Merge pull request #3174 from sjackman/popen-options

popen: Do not suppress stderr when HOMEBREW_STDERR

Library/Homebrew/extend/os/mac/development_tools.rb

@@ -9,7 +9,7 @@ class DevelopmentTools
         @locate[key] = if (located_tool = original_locate(tool))
           located_tool
         elsif MacOS.version > :tiger
-          path = Utils.popen_read("/usr/bin/xcrun", "-no-cache", "-find", tool).chomp
+          path = Utils.popen_read("/usr/bin/xcrun", "-no-cache", "-find", tool, err: :close).chomp
           Pathname.new(path) if File.executable?(path)
         end
       end

Library/Homebrew/system_config.rb

@@ -134,7 +134,7 @@ class SystemConfig
       # java_home doesn't exist on all macOSs; it might be missing on older versions.
       return "N/A" unless File.executable? "/usr/libexec/java_home"
 
-      java_xml = Utils.popen_read("/usr/libexec/java_home", "--xml", "--failfast")
+      java_xml = Utils.popen_read("/usr/libexec/java_home", "--xml", "--failfast", err: :close)
       return "N/A" unless $CHILD_STATUS.success?
       javas = []
       REXML::XPath.each(REXML::Document.new(java_xml), "//key[text()='JVMVersion']/following-sibling::string") do |item|

Library/Homebrew/utils/popen.rb

@@ -1,20 +1,20 @@
 module Utils
-  def self.popen_read(*args, &block)
-    popen(args, "rb", &block)
+  def self.popen_read(*args, **options, &block)
+    popen(args, "rb", options, &block)
   end
 
-  def self.popen_write(*args, &block)
-    popen(args, "wb", &block)
+  def self.popen_write(*args, **options, &block)
+    popen(args, "wb", options, &block)
   end
 
-  def self.popen(args, mode)
+  def self.popen(args, mode, options = {})
     IO.popen("-", mode) do |pipe|
       if pipe
         return pipe.read unless block_given?
         yield pipe
       else
-        $stderr.reopen("/dev/null", "w")
-        exec(*args)
+        options[:err] ||= :close unless ENV["HOMEBREW_STDERR"]
+        exec(*args, options)
       end
     end
   end