[rubygems/rubygems] Make sure implementations of Gem.open_file_with_flock match

https://github.com/rubygems/rubygems/commit/174a8e5284

lib/bundler/rubygems_ext.rb

@@ -33,20 +33,17 @@ module Gem
   # Can be removed once RubyGems 3.5.14 support is dropped
   unless Gem.respond_to?(:open_file_with_flock)
     def self.open_file_with_flock(path, &block)
-      flags = File.exist?(path) ? "r+" : "a+"
+      mode = IO::RDONLY | IO::APPEND | IO::CREAT | IO::BINARY
+      mode |= IO::SHARE_DELETE if IO.const_defined?(:SHARE_DELETE)
 
-      File.open(path, flags) do |io|
+      File.open(path, mode) do |io|
         begin
           io.flock(File::LOCK_EX)
         rescue Errno::ENOSYS, Errno::ENOTSUP
+        rescue Errno::ENOLCK # NFS
+          raise unless Thread.main == Thread.current
         end
         yield io
-      rescue Errno::ENOLCK # NFS
-        if Thread.main != Thread.current
-          raise
-        else
-          File.open(path, flags, &block)
-        end
       end
     end
   end

lib/rubygems.rb

@@ -794,15 +794,14 @@ An Array (#{env.inspect}) was passed in from #{caller[3]}
     File.open(path, flags, &block)
   end
 
-  mode = IO::RDONLY | IO::APPEND | IO::CREAT | IO::BINARY
-  mode |= IO::SHARE_DELETE if IO.const_defined?(:SHARE_DELETE)
-  MODE_TO_FLOCK = mode # :nodoc:
-
   ##
   # Open a file with given flags, and protect access with flock
 
   def self.open_file_with_flock(path, &block)
-    File.open(path, MODE_TO_FLOCK) do |io|
+    mode = IO::RDONLY | IO::APPEND | IO::CREAT | IO::BINARY
+    mode |= IO::SHARE_DELETE if IO.const_defined?(:SHARE_DELETE)
+
+    File.open(path, mode) do |io|
       begin
         io.flock(File::LOCK_EX)
       rescue Errno::ENOSYS, Errno::ENOTSUP