[ruby/irb] Enable to reassign a new block with "measure" command

https://github.com/ruby/irb/commit/b444573aa2

lib/irb/init.rb

@@ -157,6 +157,14 @@ module IRB # :nodoc:
       added = [:CUSTOM, IRB.conf[:MEASURE_PROC][:CUSTOM], arg]
     elsif block_given?
       added = [:BLOCK, block, arg]
+      found = IRB.conf[:MEASURE_CALLBACKS].find{ |m| m[0] == added[0] && m[2] == added[2] }
+      if found
+        found[1] = block
+        return added
+      else
+        IRB.conf[:MEASURE_CALLBACKS] << added
+        return added
+      end
     else
       added = [:TIME, IRB.conf[:MEASURE_PROC][:TIME], arg]
     end

test/irb/test_cmd.rb

@@ -294,6 +294,13 @@ module TestIRB
         "measure { |context, code, line_no, &block|\n",
         "  result = block.()\n",
         "  puts 'aaa' if IRB.conf[:MEASURE]\n",
+        "  result\n",
+        "}\n",
+        "3\n",
+        "measure { |context, code, line_no, &block|\n",
+        "  result = block.()\n",
+        "  puts 'bbb' if IRB.conf[:MEASURE]\n",
+        "  result\n",
         "}\n",
         "3\n",
         "measure :off\n",
@@ -306,7 +313,7 @@ module TestIRB
         irb.eval_input
       end
       assert_empty err
-      assert_match(/\A=> 3\nBLOCK is added\.\n=> nil\naaa\n=> 3\n=> nil\n=> 3\n/, out)
+      assert_match(/\A=> 3\nBLOCK is added\.\n=> nil\naaa\n=> 3\nBLOCK is added.\naaa\n=> nil\nbbb\n=> 3\n=> nil\n=> 3\n/, out)
       assert_empty(c.class_variables)
     end