Spec 'Signal.trap ignores the signal when passed nil' OK for rx19:

  - extract Signal.trap from kernel/common/signal.rb to
    kernel/common/signal18.rb;
  - create a new file kernel/common/signal19.rb with new version for
    Signal.trap:
      - in case stattement, add a new +when nil+ statetement which
        set +prc+ to +nil+;
      - in +when "IGNORE", "SIG_IGN"+ statement, +prc+ is set to
        "IGNORE" string;
      - in Rubinius.watch_signal, replace +prc.nil?+ with
        +prc.nil? || prc == 'IGNORE'+;
      - return statements now return +nil+ when +old+ is false
        instead of "IGNORE";
  - modify kernel/common/load_order*.

kernel/common/load_order18.txt

@@ -99,6 +99,7 @@ random.rbc
 regexp.rbc
 regexp18.rbc
 signal.rbc
+signal18.rbc
 splitter.rbc
 splitter18.rbc
 sprinter.rbc

kernel/common/load_order19.txt

@@ -107,6 +107,7 @@ random19.rbc
 regexp.rbc
 regexp19.rbc
 signal.rbc
+signal19.rbc
 splitter.rbc
 splitter19.rbc
 sprinter.rbc

kernel/common/load_order20.txt

@@ -107,6 +107,7 @@ random19.rbc
 regexp.rbc
 regexp19.rbc
 signal.rbc
+signal19.rbc
 splitter.rbc
 splitter19.rbc
 sprinter.rbc

kernel/common/signal.rb

@@ -12,62 +12,6 @@ module Signal
   @threads = {}
   @handlers = {}
 
-  def self.trap(sig, prc=nil, &block)
-    sig = sig.to_s if sig.kind_of?(Symbol)
-
-    if sig.kind_of?(String)
-      osig = sig
-
-      if sig.prefix? "SIG"
-        sig = sig[3..-1]
-      end
-
-      unless number = Names[sig]
-        raise ArgumentError, "Unknown signal '#{osig}'"
-      end
-    else
-      number = sig.to_i
-    end
-
-    # If no command, use the block.
-    prc ||= block
-
-    case prc
-    when "DEFAULT", "SIG_DFL"
-      had_old = @handlers.key?(number)
-      old = @handlers.delete(number)
-
-      if number != Names["EXIT"]
-        Rubinius.watch_signal(-number, prc.nil?)
-      end
-
-      return "DEFAULT" unless had_old
-      return old ? old : "IGNORE"
-    when "IGNORE", "SIG_IGN", nil
-      prc = nil
-    when "EXIT"
-      prc = proc { exit }
-    when String
-      raise ArgumentError, "Unsupported command '#{prc}'"
-    else
-      unless prc.respond_to? :call
-        raise ArgumentError, "Handler must respond to #call (was #{prc.class})"
-      end
-    end
-
-    had_old = @handlers.key?(number)
-
-    old = @handlers[number]
-    @handlers[number] = prc
-
-    if number != Names["EXIT"]
-      Rubinius.watch_signal(number, prc.nil?)
-    end
-
-    return "DEFAULT" unless had_old
-    return old ? old : "IGNORE"
-  end
-
   def self.run_handler(sig)
     # Ignore nil handlers
     if handler = @handlers[sig]

kernel/common/signal18.rb

@@ -0,0 +1,61 @@
+# -*- encoding: us-ascii -*-
+
+module Signal
+
+  def self.trap(sig, prc=nil, &block)
+    sig = sig.to_s if sig.kind_of?(Symbol)
+
+    if sig.kind_of?(String)
+      osig = sig
+
+      if sig.prefix? "SIG"
+        sig = sig[3..-1]
+      end
+
+      unless number = Names[sig]
+        raise ArgumentError, "Unknown signal '#{osig}'"
+      end
+    else
+      number = sig.to_i
+    end
+
+    # If no command, use the block.
+    prc ||= block
+
+    case prc
+    when "DEFAULT", "SIG_DFL"
+      had_old = @handlers.key?(number)
+      old = @handlers.delete(number)
+
+      if number != Names["EXIT"]
+        Rubinius.watch_signal(-number, prc.nil?)
+      end
+
+      return "DEFAULT" unless had_old
+      return old ? old : "IGNORE"
+    when "IGNORE", "SIG_IGN", nil
+      prc = nil
+    when "EXIT"
+      prc = proc { exit }
+    when String
+      raise ArgumentError, "Unsupported command '#{prc}'"
+    else
+      unless prc.respond_to? :call
+        raise ArgumentError, "Handler must respond to #call (was #{prc.class})"
+      end
+    end
+
+    had_old = @handlers.key?(number)
+
+    old = @handlers[number]
+    @handlers[number] = prc
+
+    if number != Names["EXIT"]
+      Rubinius.watch_signal(number, prc.nil?)
+    end
+
+    return "DEFAULT" unless had_old
+    return old ? old : "IGNORE"
+  end
+
+end

kernel/common/signal19.rb

@@ -0,0 +1,63 @@
+# -*- encoding: us-ascii -*-
+
+module Signal
+
+  def self.trap(sig, prc=nil, &block)
+    sig = sig.to_s if sig.kind_of?(Symbol)
+
+    if sig.kind_of?(String)
+      osig = sig
+
+      if sig.prefix? "SIG"
+        sig = sig[3..-1]
+      end
+
+      unless number = Names[sig]
+        raise ArgumentError, "Unknown signal '#{osig}'"
+      end
+    else
+      number = sig.to_i
+    end
+
+    # If no command, use the block.
+    prc ||= block
+
+    case prc
+    when "DEFAULT", "SIG_DFL"
+      had_old = @handlers.key?(number)
+      old = @handlers.delete(number)
+
+      if number != Names["EXIT"]
+        Rubinius.watch_signal(-number, prc.nil?)
+      end
+
+      return "DEFAULT" unless had_old
+      return old ? old : nil
+    when "IGNORE", "SIG_IGN"
+      prc = "IGNORE"
+    when nil
+      prc = nil
+    when "EXIT"
+      prc = proc { exit }
+    when String
+      raise ArgumentError, "Unsupported command '#{prc}'"
+    else
+      unless prc.respond_to? :call
+        raise ArgumentError, "Handler must respond to #call (was #{prc.class})"
+      end
+    end
+
+    had_old = @handlers.key?(number)
+
+    old = @handlers[number]
+    @handlers[number] = prc
+
+    if number != Names["EXIT"]
+      Rubinius.watch_signal(number, prc.nil? || prc == 'IGNORE')
+    end
+
+    return "DEFAULT" unless had_old
+    return old ? old : nil
+  end
+
+end