Support Process.daemon

Author: shunichi

lib/debug/session.rb

@@ -2421,8 +2421,20 @@ def fork(&given_block)
       end
     end
 
-    private def __fork_setup_for_debugger
-      fork_mode = CONFIG[:fork_mode]
+    module DaemonInterceptor
+      def daemon
+        return super unless defined?(SESSION) && SESSION.active?
+
+        _, child_hook = __fork_setup_for_debugger(:child)
+
+        super.tap do
+          child_hook.call
+        end
+      end
+    end
+
+    private def __fork_setup_for_debugger fork_mode = nil
+      fork_mode ||= CONFIG[:fork_mode]
 
       if fork_mode == :both && CONFIG[:parent_on_fork]
         fork_mode = :parent
@@ -2487,6 +2499,7 @@ def trap sig, *command, &command_proc
     module ::Process
       class << self
         prepend ForkInterceptor
+        prepend DaemonInterceptor
       end
     end
 
@@ -2522,6 +2535,7 @@ class << self
     module ::Process
       class << self
         prepend ForkInterceptor
+        prepend DaemonInterceptor
       end
     end
   end

test/console/daemon_test.rb

@@ -0,0 +1,32 @@
+# frozen_string_literal: true
+
+require_relative '../support/console_test_case'
+
+module DEBUGGER__
+  class DaemonTest < ConsoleTestCase
+    def program
+      # Ignore SIGHUP since the test debuggee receives SIGHUP after Process.daemon.
+      # When manualy debugging a daemon, it doesn't receive SIGHUP.
+      # I don't know why.
+      <<~'RUBY'
+        1| trap(:HUP, 'IGNORE')
+        2| puts 'Daemon starting'
+        3| Process.daemon
+        4| puts 'Daemon started'
+      RUBY
+    end
+
+    def test_daemon
+      # The program can't be debugged locally since the parent process exits when Process.daemon is called.
+      debug_code program, remote: :remote_only do
+        type 'b 3'
+        type 'c'
+        assert_line_num 3
+        type 'b 4'
+        type 'c'
+        assert_line_num 4
+        type 'c'
+      end
+    end
+  end
+end

test/support/console_test_case.rb

@@ -91,10 +91,10 @@ def debug_code(program, remote: true, &test_steps)
           if remote && !NO_REMOTE && MULTITHREADED_TEST
             begin
               th = [
-                new_thread { debug_code_on_local },
+                (new_thread { debug_code_on_local } unless remote == :remote_only),
                 new_thread { debug_code_on_unix_domain_socket },
                 new_thread { debug_code_on_tcpip },
-              ]
+              ].compact
 
               th.each do |t|
                 if fail_msg = t.join.value
@@ -109,11 +109,11 @@ def debug_code(program, remote: true, &test_steps)
               th.each {|t| t.join}
             end
           elsif remote && !NO_REMOTE
-            debug_code_on_local
+            debug_code_on_local unless remote == :remote_only
             debug_code_on_unix_domain_socket
             debug_code_on_tcpip
           else
-            debug_code_on_local
+            debug_code_on_local unless remote == :remote_only
           end
         end
       end