Fix sudo prompt.

Library/Homebrew/system_command.rb

@@ -158,7 +158,7 @@ class SystemCommand
     options = {
       # Create a new process group so that we can send `SIGINT` from
       # parent to child rather than the child receiving `SIGINT` directly.
-      pgroup: true,
+      pgroup: sudo? ? nil : true,
     }
     options[:chdir] = chdir if chdir
 
@@ -174,7 +174,7 @@ class SystemCommand
 
     @status = raw_wait_thr.value
   rescue Interrupt
-    Process.kill("INT", pid) if pid
+    Process.kill("INT", pid) if pid && !sudo?
     raise Interrupt
   rescue SystemCallError => e
     @status = $CHILD_STATUS

Library/Homebrew/test/system_command_spec.rb

@@ -55,7 +55,7 @@ describe SystemCommand do
             .to receive(:popen3)
             .with(
               an_instance_of(Hash), ["/usr/bin/sudo", "/usr/bin/sudo"], "-E", "--",
-              "/usr/bin/env", "A=1", "B=2", "C=3", "env", *env_args, pgroup: true
+              "/usr/bin/env", "A=1", "B=2", "C=3", "env", *env_args, pgroup: nil
             )
             .and_wrap_original do |original_popen3, *_, &block|
               original_popen3.call("true", &block)