io.c: not shorten buffer unless succeeded

* io.c (io_setstrbuf, io_read): should not shorten the given buffer until
  read succeeds.  [ruby-core:55951] [Bug #8625]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46360 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 4 insertions, 4 deletions

diff --git a/io.c b/io.c
index 6926316569..653034dd58 100644
--- a/io.c
+++ b/io.c
@@ -2372,9 +2372,6 @@ io_setstrbuf(VALUE *str, long len)
 	long clen = RSTRING_LEN(s);
 	if (clen >= len) {
 	    rb_str_modify(s);
-	    if (clen != len) {
-		rb_str_set_len(s, len);
-	    }
 	    return;
 	}
 	len -= clen;
@@ -2902,7 +2899,10 @@ io_read(int argc, VALUE *argv, VALUE io)
 
     GetOpenFile(io, fptr);
     rb_io_check_byte_readable(fptr);
-    if (len == 0) return str;
+    if (len == 0) {
+	io_set_read_length(str, 0);
+	return str;
+    }
 
     READ_CHECK(fptr);
 #if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)