* array.c (rb_ary_sum): Don't yield same element twice.

Found by nagachika.



git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54609 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Sat Apr 16 01:16:02 2016  Tanaka Akira  <akr@fsij.org>
+
+	* array.c (rb_ary_sum): Don't yield same element twice.
+	  Found by nagachika.
+
 Sat Apr 16 01:03:32 2016  Tanaka Akira  <akr@fsij.org>
 
 	* array.c (rb_ary_sum): Fix SEGV by [1/2r, 1].sum.

array.c

@@ -5736,12 +5736,14 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary)
 
         f = NUM2DBL(v);
         c = 0.0;
+        goto has_float_value;
         for (; i < RARRAY_LEN(ary); i++) {
             double x, y, t;
             e = RARRAY_AREF(ary, i);
             if (block_given)
                 e = rb_yield(e);
             if (RB_FLOAT_TYPE_P(e))
+              has_float_value:
                 x = RFLOAT_VALUE(e);
             else if (FIXNUM_P(e))
                 x = FIX2LONG(e);
@@ -5763,10 +5765,12 @@ rb_ary_sum(int argc, VALUE *argv, VALUE ary)
         v = DBL2NUM(f);
     }
 
+    goto has_some_value;
     for (; i < RARRAY_LEN(ary); i++) {
         e = RARRAY_AREF(ary, i);
         if (block_given)
             e = rb_yield(e);
+      has_some_value:
         v = rb_funcall(v, idPLUS, 1, e);
     }
     return v;

test/ruby/test_array.rb

@@ -1,6 +1,7 @@
 # coding: US-ASCII
 # frozen_string_literal: false
 require 'test/unit'
+require "delegate"
 require "rbconfig/sizeof"
 
 class TestArray < Test::Unit::TestCase
@@ -2769,6 +2770,12 @@ class TestArray < Test::Unit::TestCase
     assert_int_equal(13, [1, 2].sum(10))
     assert_int_equal(16, [1, 2].sum(10) {|v| v * 2 })
 
+    yielded = []
+    three = SimpleDelegator.new(3)
+    ary = [1, 2.0, three]
+    assert_float_equal(12.0, ary.sum {|x| yielded << x; x * 2 })
+    assert_equal(ary, yielded)
+
     assert_raise(TypeError) { [Object.new].sum }
 
     large_number = 100000000