[rubygems/rubygems] Backport binstub race condition fix to Bundler

https://github.com/rubygems/rubygems/commit/b07e46820d

lib/bundler/rubygems_ext.rb

@@ -30,6 +30,27 @@ module Gem
     end
   end
 
+  # 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+"
+
+      File.open(path, flags) do |io|
+        begin
+          io.flock(File::LOCK_EX)
+        rescue Errno::ENOSYS, Errno::ENOTSUP
+        end
+        yield io
+      rescue Errno::ENOLCK # NFS
+        if Thread.main != Thread.current
+          raise
+        else
+          File.open(path, flags, &block)
+        end
+      end
+    end
+  end
+
   require "rubygems/specification"
 
   # Can be removed once RubyGems 3.5.15 support is dropped

lib/bundler/rubygems_gem_installer.rb

@@ -81,6 +81,26 @@ module Bundler
       end
     end
 
+    if Bundler.rubygems.provides?("< 3.5.15")
+      def generate_bin_script(filename, bindir)
+        bin_script_path = File.join bindir, formatted_program_filename(filename)
+
+        Gem.open_file_with_flock("#{bin_script_path}.lock") do
+          require "fileutils"
+          FileUtils.rm_f bin_script_path # prior install may have been --no-wrappers
+
+          File.open(bin_script_path, "wb", 0o755) do |file|
+            file.write app_script_text(filename)
+            file.chmod(options[:prog_mode] || 0o755)
+          end
+        end
+
+        verbose bin_script_path
+
+        generate_windows_script filename, bindir
+      end
+    end
+
     def build_extensions
       extension_cache_path = options[:bundler_extension_cache_path]
       extension_dir = spec.extension_dir