merge revision(s) 52745: [Backport #11738]

	* io.c (argf_getpartial): should not resize str if the second
	  argument is not given.
	  [ruby-core:71668] [Bug #11738]


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_2@52788 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 3 insertions, 1 deletions

diff --git a/io.c b/io.c
index 542e909784..511ff2615a 100644
--- a/io.c
+++ b/io.c
@@ -11180,7 +11180,9 @@ argf_getpartial(int argc, VALUE *argv, VALUE argf, int nonblock)
     }
 
     if (!next_argv()) {
-        rb_str_resize(str, 0);
+	if (!NIL_P(str)) {
+	    rb_str_resize(str, 0);
+	}
         rb_eof_error();
     }
     if (ARGF_GENERIC_INPUT_P()) {