From e4cc791f87700ea6d59d358e2f688fcc85c45676 Mon Sep 17 00:00:00 2001
From: nobu <nobu@b2dd03c8-39d4-4d8f-98ff-823fe69b080e>
Date: Tue, 30 May 2017 13:12:22 +0000
Subject: enum.c: check if reentered

* enum.c (cmpint_reenter_check): extract from nmin_cmp and
  nmin_block_cmp.

* enum.c (nmin_cmp): check if reentered before rb_cmpint.
  [Feature #13437]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@58971 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
---
 enum.c                 | 19 ++++++++++++-------
 test/ruby/test_enum.rb | 16 ++++++++++++++++
 2 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/enum.c b/enum.c
index 5c973e643d..362c706235 100644
--- a/enum.c
+++ b/enum.c
@@ -1263,16 +1263,24 @@ struct nmin_data {
   const char *method;
 };
 
+static VALUE
+cmpint_reenter_check(struct nmin_data *data, VALUE val)
+{
+    if (RBASIC(data->buf)->klass) {
+	rb_raise(rb_eRuntimeError, "%s reentered", data->method);
+    }
+    return val;
+}
+
 static int
 nmin_cmp(const void *ap, const void *bp, void *_data)
 {
     struct cmp_opt_data cmp_opt = { 0, 0 };
     struct nmin_data *data = (struct nmin_data *)_data;
     VALUE a = *(const VALUE *)ap, b = *(const VALUE *)bp;
-    if (RBASIC(data->buf)->klass) {
-	rb_raise(rb_eRuntimeError, "%s reentered", data->method);
-    }
+#define rb_cmpint(cmp, a, b) rb_cmpint(cmpint_reenter_check(data, (cmp)), a, b)
     return OPTIMIZED_CMP(a, b, cmp_opt);
+#undef rb_cmpint
 }
 
 static int
@@ -1281,13 +1289,10 @@ nmin_block_cmp(const void *ap, const void *bp, void *_data)
     struct nmin_data *data = (struct nmin_data *)_data;
     VALUE a = *(const VALUE *)ap, b = *(const VALUE *)bp;
     VALUE cmp = rb_yield_values(2, a, b);
-    if (RBASIC(data->buf)->klass) {
-	rb_raise(rb_eRuntimeError, "%s reentered", data->method);
-    }
+    cmpint_reenter_check(data, cmp);
     return rb_cmpint(cmp, a, b);
 }
 
-
 static void
 nmin_filter(struct nmin_data *data)
 {
diff --git a/test/ruby/test_enum.rb b/test/ruby/test_enum.rb
index 57616791bb..991bda9b3f 100644
--- a/test/ruby/test_enum.rb
+++ b/test/ruby/test_enum.rb
@@ -604,6 +604,22 @@ class TestEnumerable < Test::Unit::TestCase
       [o, o, o].sort_by {|x| x }
       c.call
     end
+
+    assert_raise_with_message(RuntimeError, /reentered/) do
+      i = 0
+      c = nil
+      o = Object.new
+      class << o; self; end.class_eval do
+        define_method(:<=>) do |x|
+          callcc {|c2| c ||= c2 }
+          i += 1
+          0
+        end
+      end
+      [o, o].min(1)
+      assert_operator(i, :<=, 5, "infinite loop")
+      c.call
+    end
   end
 
   def test_reverse_each
-- 
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