Library/Homebrew/exceptions.rb b/Library/Homebrew/exceptions.rb
index 7eb053a7c..bad8d2c2d 100644
--- a/Library/Homebrew/exceptions.rb
+++ b/Library/Homebrew/exceptions.rb
@@ -216,6 +216,11 @@ class BuildError < RuntimeError
       puts "These open issues may also help:"
       puts issues.map{ |i| "#{i['title']} (#{i['html_url']})" }.join("\n")
     end
+
+    if MacOS.version >= "10.11"
+      require "cmd/doctor"
+      opoo Checks.new.check_for_unsupported_osx
+    end
   end
 end